OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa V50 125cc/160cc (unsure) Reving hard.

Hey guys, first time post. Looking to get a bit of help as I've just purchased a pristine (engine wise) little Victa 2 stroke (125cc/160cc, not sure which), only issue is it's maxing it's revs as soon as you turn it on.

I've tried to replace as much little odds and ends as possible, including head gasket (had to look in the cylinder head to see how it was all going) spark lead boot, spark plug, o-ring inside the carby mount.

I was told that the diaphram might be an issue and to blow/suck the hose on the arse end of the carby, it gives a little each way but there's no continuous air flow (good I think?). The carby itself sits loosely on the mount, but pressing it on with the engine running doesn't seem to change the behaviour.

Any common fixes you guys may know of are much appreciated. I don't mind tearing this down.

Note: I just purchased it off a bloke, and it ran fine when he turned it on to prove it worked, but after transporting it 5minutes down the road and leaving it over night, it's messed something up.

OK the first thing that would really help is to know exactly what it is.Is it possible to take a picture and upload it? If not does it have any marking stickers on it to help.From what you saying it obversely has a decompresser value on it so it must be at least from the 1970's onwards.Does it have a metal carby or a plastic one? Picture would be fantastic if that is possible.I'm sure that we can work it out.

Strange that it worked ok at first, did you pour your own fuel in once you got it home? If so maybe its a little lean. Other thing to check would be the diaphragm as that has caused similar symptoms on some Victa that i've woked with.

Thanks guys, bit dark now to get a photo, but i'll try get one tommorow.
Blumby; The markings say it's a "Victa V50". From what i understand it's a plastic carby that you mount at a 45degree angle then lock on by twisting it.

Tiger; i've checked the diaphram and it has a little give either way but does not allow continuous flow-through, which is good from what i've read.

Picture tommorow afternoon hopefully

Thanks for the replies so far!

I'm thinking I may have knocked something during transport? if that's at all possible.

Hi there PrincessJamJam, and welcome to the forum, by the sound of it you have a 160cc powertorque engine, but the following steps are also applicable to the earlier full crank engines. It would appear there is an air leak somewhere, hence it revving its head off from startup. You mentioned the carby is loose on the manifoldso i think that would be where we should start. There are 2 orings on the manifold, one between the carby and manifold and a smaller one between the manifold and the block. There should also be a wavy washer on the manifold that the carby pushes up against when it's locked in place; it's purpose is to apply some backward pressure on the carby to prevent it from loosening itself off. Check these orings are present and intact and the wavy washer is also there. Also ensure that the 2 small phillips head bolts that hold the manifold to the block are firm.
Next, make sure the hose that comes off the diaphragm housing is connected on the block end also.
(Applicable to powertorque engine only) There is also a large oring that sits under the starter housing, take the 3 bolts off and check that oring is not pinched, broken or missing. Reassemble the lot and pray for the best!
Let us know how you go and dont hesitate to ask any questions.

Thanks Bigted; uploading a few photos (hopefully).

In regards to the wavy washer, I've just bought a new one it doesn't apply any pressure to the carby once it's in place.

All 3 hoses coming off the plastic housing are plugged into the correct places.

Lastly, these phillips head screws. I'm not sure ive come accross them, is there anyway you can get me a photo? or even a link to one.

Edit: most odds and ends (wavywasher, orings etc.) have JUST been purchased from the mower shop near my work.

1st pic: Is this white circle what the o-ring goes over? or am i missing something?

2nd pic: The angle of the Carby(?) whilst I am pressing down on it.

3rd pic: The angle of the carby whilst I am not pressing on it.

4th pic: The "wavywasher", not connecting with the carby. Am i missing a spacer or?

Looks like you got yourself in a jam jam princess, the oring goes on the same bit of pipe that your wavey washer is on,then push your carby over the pipe and slide it on over the oring this should give it a: tighter fit so first the wavey washer then your oring then you carby and it looks like you got the angle of the carby right. The white thing is a poppet valve . The poppet valve needs to
Have O on it and I think you need to turn it so the O faces in the direction of which the fuel goes in . Someone will probably be able to explain the poppet valve a bit clearer . Hope this helps you.oh and id say it's a 160.cheers,and there is a groove for the oring to sit in .

Roebuck: the poppet valve has marking "A" "B" and "C", and a little notch that i'm guessing helps spin it.

I'm sorry I can't remember which letter but I'm pretty sure it's c .

On your poppet valve you will notice 3 letters, A, B and C. They are there to assist you in positioning the poppet valve the correct way.
I have been taught that for all power torque engines the poppet valve must be set to 'C' next to the spray hole. Only exception is the Vortex engine it must be set to 'A'. If you set it to any other position it can apparently cause richer mixtures, lower governed speed and other abnormal conditions.
It's a victa powertorque engine, which yes, is a 160cc half crank motor.

Sorry Roebuck, I was posting the same time as you. This is not the first time it's happened, lol.
Well I guess your picture verify's my post. And yes PrincessJamJam, I've always just used that notch sticking out to move the poppet valve to the correct position.

Thanks guys, I'll attempt to sort it all out tommorow after work as it's gotten too dark to see anything haha.

Will keep you updated!

Wow this post has taken off like a bushfire on a 45 degree day with a strong westerly wind behind it.Anyway PrincessJamJam I found these files for a G4 LM carby of which you have it might explain it a little better than what we can.It does sounds a little like it may not be together right.
See how you go.




I do have some more pages of this part of the manual if you need them.

Information overload id say,step by step I reckon.cheers blumby.

Sorry there I just giving you those diagrams so you could what is suppose to be in it and how it goes together.

That's all good, I just thought for a first timer it might be a bit dawnting but good lot of information all the same.

Well it looks a lot but you'd know yourself it's not that hard.Even more so it is good information for somebody starting at least they can see what's in them and how they go together.It's the best way to learn head first and make the mistakes we all learn from our mistakes not others.

I've gotta say, that knowing how it works makes everything simpler.
Have not had time to get onto the mower tonight, i had to help my parent out moving some stuff around.

Very much appreciated Blum, I'll have a read through all that as I'd really like to have a better understanding of how the carby functions!

Sure anytime I can help I will. Yes it good to know how it works and goes together. Gives one a better understanding in diagnosing and fixing. Glad I could help.

I've taken off the starter housing, as instructed by BigTed. WOW..... I never would have thought an O-Ring could stretch THAT much.... if I were to turn the housing upside down, the o-ring would simply fall off.

Hoping this is the culprit for the air leak. Will update tomorrow after I attempt to track down a ring from work/mower shop.

Ok, so make sure you replace the starter oring with a genuine one, we've all tried other ones , but they're either too big, or too small or too fat, or too skinny and just don't seem to work right bringing you back to square one quickly.
The loose carby on the manifold is a concern and suggest to me that the oring is either not there, or squashed and flat(and probably hard) and therefore not doing it's job, so the engine sucks air, runs lean and over revs. I've taken a pic of the manifold you have and it shows where the oring should sit. Once you replace it with a nice new soft fresh one the carby should sit tight and not turn upward like it is in your photo. This would also be a good opportunity to make sure that the 2 phillips screws that hold the manifold to the block are tight(one on top and one on bottom), but dont rush out to remove it and replace the small oring between the block and manifold as this rarely gets damaged unless it is disturbed.

If the carb still does not sit right after replacing the oring and wavy washer then we'll have to look at whether the 2 tangs on the manifold that hold the carb in place are intact or whether the carb itself is worn or damaged.

Awesome, I'll pick up the two o-rings tomorrow (unless the shop shuts 2 hours early again).

the manifold nodes were worn, so i purchased a new carby manifold and it now sits on there really well, new o-rings for both sides of the manifold and a new ring under the starter housing.

STILL getting over-rev issues

Going to try a trick i saw on this forum while searching around, two washers inside the carby to lessen the throttle.

Otherwise, i might introduce the old carby to a sledgehammer and order a new one ^_^

If all the seals are done, vacuum hoses connected and carby diaphragm in place and it's still overrevving then theres only one more thing it could be...... the bottom crank seal is shot. That would require removing the piston/conrod assembly and the crank and bearings. But before we go to that extreme there is a basic check you can do. Look at the underside of the mower around the crank and see if it's wet and oily, or just sweaty. Sweaty is ok, wet and oily is not a good sign. A photo for the rest of us is a good aide and removal of the blade disk will help coz being a utility it will be hard to see, otherwise try getting some light through the side chute.

ohh, yeah, try the washers first, if that fixes it then the crank seal should be ok.

Have you made sure the vacuum port at the engine end is free and clear?

Anyone know what size the washers are for the throttle fix?

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