Have an unusal problem that has just surfaced with my near new OS 52 4 Stroke.... Never had a problem priming it until recently it would not prime at all.
I have always primed by having the throttle wide open than placing my finger over the exhaust. Then I turn the prop through a couple of strokes and the fuel sucks up through the fuel line and into the carby. Works every time and starts first flip.
Now, it won't prime at all unless I flip the prop really fast over and over heaps of times even then it sometimes won't prime unless I use an electric starter...
I have tried swapping fuel tanks and fuel tubing to no avail. I have checked the carby for leaks and also the backplate. No leaks found. I have readjusted the valves and checked for leaks around the exhaust. No leaks found. The engine has plenty of compression but it just won't suck the fuel up. Even when I finally get it to start it idles fine but full throttle running is very wierd. It goes rich,lean,rich,lean, rich,lean every second or so. It definitely sounds like an air leak somewhere but its got me stumped where it could be???
Could a sticky or bent valve cause this problem?? There just doesnt seem to be enough exhaust pressure getting to the fuel tank and enough suction from the cylinder. Yet the compression feels fine.
Appreciate any help here guys.
Cheers,
Troy.