1989 3.0 l mercruiser alpha one w/ ddis-Will not turn over

[Thomasabbott91]

New battery, new cables, new starter solenoid, new starter motor. I have a bypass button hooked up, and it sluggishly turns about 45 degrees then stops. I can turn the belt over a little bit, and same thing happens.

The only time it turns over all the way is when the spark plugs are out. I understand maybe it's stuck in the compression stage, but wouldn't the starter take care of that? How do I troubleshoot/fix it?

 

[alldodge]

Sounds to me that the motor is rusted up. When was the last time the motor ran?

 

[Thomasabbott91]

3 years ago. I bought it a couple of monthes ago

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Pull the drive off, to be sure it ain't the problem,.....

The entire drive, except for the prop shaft, turns with the motor's crankshaft,....

 

[hemi rt]

If the engine is seized you take the plugs out and pour some diesel fuel into the cylinders, put the plugs back in loosely to prevent dirt from getting in, let it sit for a couple of days then try and rock the motor back and forth (by hand). If it moves then try and turn the engine over 2 times by hand, leave the plugs out, make sure you have oil in it and use the starter to spin it over. If it spins over put the plugs in and try and start it, listen for abnormal noises and if heard shut it off right away and then pull the engine for a rebuild.