failed stator cause 78 140 johnson

[petersbc]

Wanted to close the loop on this. Received the rebuilt Stator and checked it's resistance. It's now in range from the spec in the clymer manual. Installed it and was still having no spark issues. The battery was low so cranking speed was not ideal but the stator was putting out 140 DBA. After playing around with it checking this and that with the charger on it I disconnected the rectifier and it started. I was not sure if it was the rectifier or the fact the battery charged enough to bring the cranking speed up.

Checking the rectifier though it is bad. It's open in one direction that should show continuity and it is shorted to ground on one lead (showing 0 ohms both ways when reversing the test leads). I also have one bad coil. This is all very disheartening as when I bought it the motor ran. It did not run great and I'm sure that coil was bad when I bought it but the rectifier and stator issue is new.

The rest of those parts are being installed tomorrow and hopefully I can complete the fine tuning.

 

[petersbc]

Started the motor and it was still not running well. It would idle ok but would falter and smoke when rev'd. Looking at the linkage to the timer base I found the timing was not advancing so I pulled it all apart and cleaned and greased everything. Yesterday I tried to start it again and it would not start. The couple of time it did try to fire it backfired out the exhaust. That was a surprise and told me the timing was way off.

Since I did not know and could not find which cylinder was #1, (its the top Starboard cylinder) I pulled the plugs and probed the piston with a screwdriver while rotating the engine by hand. None of the cylinders were at TDC when the timing marks were. So I pulled the flywheel and found the key had sheared. Not sure if I had failed to tighten the flywheel nut and it sheared on the first attempt to start it but I replaced it and the motor runs great. Base timing is dead on, it advances and retards smoothly, the motor revs well and runs clean at higher RPMs. Now I need to get it out on the water an check it under load. Only a couple of weeks away form the first trip of the season.