4 HP won't start...............

[LOWRIDER60]

I just picked this up and can't get it to run ,its a 1992 ,4MSHQ 4HP 2 Stroke.I can get around 100 psi compression and it has spark but I can't get it to start or cough even with starting fluid.........I took the carb apart to see if there is any issues,and checked the reed valves also,but no problems noted.

[86whaler]

I'm not familiar with those, but what about timing?

[LOWRIDER60]

4 hp yamaha

I was thinking about that ,but figured it should still cough a little......Maybe not.I suppose I'll take off the recoil assembly and flywheel to see if I have a broken key.

[LOWRIDER60]

4 hp yamaha

Took off the flywheel and the key was intact........tested some of the electronics (coil,cdi,etc.) with multimeter (ohms) and am now even more confused as I was not getting the parameters listed for these parts......and I had spark.......I think I need a better troubleshooting book.

[LOWRIDER60]

4 hp

Took it all apart and replaced the rings/honed the cylinder. Replaced all the gaskets but the powerhead gasket set did not come with a HEAD gasket.....Does this engine use a head gasket? Tried to start it and I could only get it started if I put a drill and socket on the flywheel nut to get it turning over fast enough to start,but could not get it started with just the pull start.Checked compression and could only get 50 psi out of it with pullstart,but 100psi when I used the drill and even more if I squirted oil in the cylinder.Pulled it all back apart and checked the cylinder bore and came up with 49.59mm and stock it should be 50mm????

[LOWRIDER60]

4 hp yamaha

Tore it all back apart and checked the cylinder with calipers.....50mm and appeared to be uniform throughout.Reassembled the powerhead and tried to do a leak down test ,but could not keep the piston from moving off TDC when I put air to it............Got it all back together and oddly enough got it started with the pull starter!!!!!!!!!! It only wants to run with the choke almost all the way closed though?????? I'm think'in its getting too much fuel so I'll have to take the carb apart again to see if I can locate the problem..............