Toro 38517 Snowthrower repair questions

[jwales]

Toro Model 38517; Serial 220004489, snowthrower. Son in law says it started this winter and ran for a minute or so and just continued to run faster. Then he shut it off and tried to restart a couple hours later with no luck. I looking into some basic stuff first; check spark, pull and clean carb, check compression, etc. I can find the ignition coil air gap and proper spark plug but I do not know what compression should be, new or with age. Does anyone know what the compression was for this? AND any idea what would be acceptable (or minimum) compression for the engine to run?

Thanks

[RoyM]

That is a 2 stroke, it needs 125 psi to run. Will it fire if you squirt gas, NOT STARTING FLUID, down the carb throat? Did you try a new plug?

[bgsengine]

Toro Model 38517; Serial 220004489, snowthrower. Son in law says it started this winter and ran for a minute or so and just continued to run faster

I'd be looking to see if carburetor mountings may have come loose, intake gasket leaking, fuel starvation (stiffened diaphragm, perhaps) Starts up and runs then revs up faster, on a 2-stroke, typically means it's leaning out - so too much air or not enough fuel (or both) - Other than that might check and see if it has a governor spring come loose on it (if it has one of those vane governors for fixed speed) but generally I would bet on a carburetion issue.

[KE4AVB]

Boy this one is an oldie according the serial number.

IPL say that blower has a Briggs 84232 engine. Go to the Briggs downloads and down the 14_276535 service manual.

From the SM on compression.

Crank the engine using the rewind starter. Continue
cranking until meter reading stabilizes. The meter
reading should be approximately 115 PSI. (7.9 bar). If
compression is below 80 PSI (5.5 bar), look for:
• Loose cylinder head bolts
• Blown head gasket
• Worn bore and/or rings
• Broken connecting rod

Of all the 2C engine I have worked on I only seen one that start below 100 psi.

Also this engine does not use a diaphragm type but a float type according to the IPLs.. Could still leaning due trash in the float bowl. Note this used use old cork float originally but have been upgraded to a plastic float. PN 801316.

[jwales]

Well it’s running just fine. My tester said compression was between 115 - 120 psi. Set the coil gap which was not to far off to begin with. Pulled carb it was pretty clean but put it in the USC anyway. Gasket between carb and manifold had a tear in it. Replaced it and after everything put back together it started on 3rd pull. Runs good. Wish I had snow to test!
Thanks for the information everyone.