OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Powertorque revs and cuts out after half a tank of fuel

Hi Guys,

Hope you're all doing well!

I was hoping for some guidance on how to troubleshoot this issue I'm having.

I've got a Victa Powertorque that I rebuilt approx. 1 year ago, full carb rebuild, new O-rings all round, new head gasket. The only things I didn't touch were piston, rings, and main bearing seal.

The mower starts first pull and runs fine for half a tank, then it starts to surge and rev before cutting out. I'm suspecting that once it reaches a certain temp, there is an air leak causing it to run a bit lean and hot.

I have set the poppet valve to the low rev setting, this doesn't help as the issue isn't immediate.

Also, I can start it again immediately without any issues.

I've put a new plug in, which looks fine after a tank of fuel, not fouled or burnt. See pictures for plug condition after 1 tank of fuel.

Any thoughts on where to start with this one?

Cheers,
GT

Problem will be the junk float needle you are using, get yourself one from the carbymaster, he has had real float needles made with a viton tip and they unlike the junk being flogged on ebay work as a float needle should

Thanks Norm,

That was the first thing I did a few weeks back...

Unfortunately it didn't help.

Hi greens_tuf,

Here are a couple of things to look for as I don't think that it would be a carburettor issue.

1. What is the ring gap when in the cylinder? If the gap is to large it will cause the issue that you are having.
2. Do you have any movement in the crankshaft if so replace the bearing as the seal could be damaged.

Hi greens_tuf, after it cuts out, it restarts immediately without fuss? Do you need to top up the fuel or on the same fuel that's in the tank? Do you open the fuel cap to check the fuel level and hence allow it to vent?
I'm thinking if you need to top up before it restarts the your fuel filter is partially blocked( assuming it has the white felt type filter).
The other problem which is probably more likely is the fuel cap is not venting properly and once you open it to check the fuel level it allows fuel to flow again and hence it runs for the remainder of the tank.

I totally agree with bigted to be the first thing that you should do before going internally.

Thanks Bigted, Bruce.

I am running the gold type fuel filter, and it is still new. I actually drained 1/2 tank of fuel using the fuel tap, so the fuel is flowing OK, however, I had the cap off while doing this.

I did remove the cap to check the level of fuel after it cut out as I suspected it was running low and splashing around as I moved the mower back and forth, so again, this may be why it starts up again with no issues.

So to summarise, I used half a tank, it started revving and then cut out. I opened the fuel cap to inspect fuel level, and then started it again, no issues, but it cut out a minute after.

I'll try your suggestions and let you know how I go.

Ok put the fuel cap back on and try draining the fuel again, but I doubt this will be the answer if you say it started revving and cut out after one minute. The fact it is revving up indicates the fuel is leaning out or not flowing

Another thing to try is to disconnect the fuel hose from the carby, blow in it and then turn the tap on and this will help clean the tap filter although I doubt this to be the problem because I think you said you changed the filter, but checking everything eliminates any potential problem

And there is another possible cause to this, if the OP only fitted the new brass needle to the old primer cap the viton tip may be sticking in the old seat and once the fuel in the tank reaches about half way the weight of the fuel in the tank is not enough to pop the needle from the seat. Just a thought and don't ask how I know this

Have you been running E10 petrol at all? That could be the problem if you have. The see through fuel cap prism on older Victa petrol caps melt right onto the tap filter, clogging it. I had to replace one because of that.

Thanks guys for your helpful comments.

Just to answer them:
1. Fuel filter is clean.
2. I am using the full carbymaster rebuild kit
3. I am running 95 RON

I filmed the engine running after I gave it a refresh last year - It would idle at 3 different speeds according to throttle position. Even though I know these carbs aren't really designed to do that, it was very responsive.

Now the revs don't drop when the throttle is mid way between run and choke, so I suspect there is something else going on... Overall I think it is over revving, running hot, then cutting out. I have different revs at the choke position and run position, but I suspect the speed it is running when in choke, is actually what it should be doing at full throttle.

I hate those damn cut of switch terminals - I am going to start by replacing it with a proper switch and plug the carb because the terminal was interfering with the throttle a bit. Although I don't think it's related, I'd like to do it anyway.

If you are interested, here are some videos for your viewing pleasure (and listening pleasure of course!)

I will not waste my time with the junk design kill switch, I used to persevere with them but they are just to dodgey to rely on, I fit a push button kill switch on the cowl. You could also read up on my LM carb modifications. I have done countless numbers of them now and they work faultlessly

It doesn't sound like it's revving too high in the second video. All mine make that note.
1st video, which is the choke position you refer to? The lower revs with the lever forward or when you pulled it backwards?
The lower revs as shown are certainly not the normal full throttle level. The higher revs sounds right for full throttle.

Just an update...

I think this is a fuel delivery issue as it got the revs to drop by manual pumping of the primer bulb.

I ran it over the weekend with a full tank, ran fine till it got to the point where the fuel is in line with the top of the fuel filter, then it leans out and stops. I removed the fuel cap and it still did the same thing.

I manually checked all lines, decompression valve, diaphragm, etc. All clear and working fine.

I'm thinking it's the fuel filter? I'll replace with a new "non eBay" unit and provide an update.

Any thoughts?

Or go back to my original thoughts on the float needle, I have found before that because these needles are so light and they can stick in the seat and with the reduced gravity of the fuel above the needle it just stays shut . Pushing the primer just lifts a bit more fuel up that is sitting in the bowl, my guess if you kept just pushing the bulb it would eventually stop because there was no fuel left in the bowl

Yes try another tank tap and filter assembly. The inside of the tap may be obstructed due to poor forming in the mould process.

Going back to my previous post regarding the height of the fuel, I test all my Victas with a fuel bottle hanging from the roof, this way I don't have to fit the fuel tank, fight with the pull start to get it through etc. In doing this I discovered that if the fuel was too low sometimes it would not drop the needle, but also if had the bottle too high the needle wouldn't shut off. The new brass needles don't give me this problem

Hi Everyone,

I had one of these today and I found two things, one the fuel needle was in backwards and two in a low fuel situation the filter on the fuel tap doesn�t allow enough fuel to flow to the carb. The fuel filter was the long spongy white one.

Fitted the needle the right way around and replaced the tap. Also filled the tank up and had no further issues.

On a side note I have found a few of the yellow fuel taps have not been allowing fuel to flow at a correct rate, a bad batch?