Low vacuum

[GPinMT]

Restored a Frazer B1 6 rototiller and it won't start. Fresh overhaul but no vacuum. Could new crank seals be in backwards?

 

[John B.]

The old Frazer rototillers were a 2 cycle, at least those that I have seen and by your question about the crankshaft seals makes me believe yours is a 2 cycle as well. Yes, if they're in backward it absolutely create a vacuum leak. Does the engine try to start if you squirt a little gas thru the carburetor?

 

[GPinMT]

Yes its a 2 stroke. Will pretty much fire only a few times. Blew in the air cleaner hose while attempting to start it. Got it to run at least a few revolutions. Haven't tried a compression test but seems good putting my finger over the spark plug hole.

 

[JOCCO]

I am no guru of them things (been around them some) but on the two cycle part. Chainsaw, snowmobile etc. look up a pressure test of the crankcase. There are several ways to do it and it will pinpoint any leaks.

 

[GPinMT]

Good idea I never thought of that. I will try it.

 

[J.Wondergem]

If the crank seals are backwards it'll suck air.

 

[GPinMT]

Spark plug in, carb wide open it pulls about 3 in vacuum measured with a vacuum gage in the lower crankcase plug. Hand over carb intake its about 4 in. Compression is 50 lbs pulling the starter. Pulling the starter the vacuum jumps erratically from 3 in vacuum to about 3 lbs pressure. Acting like a 2 stroke with broken reed valves!

 

[GPinMT]

Found the impulse for the magneto appears to be in the wrong clock position. The impulse arm stop was at 10:00 and appears it needs to be at 2:00 for consistent operation. Will find out tomorrow.

 

[GPinMT]

Well she's still a no go! Guess it will have to come apart. Bummer

 

[GPinMT]

Time to get a shopping list together for some new gaskets