Re: difficult to start
Start procedure.... Pump fuel bulb up hard, have engine in neutral, close choke, apply throttle, crank engine. It should start.
The throttle should be applied to a extent as far as it will go, or to an extent just so that it doesn't jam the manual starter.
Spark plugs should be Champion QL77JC4 plugs gapped at .040.
Check compression. Usually one can tell if that is okay on both cylinders simply by pulling the engine over BUT it's a good idea to purchase a compression tester to be positive the readings are okay and even.
Spark.... With the spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Does it?
If the above checks out okay, that leaves a fuel problem. Make sure that the choke butterfly is actually closing when you pull the choke lever out.
It's possible that the slow speed needle valve is misadjusted, and if so.....
(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)
Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.
When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
If all of the above is as it should be, and the problem still exists, that would indicate that the carburetor is fouled. Remove, clean, and rebuild it.
Note: Your 2nd post about the s/plugs.... That doesn't tell us exactly what plugs you're using or what gap you have them set at.
Let us know what you find.
