Hi Norm,
Yes there are a few ways to check for leaks without doing a Vac or pressure test and I'm sure you've done these tests below.
You get different results depending on how bad the seals are leaking ,sometimes I just put about 10 squirts of oil into the
spark plug hole then put the plug back in ,then turn the motor over a few times ,after you let the mower sit for
a couple days you can see oil running down the crankshaft.
If you know the carby is good but the motor is running too fast you know there has to be air leaking into the
motor also when a motor runs and you turn the fuel tap off and the motor revs up before cutting out.
Sliding a 1 to 2 thou feeler gauge between the crank and the seal will be a loose fit when the seals are worn and hardened from age.
You can start a 2 stroke then spray starter fluid at the seal and if the revs change the seal is leaking.
I've had a few 2 strokes that will only rev out if you almost completely crush the snorkel tube when running ,must
be giving the engine more fuel to compensate for the extra air leaking into the engine.
Automotive seals generally stay soft for about 10 years,so as we know the seals are fairly suspect on old mowers etc.
Cheers
max.
