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Troubleshooting A Victa Lawn Mower

In this tutorial we describe some quick tips to determining what may be wrong with a Victa lawn mower that won’t start.

Tools/Parts:

    • Spare Fuel Line
    • Spark Plug Socket
    • Spark Plug


Step 1

The first thing to check is whether the lawn mower has a spark – click here if unsure how to do that. If there isn’t a spark, replace the spark plug and try starting the mower.

Step 2

If there is a spark but the mower won’t start place a small amount of petrol into the hole which the spark plug screws into – usually easiest to syphon petrol from the mower using a small tube. Then tighten the spark plug in place and attempt to start the mower. If the mower starts but doesn’t continue to run, then the problem is most likely the carburetor, as it is not allowing petrol to flow through it. If the mower starts and continues to run then the carburetor is fine.

Step 3

If you determined the problem to be the carburetor then open it up and give it a service – click here for assistance. Things to pay particular attention to in the carburetor are: green/off petrol, main jet being blocked, position of the float (whether the needle is too worn), and the diaphragm – these will all need a good clean.

Step 4

Another common problem to watch out for is the throttle cable not working properly, this may be a cause for the mower not starting, and can also cause it not to turn off – click here for assistance on this topic.

104 Responses to “Troubleshooting A Victa Lawn Mower”

  1. I have a victa tornado mower. Recently it will not rev at the operating speed required, but will work on a semi idle basis. It will it consistently run with it nearly dying if I don’t tamper with the accelerator.

    I replaced the plug, diagram, accelerator cable, and float and needle. I also put in a new air filter.

    So I’m thinking that the fuel and air is ok and when I test the plug it has spark but I can’t tell if it’s consistent enough.

    The only other thing that I can think of is a blocked exhaust. It seems to run better when cold and then farts around when operating temp is gained, and probably gets worse.

    It tried to rev but cannot get there without farting and nearly stalling before I muck around again with the accelerator.

    What do you think the problem is?

    • If the Carburetor is clean and you cannot find any air leaks in the Tubing or Oil Seals, the first thing i would look at would be the Decompressor and the Vacuum Point on the Block of the engine, if the Vacuum line on top of the carburetor is malfunctioning it can cause those symptoms.

      • Decomperssion on mine seems to be part of the auto prime fuel system mine wont run either looks like my stepsons fked with it do you know where i can find some blueprints or tips on troubleshooting this setup? Looks like theres some sort of swich on the muffler box between exaust outlet appears to do nothing whats this for?

        • lachlan Osmotherly November 30, 2015 at 1:15 pm Reply

          Hi

          we could provide some advice if you send some images through to “support@pushmowerrepair.com”

          Regards
          Lachlan

      • I followed the carb float checking as mine was hard to start and would not run properly,whilst in parts I noticed the compression valve sensor unit was filthy also that the hose was loose, I removed it and cleaned it in petrol blowing air through the line showed a serious leak I then cut the offending peice of tube off (about 1.5 cm ) and used some hot water to soften the tube before pushing it back on. Reassembly proved where the answer lay. MarkinNam

  2. Hi, unfortunately you missed a step, you talk about being a spark, what about when there is no spark even after you have purchased a new spark plug ?

  3. Hi,
    I replaced the spark plug and make sure there is spark ,did the step 2 by place small amount of petrel into the spark plug hole, but still can’t start the engine.

    Any suggestion?

    thanks

    • lachlan Osmotherly October 30, 2015 at 8:03 am Reply

      Hi

      if you cannot get it to start with some petrol placed in the spark plug hole the next step is to do a compression test to determine if the piston and rings need to be replaced

  4. Hi my mower starts but I can only get it to idle. It doesn’t seem to have any revs?

  5. Hi,

    This site is an excellent source of information. However, I cannot find any solution as to what steps can be taken when the throttle cable in the carby keeps detaching from the attachment on the carby itself … do I need to buy a new throttle body, or is there a simple fix with two rivets and some mild steel or aluminium?

    Thoughts and suggestions would be much appreciated.

    • lachlan Osmotherly January 15, 2016 at 6:44 am Reply

      Hi Justin

      We have not devised any makeshift solutions for this problem at the moment a small piece of metal and some rivets could possibly work otherwise the throttle body would need to be replaced

    • Hi Justin,

      Depending on how the carb is damaged, you may be able to repair using a couple of cable ties and something that moulds like rubber or a piece of rubber shielded cable/wire.

      My cable would lift out of the guide and away from the carb.

      Feed the throttle cable into the carb, and clip the metal stop into the guide on the end of the carb.

      Place the rubber on the outside of the carb where the throttle cable feeds in and clips into the carb.

      Using the cable ties, strap the rubber down so that it presses the throttle cable into the guide.

      I hope this makes sense, and helps you solve your problem.

  6. Hi Justin

    Last week I changed the blades and the spark plug on my Victa. When I fired it up, it started fine, but it wouldn’t turn off. I had to disconnect the cable from the spark plug to stop the engine. Any suggestions please?

  7. My. 4 stroke is leaking oil and lot of smoke when u start it

    • lachlan Osmotherly April 21, 2016 at 9:27 am Reply

      It sounds like your mower has some serious problems I will need much more detailed information if you want any troubleshooting advice.

  8. I have victa 2 stroke that I had going ,then hadn’t started it for some time resulting in not starting just rebuilt the carby has good spark have cleaned vacuum lines cleaned fuel tank,tap and fuel line fresh fuel do you fellas have any ideas

    • lachlan Osmotherly April 25, 2016 at 11:35 am Reply

      If you have good spark and fuel at the spark plug the first thing I would check would be the compression of the lawn mower this is the most common issue if fuel and spark are present and the mower will not start.

  9. Hi, I have just purchased a second-hand Victa 505 160cc self propelled mower, it works fine to begin but then when I stop, the fuel constantly pours out through the rubber primer button, Any ideas?

    • lachlan Osmotherly May 1, 2016 at 12:08 pm Reply

      Hi Ian

      That means that there is too much petrol getting into the carby, You will need to remove the primer cap and inspect the float and needle.

  10. I have a Victa Commando which recently started surging at top speed, revs would increase then decrease until it finally stalled. I replaced top and bottom seals and the seal on the carby spigot and overhauled the G4 carby and yet the problem still remains. Any clues on what this might be. Keep in mind that it runs on low speed with only light surging but will keep running and it gets worse as it warms up. Any help will be much appreciated. Thank you.

    • lachlan Osmotherly May 4, 2016 at 9:44 pm Reply

      Surging is more often caused by changes to the air fuel mix either by blockages in the carburettor or leaks in the intake, If both of those items seem in working order I would next look at the compression of the engine and the condition of the ignition system.

  11. I purchased one of your kits to rebuild the carby and have since got it to run. I can only get the mower to rev when I remove the breather line. Any thoughts?

    • lachlan Osmotherly June 6, 2016 at 2:37 am Reply

      Hi Ben

      The breather line controls the Rpm limit on these engines, The port of the engine block may be blocked completely causing the mower to not be able to rev as it should

  12. Thanks Lachlan, I can blow through the line into the block with little restriction. The revs increase when i throttle up, just not enough to cut the lawn.

    • lachlan Osmotherly June 7, 2016 at 4:11 am Reply

      Hi Ben

      It sounds like the mower is running a little rich, If you removed the breather hose and the revs increase. I would suggest checking the air filter and the intake hose for any restrictions.

  13. I have a two stroke exactly the same as in the tutorial and can’t start it. It has new fuel. I have put in a new spark plug. I have disassembled the Carb and all appeared good and throttle functions correctly. I can find no leaks etc. it has spark and runs for a few seconds when I add fuel to the cylinder. Fuel runs freely from the fuel hose with tank off when I turn tap on. What could my issue be?

    • lachlan Osmotherly June 12, 2016 at 11:55 pm Reply

      Hi Peter

      if it runs with fuel in the cylinder but does not continue to run the issue is most likely in the carburetor, There is a small passage behind the brass jet you can try clearing this out with a small needle or some wire. I would also check the float and needle to make sure they are not sticking, You can shine a light on the primer cap to see how much fuel is behind it, It should be between 1/3 & 1/2 full

  14. Hi,

    I got victa lawn mover and it stops frequently and the smoke also emits very often.It stops when you start the lawn moving and does not start at all.
    Any suggestions please .

    • lachlan Osmotherly July 9, 2016 at 5:49 am Reply

      Hi

      I would first check the ignition wires inside the carburetor to see if they are coming into contact with each other when they should not be this would cause the mower to frequently shut down, Next I would check the compression of the lawn mower.

  15. I have a 2 stroke Victa 550SP. Like the one in the vid I think. It was running well then got carb problems so I replaced the entire carb. Has new air filter and plug.
    It starts okay and runs. Problem is it over revs. I have tried changing the setting on the carb from C to A and no difference (although I am not sure what changing that setting actually does). Eventually it stops working unless I put it back to choke position.
    I think it may be the decompressor. Any ideas how to fix this over rev problem.

    • lachlan Osmotherly July 12, 2016 at 6:04 am Reply

      Hi Paul

      Overrevving is a common issue there is a few ways to address it the first is to check your carburetor & intake for air leaks, It is also worth checking both the top & bottom crank case seals as these can allow extra air inside the engine.

      Here is some videos about the carburetor: https://www.youtube.com/watch?v=adwfGHztENE

  16. Victa 80 160cc series run fine for 34 years until now…
    Mower starts and runs fine at mid throttle but will not rev and torque up enough to throw grass to the back of the catcher!
    New plug , airfilter and new fuel mix but the intake sound only growls louder with throttle on with no increase in revs!
    Secondly I can get it to slowly increase revs to full speed by pulling air hose off and then it runs fast. Cleaned carb and tank, blew out tubes.
    Have not checked vacuum area and muffler for bolckage as it does run fast with no filter attached. It’s not the filter as I have replaced it 3 times thinking it was it. How do you adjust fuel mix on the plastic carbs? Any suggestions apart from engine rebuild welcome.

    • lachlan Osmotherly August 28, 2016 at 1:52 pm Reply

      Hi

      There is two main causes for this issue, A rich fuel mix caused by too little air or too much fuel getting into the engine. The only way to troubleshoot this is to thoroughly clean and check the carburetor for worn parts, Or a lack of compression reducing the power of the engine and its ability to rev, Being 34 Years old it is quite possible that is the case.

  17. Hi I have a late 70s full crank victa that starts and runs fine but is horrendous to get going again I also started it and shut it straight off to see if it was an issue to do with a hot engine and found it was the same hot or cold could this be compression ? Also I was thinking about taking the self propelled axle off my 550 mulcher and fitting it to my 505 push catcher would it fit or are there small differences? And short of finding a set of so handles I’d have to try drilling the holes for the so lever and lover cable bracket tensioner . any help would be great

    • lachlan Osmotherly September 9, 2016 at 4:05 am Reply

      Hi Karl

      It is unlikely to be compression as that should get better after running the engine, I would try turning the fuel tap off when the mower is running and waiting for that to cause it to shut down, Then turn the fuel back on and try restarting. Sometimes Victa mowers flood when they are turned off and become hard to start, I have not seen it done but with the similarities between the two models I sure it would be possible, Although as you expect I’m sure holes will need to be drilled.

  18. Thanx Lachlan I will see if it starts after turning fuel off and on I’ve used it a few times after refurbishing the carby and performs fine so was surprised when it would not start we’ll I say would not it did eventually long time later I also found if I leave for 10 it will fire straight up always fuel and spark present tho a little weak so I checked the electronic ignition module and found it to be around 6.7 ohm which I thought is verry high swapped it for a smaller later type hoping it would cure it but no .only other thing about this early full crank 160 engine is parts unless I’m wrong are they hard to find like piston rings where would I find the part number for them I took a goes which was wrong and when they arrived they were every small lol we’ll after trying this next step compression test I think . and hopefully the alxe will fit on to the 505 just leaving the tricky job of drilling the 3 holes for the tensioner bracket and lever on the handles if I can’t source some so handles . tho at this point I’ve just refurbished another 550 mucher and thought I’d test it other day all OK tick over nice low with one brass washer on poppet valve throttles up fine tho thought at first revs were a little high but after about a second revs fall slightly so the governor pipe from flywheel vacume point to diagram must be working so all was fine until abit of throttling up and down later and now I seem to have the opposite of your engines Paul and Berty now it revs to a moderate 2000 and will not tick over engine shuts down as did think cable had popped out also checked diagram had not been sucked in from around the edge on car by sorry to waffle on lol

  19. Ok, 80 series full crank 160; pulled carby and cleaned it and get a good start and idle. But stull won’t rev up to grass cutting speed!
    I believe it’s a carbon blocked muffler… How do I pull the muffler off to clean it out???

    • On those older models the muffler is held on with some bolts that also hold the top cowling on, Once the cowling is removed there are two clips that secure the exhaust these can be pried of with a flat head screwdriver. Once these clips are remove the exhaust should be free.

  20. Managed to sort the half revving and non tick over problem was the outer sheif of the throttle cable coming away from the worn grips on carby so all is OK with that one apart from little bit of oil that collects on the bottom head bolt its had new gasket and have re torqued bolts after hot its no major problem just strange lol I have to laugh at the speed of these mowers

  21. Hi, my mower starts and then quickly stops. What do you think is the Problem ?

    • Hi Lawrence

      It is mostly likely to be a problem with the carburetor causing not enough fuel to flow one the most has started.

  22. I have a strange issue with my Victa (not sure what model, but it is an old green one with a G4 carby) that I can’t seem to find any info on – be interested if you have come across it. I had to service my carby because the primer bulb was leaky. I did that and since putting it all back together it starts perfect – and will run ok if the throttle is left in the one position. However if I try to increase the revs the mower will stall, but if I try to decrease the revs, the mower will actually increase revs.. ? Its almost doing the opposite of what the throttle cable should do. Would be very interested to hear if you have come across this before !

    • Hi Mike

      I have not come across that particular issue before it sounds quite unique. If you send me a picture via the contact page I may be able to narrow down your model for you. It could be that the mower is running a little bit lean meaning too much air or too little fuel is making it into the engine, this could cause the symptoms you describe, You can test this by clamping the intake hose while the mower is running to reduce airflow and then observing how the engine responds.

      • Good idea – will give that a go tonight and see what it does. I’ll take a picture and send it thru tonight/tomorrow as I will be interested to see what model it is.

        Most people tell me to give up on this mower but I reckon it cuts better than most mowers I’ve owned !

        Cheers !

  23. We’ll found out the so 550 pro mulcher axle is an inch shorter than the 505 catcher and the hole for the height adjustment bar link is in a diff place . but anyways cant go with the I dear of removing the gearbox and axles and fitting to the 505s as its to short n tbh was trying to work out how I release the drive shaft to wheel end gear…..so will have to abandon that and look for a 505 with so …also the full crank victa is still a non starter turned fuel tap off then tried to restart and no .. So I guess its not flooding so I’m all out of idears wen it dose this I take the plug out and is wet with fuel and there’s always a spark

    • too bad about the compatibility of parts between the 505 & 550, It seems to be a tricky problem with your full crank motor, I would try the following, Replace spark plug if its not already new. Remove decompressor and plug hole with old spark plug to rule out decompressor issues, And finally replace any orings that have not been replaced already.

  24. Thanks Lachlan,

    What should I do?

  25. Thanks Lachie

  26. Thanks lachlan have changed g4 for one I know is good problem stiil the same plugs new compression test returned 90 psi first time then second time 83 engine cold is this still within the parameters of acceptable for a working engine? so I can’t think of anything only thing that was odd wen I had it was the top crank seal was out of its recess tho am sure it was running like that I pressed it back in with intention of ordering new dose not make sens I thought bottom end needed to be sealed I’m thinking of getting another engine

    • Hi Karl

      Those compression readings are not high but most Victa engines will start and run with anything from about 70 PSI Up, Erratic running conditions tend to occur at such levels of compression, Above 85 Most Engines would run normally. Yes the bottom end does need to be sealed, Engines will often run with small leaks but will lack power and may change revs without throttle adjustment due to the air leaks.

  27. Thanx Lachlan we’ll I know when it is running it doesn’t miss a beat revs are constant at idle and wide throttle.. I’m not sure what else could be causing it not to start second time ‘feel I’ve covered everything …I’ve recently brought 2 more victas that I believe are the same engine but with the g3 carb a vc 160 and 160 auto drive. Thinking of referbishing one and maybe use the other for parts not sure at the moment obviously its probly abit silly replacing a 1977 engine with 73 oh wel and prob a shame to brake one up … The drive bar lever is missing off the auto drive and I think its near on impossible to source one of those .. Can anyone tel me if the operation for drive is the same? The spring loaded wheel that aplys pressure to the belt…. Me thinking I could replace handles for one with the standard self propelled black plastic lever to do the job of the missing drive bar.. Also do these engines have points ?

    • It does seem a very odd problem you have encountered as you have addresses all the possible causes that I am aware of. I am not sure about the auto drive setup as I have not taken one apart. I believe the early VC 160’s run points if so they are located underneath the flywheel.

  28. hey ah I have a self propelled victa 2 stroke 550 series side discharge mower! runs like a dream starts first go. idles like a purring kitten. I have found out that when it runs at high revs tho that it shakes and vibrates badly.. when running so much that without knowing it, it drops to the bottom height setting and cuts dough nuts in my lawn??? ugh..

    How can I fix this sudden problem.
    Jason
    Redcliffe QLD Australia

    • lachlan Osmotherly October 5, 2016 at 11:46 pm Reply

      Hi Jason

      Large vibrations are not a good sign, There is a few things it can be.

      1. The blades may have become unbalanced, To fix this new blades and a through clean of the blade carrier should work.
      2. The Engine is over revving and running faster then it should, This will be due to air leaks in the crankcase or intake
      3. The Engine bearings are worn out and in need of replacement.

      • Hello!

        Wow I didn’t expect a reply? Im guessing its number 3.. I put new blades on it regularly, its definitely not over revving, runs smooth and idles at low revs. just love this old type mower my dad had one when I was a kid, you cannot get side discharge mowers that are self propelled these days with out paying big dollars!!!! and its a trusty 2 stroke. cheap to run.

        engine Barings? hmm any idea what they might cost and are they available.

        Thankyou for your reply.
        Jason

        • lachlan Osmotherly October 19, 2016 at 11:11 pm Reply

          They are available, Cost will be around $30 plus shipping depending on which type of Victa Engine you have on the mower, The older type has more bearings then the more modern models.

  29. Dear Victa specialist.
    I have Victa 35 clasic for same years with no one problem.Last week I changed blades, but
    I make mistake because I turn the mower on side and now is making smoke and running
    inconsistent.
    Please give me advice on how to fix this problem.
    Many thanks.

    • lachlan Osmotherly October 8, 2016 at 1:05 pm Reply

      Hi

      You will need to make sure the carburetor is free of oil as when tipped it may have filled up, Your fuel tank could also have oil in it, If you clean the carburetor & fill with fresh fuel then leave the mower running for a few minutes the smoke should clear up

  30. Hi I’ve got a problem with a mower layup similar to the one in the video ato the top of the page – when I try to start it, you can only pull the cord a short distance before it becomes very hard to pull, and there is smoke coming from the motor where the fuel line does into the motor.
    Any suggestions?

    • lachlan Osmotherly October 16, 2016 at 1:03 pm Reply

      Hi Adam

      There is two things that usually cause this, The blade carrier being loose, Not mounted or incorrectly mounted. Or the decompressor having a fault. I would first check the blade carrier is mounted firmly you should not be able to rotate it at all without the engine also rotating, Be sure to test it with the spark plug lead removed for safety.

  31. No voltage coming from ignition to create a spark.tryed a tester held to lead that connects to spark plug but no reaction from tester

    • lachlan Osmotherly October 19, 2016 at 9:09 am Reply

      You will need to further troubleshoot the issue by removing and testing the coil for continuity with a multi-meter. Depending on the coil in your mower you will be looking for around 9 Kohms or 14 Kohms read from the spark plug lead to the inputs on the coil.

  32. Hi Lachlan ,can you tell me what the 2 wires to the carburettor do on a G4 ?

    • lachlan Osmotherly December 3, 2016 at 3:20 am Reply

      The wires are moved when the throttle cable moves in order to turn off the mower, when not it contact the mower can run, when the wires torch the ignition coil is shorted out and will not produce a spark.

  33. Victa 2-stroke, about 10 y.o.
    Left out overnight in the rain. Oops.
    Fuel tap was still on. Double oops.

    When I pull cord, I get a dead-stop blockage like there is water in the cylinder….

    But it isn’t. It’s fuel. When I release the tension I can back up the cord a bit and then it will go around, until the next block.

    The fuel pours out of the exhaust onto the blade disc, and then being thrown around by the disc as I try starting it.

  34. Further to the last. I removed the spark plug, and fuel gushes out through the spark plug hole as I crank it over.

    • Hi Mate

      This can happen sometimes when the fuel tap is left open as in your case, The only thing to do is remove the spark plug and pull the starter until the cylinder is mostly empty, Once empty you will probably need to leave the spark plug out and put the mower in the sun for a few hours to evaporate the remaining fuel. Once the cylinder is dry you should be able to start as usual.

  35. Hi Lachlan,

    Fantastic website. I serviced my Victa Mastercut 460 today. Everything is pretty good. Carby is clean, the mower starts pretty well. Air filter is clean.

    It runs well and doesn’t stall – but is moderately smokey (white smoke). There is no obvious signs of fuel/oil leaking out whilst running) I’m not sure what the next step is.

    Should I –

    1. Check the fuel/oil ratio mix and experiment.

    2. Check the decompressor ( I guess not, as it runs fine?)

    3. Check somewhere else for leaks (loose fittings/seals?)

    4. Run it for longer and let it warm up. Do you warm a mower up on low revs or higher revs?

    Thanks,

    • Hi Charles

      White smoke is generally caused by water, If it is cold or wet where the mower is stored water can accumulate in the exhaust from condensation, Warming up the mower should clear up the white smoke, If not you should empty the fuel tank and check the mix is correct,

  36. Hi. My husband has a victa 2014 550ex vcs469 18″mower. He has taken the blade plate off to scrape all build up of dirt off. Put plate back on. Put new blades on 19″ ca09470b blades, which were recommended to us at the hardware store. Now the mower doesnt cut the grass at all. Blades are correctly put. Help!

    • lachlan Osmotherly December 14, 2016 at 1:40 am Reply

      Hi Lucy

      That sounds like an unusual issue, It would be best if you contact us via email using the contact page, If you can provide some pictures of the mower and the blades install we will do what we can to help.

  37. Hi , my Victa mower mulcher 2 stroke stopped running . In the top of the plastic seems a hole has melted through and very hot air was blasting out of it . Sounds like there is no exhaust attached any clue as to what has happened ?

    • It sounds like there is a problem with your exhaust maybe a hole has formed due to rust and the hot air has melted through the plastic?

  38. My victa 2stroke won’t stop unless I turn fuel tap off
    Is it because of the two wires not touching. .?

  39. Hi, how are you? Now this is a bit of a strange one. I was half way through mowing my lawn ( the lawn was a little wet ) and the mower stopped dead. It did it once before in the past and I fix the problem, changed the spark plug. No prob. It’s a Victor 2 stroke Hurricane. I did the same. The old spark plug was little hard to get off, ( it took a little force ), but I got it off. I replaced it with exactly the same spark plug ,NGK BPMR4A. When I was tightening it up it got to the point when screwed in, a 1/4 turn more it would loosened again, it did it all the time. I tried to start the mower, when the plug was at its tightest, I got a bag and the spark plug blew out of it’s position. So it’s not tightening. I checked for fuel leaks, noticed when I turned the fuel on to start I saw a drop or 2 of petrol dropped out of cylinder. Not sure if is a leak or flooded. Not sure what’s happening. Thank you.

    • lachlan Osmotherly February 6, 2017 at 1:40 am Reply

      Hi Donny

      The problem is that you have over-tightened the spark plug and damaged the thread this means that it is no longer possible to properly install the spark plug without getting the thread repaired. In order to repair the thread you will either need to purchase a thread repair ki, Replace the whole cylinder head or take it to your local shop to have them repair the thread damage.

  40. Thanks for that, with the repairs and a service, roughly what would the costs be?

  41. victa 2 stroke motor 160cc it has a pully and belt connected to blades slasher
    the problem is it is not starting but when i transfer the motor to a push mower it does start ,,3 motors and all the same problem

    • lachlan Osmotherly March 10, 2017 at 5:35 am Reply

      Hi Dean

      The problem is most likely to be the tension of the belt being incorrect causing it to slip when the starter is pulled, The belt needs to turn the blades with no slippage otherwise the engines ignition timing is effected and it will not start.

  42. Have an 80 series motor,it has developed a problem where it only runs at top revs.Replaced carby and problem persists????

    • lachlan Osmotherly March 26, 2017 at 10:07 am Reply

      Hi Dave

      High rpms are most often due to air leaks, If you have replaced the O-rings in your carburetor then the most likely problem is worn out crankcase seals which are sucking extra air into the engine

  43. Have a victor mustang starts up ok but stops after a few minutes new spark plug, but keeps stopping

  44. Hi Lachie,

    I have had some problems with the last couple of needles I’ve bought. They are getting caught in the jet and therefore not releasing petrol. Are they a fraction wide or is there something else askew? I bought one of the needles from you.

    Regards,

    Tony

    • Push Mower Repair May 23, 2017 at 2:04 am Reply

      Hi Tony

      due to the nature of the plastic needles it is not an uncommon issue for them to get stuck as they have very little weight, In most cases a inspection for any rough spots and a light sand of the edges of the needle will solve the problem.

  45. Thanks, the old needles seem to be more reliable, ie ones from old mowers, is there any reason why the more recent ones are more problematic.

    • Push Mower Repair May 24, 2017 at 4:49 pm Reply

      Hi Tony

      There is no reason we are aware of for the newer needles to perform worse than the older ones

  46. Hi Admin,

    I have similar symptoms as Roger on the 15 May 2014. My 2 stroke mower recently wont rev at full throttle and its sits at semi rev range regardless of throttle adjustment. I did have an issue where at full throttle was making the motor choke up and splatter all over the place but i have corrected that .It starts perfectly and idles OK. I have watched your fantastic tutorial videos for troubleshooting and the few part series of the G4 carburetor over and over a few times just in case i have missed a step.
    To date, I have checked and changed the spark plug, check the decompressor – working OK, change the petrol tap, fuel line, changed the needle, primer cap seal and checked the float operation – working OK, disassembled the carburetor a few times and checked the diaphragm, lifter, both springs, throttle body movement in carburetor , vacuum port on flywheel to see if its blocked, checked both vacuum hoses from decompressor to back/rear of carburetor and checked the vacuum hose from vacuum port to the top of carburetor and all seemed OK not blocked or cracked in any shape or form. To your knowledge has this something to do with the carburetor? right?

    on another note, i have a friend who’s one of of his 2 stroke is over revving, what do you suspect the issue is with that one

    What do you think the issue is?

    • Push Mower Repair May 24, 2017 at 4:57 pm Reply

      Hi Vinnie

      There is a few things you can do to narrow down the problem, Does the mower blow alot of smoke? excess smoke and slower revs would suggest a rich fuel mix, You can test this by removing the air hosing that is connected to the carburetor and starting the mower, This should allow a significant amount of extra air into the carburetor and if this allows faster revs it would suggest your problem is too rich a mix, This can be caused by worn out parts or faulty brass jets.

      For Over revving the opposite is usually the case, You can test for a lean mix by removing the air filter then starting the mower, Once running use the handle of a screwdriver or similar sized object to block airflow into the intake pipe, The mower should either stop or slow down significantly, If this does not happen it means there is air leaks within the intake or crankcase causing a lean fuel mixture and fast rpm. Things to check to solve this are looking for cracks in the air intake hose, Checking the rubber boot & plug in the carburetor are properly installed, or if a on/off switch has been installed instead making sure to plug the whole up, Replacing carburetor manifold o-rings, checking both the top and bottom crankcase seals. Brass poppet valve spacers can also be installed to slow engine rpm as seen in this video: https://www.youtube.com/watch?v=adwfGHztENE&t=1s

  47. Hi again Lachie,

    I’ve noticed that my Powertorque won’t run when in Start position the way it used to. It will run fine though when I move the throttle control to the Run position. Does this suggest that there may be an air restriction?

    Regards,

    Tony

  48. I should have said in the previous post that it doesn’t start in the Start position but it starts in the Run position. It runs ok if I move into Start position it just won’t start from it.

    • Push Mower Repair May 28, 2017 at 5:24 am Reply

      It does suggest that when on the start position there is a change to the air/fuel mix it is difficult to determine the exact reason for the change in starting position It if works fine starting on run its probably best to leave it that way.

  49. Hi, I have a victa 35 classic that appears to run okay, but slows in rpm and stops after 20mins running. Starts and runs good again after a rest, and then shuts down again after a short time. I have changed the spark plug, but this made no difference. Many thanks for any advice. Cheer, Phil.

    • Push Mower Repair June 12, 2017 at 10:56 am Reply

      Hi Phil

      Its possible that it is the ignition coil they can fail when the mower warms up, Otherwise you can get Vapour lock in the fuel/air intake when it gets hot if the mower is clogged full of grass under the pull start housing

  50. I have a Victa 2 stroke and it runs extremely high and very noisy. I also think that it is using more fuel than it used to. Can you pleas advise what I should be looking into. Many thanks

    • Push Mower Repair July 26, 2017 at 3:38 am Reply

      Hi John

      Fast running is most often caused by air leaks in the carburetor, crankcase or intake. It is best to start with the intake and carburetor and check all the o-rings. It is also worth checking that the vacuum hoses are properly connected and that there is no cracks in the carburetor body.

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