OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Popping when starting engine after rebuild

Hey Guys,

I can't seem to let this one go...

I changed the piston and rings over the weekend, the old piston was scored on the exhaust side. This didn't make a difference, I'm not surprised. I have essentially changed every o-ring, gasket, piston and rings, except for the lower crank case seal.

The fact that I can't get it to fire is leading me to think that it is an ignition issue, however, since I can see a spark when I test the plug I previously ruled this out.

So my question is, can the ignition modules be tested reliably using a multi-meter? and secondly has anyone ever experienced a case where the plug would fire under normal atmospheric pressure, but wouldn't fire under compression when in cylinder head?

I am going to try swapping the coil with one from a running motor to see if that makes a difference.

Thanks!

My money is still on the carby

I ruled that out by running my carby on a another mower and it idled perfectly. Also, I tried fuel in the spark plug hole without any success, so I'm leaning towards an ignition issue of some sort.

Another update, I replaced the coil with a working unit. Still no improvement, so I figured it must be compression.

I tested the compression and got a reading of 50psi, which seems low according to what I've been able to find online, however my running Mustang reads 60psi.

Thoughts anyone?

I will say it once again, compression is NOT the problem, vacuum maybe and you will not know that unless you have a vac gauge or you replace the bottom seal. If the seal is ok then it is the carby, and because it works on another motor is not proof it is ok, trust me I have been down that path.

Try the reverse then. Put a carby from a good mower onto it.

What about squirting some fuel in the spark plug hole? or some starter fluid? Wouldn't this point to carby issues if it does fire? Because this hasn't made a difference either.

But I will try a carb from another mower just to be sure.