OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Power Torque surges

I have just stripped and reassembled a Power Torque engine. Now it runs but revs and then dies down , then revs hard again......
You can mow a lawn but I have to stop and wait for revs to build up.
Must be a carb problem, not enough fuel flow.......
Any ideas? thanks
speedy

Did you change the needle to a yellow one? if so find the shorter white needle...
This causes the bowl to have less fuel in it due to the length of the yellow needles..
this may cause your issue..

Could also b sucking air from a bad or misaligned Oring

give the jet good clean out , dont disturb the primer cap if you can help it or swap it with one you know ran well be sure to be sure the hole isnt blocked and the filter screen is tiketyboo . hold it too a light look through the filter screen and clean out the main jethole .

if O ring is leaking relpace it too but you should be able to tell . if it leaked air it will leak fuel too so ........ wont run well as you described

The jet never had that piece of gauze on it, so I put another one in and it runs well now. I also have a new front plate with the primer on it.

Thanks guys for your tips....
Now to get the hot water system going...........
speedy

A bloke brought one of these around for me to look at on Sat, doing this surging thing, I changed the needle, checked the jet,changed the carby cam,poppet in correct position, checked the exhaust port and muffler. It starts first pull and seemed to run fine when I test run it but he just rang and said it was up to its old tricks again. Only thing I can think of is fitting a different carby body to it and see what that does, unless somebody has another idea, I don't think it would be a coil failing

Hi Norm, try another jet, it could be partially blocked causing it to run lean and hunt. Sometimes a different diaphragm spring helps and an older style diaphragm(the greeny colored ones) also as they are stiffer and don't respond as quickly to the governor setup.

Thanks Bigted, I had thought about replacing the jet, about the only thing I could think of, I will get to the bottom of it. Another thing I think it might be is the pull start top might be loose, found a couple like that recently. Apparently it has been doing this for a long time and I'm having a bit of trouble convincing him that it is a good mower

Being a two cycle something else to think about is the crankshaft seals. When you put the engine back together did you pressure and vac test the crankcase?

This assumes that the 2 cycles over there operate the same as ours.

Being a two cycle something else to think about is the crankshaft seals. When you put the engine back together did you pressure and vac test the crankcase?

This assumes that the 2 cycles over there operate the same as ours.

Hmmm how did I do a double post? Sorry and if the forum moderator can delete one tnx.

AVB, these motors are probably the best ever designed small motor ever manufactured, pull the pull start off, 3 studs and sitting there looking at you is the conrod, most basic motor ever built and tough as old nails. Big "O" ring under the starter and that seals the crank up. Lower seal seems to give little problems and a lot of these motors I am playing with are up to 40 years old and unless they are rusted up or destroyed by incorrect fuel, they will run, even with virtually no compression.Plastic carby on them is a pain to get right, but once sorted these are the best small engine ever designed and built, by far. Just [Censored] emission laws have put a stop to them this year. Good run for an engine design, 1974- 2016

I agree the emissions laws are a pain to say the least. Half the carbs here are needing reworks to just get an engine to run right. Then there is all the China junk coming in too.

And I like older motors too as they are simply better built engines as they were design to last and not just make it through the warranty period. I seldom get to anything much over 20 yrs old but once a while I do see an engine from the '60s. I even worked on one chainsaw that was over 55 yrs old and it ran better most of the brand new stuff today.

I'm doing my best to salvage these mowers from going to the tip, it is a terrible waste of resources. I have put out feelers that I will take a hundred of them, not sure where I would put them, but I will tackle that issue if it arrives and that is not only finding a place to put them but discussions with SWAMBO as to where she could park her car

This motor is still doing it, I have changed the main jet, "O" ring on the starter, I will eventually beat this, it must be something wrong with the carby body.

norm please check ignition modgel is making good earth some time pop reviet come loose

Good call freebird, I'll have a look at that, running out of other ideas, he is going to drop it off in a couple of days because he is sick of it, from what I can work out it has been doing it for some years. When I fix it I will let you know

My latest problem with these troublesome plastic carbys is the needles being so light are sticking up in the seat and won't drop down.I have p-lenty of new needles and they all do it. Does anybody have a fix for this. Attaching a bit of lead to it is not an option

And freebird, just as a follow up, it doesn't have the ignition module, I think the problem was a sticking needle on that as well

NormK,

Have you replaced the primer cap? That could fix your issue.

Hi Bruce, yes I have tried several primer caps and several needles,new and old ones. The needles all shut off no problems but then hold up in the seat, tap the top of the cap and it will release