I figured this was a good of place as any to start a last ditch effort to salvage my Yanmar YSM 12. 1980. It ran great through late Feb 2012 but has not started since. I now rely on my 7.5 kicker motor which eats plenty more gas than the diesel. If you don't know, this engine is a single cylinder with decompression chamber lever, fuel injected and fires via compression (no glow plugs). The fuel is good, filters were changed in Jan, fuel system bled in Jan, batteries are fully charged, and power at the starter tests 12.7 V with multimeter. Starter was just rebuilt to include solenoid. When I hit the start button it spins slowly. With the compression closed it spins even slower. It seems it used to spin much faster when starting. The teeth on the flywheel are good and the bendix is engaging properly. I can hand crank it some, but not nearly fast enough to get it going. Today, I did notice a black wire (small 12 guage) to one of my batteries start smoking during the start. It looks like the previous owners have by-passed most of the original engine controls but it obviously ran great like this for many years. I can't find any information about slow spinning engines during start up other than electrical which maybe is the problem. I redid all the positive cables and the connections are looking good. I haven't worked with the grounding system as much but it does test 12.7 on the multimeter from the solenoid + to the - on the starter bolts. Is their a way I can bypass everything to see if the flywheel is perhaps hung up....causing resistance? Also, I don't have the $$$ right now to take it in so everythings pretty much on me. I'm in Pensacola, Florida and the diesel repair rate is $90hr. I am free to any advice. Also, while I am using the old motor it has now been two months since this one has ran. I have the water intake closed since it did not start in Feb but is their anything else I should do (thinking winterization) since it sounds like this motor may be sitting off for the next few months.