80 hp 4 cylinder mariner electrical problems

Masonmoore

Seaman Apprentice
Joined
Jul 30, 2015
Messages
37
I bought my boat as a project and have just recently made progress on the motor. I had a grounding issue with the starter solinoid but re-wired the solinoid and fixed the grounding problem. When i first fired the motor i noticed the motor would crank but would only turn the flywheel very slow. I also noticed when the flywheel turned it also turned the prop but i know for a fact that it was not in gear. Is this a electrical problem or could the starter motor be bad? And does the prop moving have anything to do with my problem?

Thanks, mason
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Well, it still sounds like you have electrical issues, since the starter turns very slowly. It should turn at least 300RPM. Make sure all battery cable and the starter ground cable (you do have one right?) are clean and good. On those old motors, the cables can go bad under normal looking insulation. Look for bulges in the cable.

If the prop spins freely in both directions, it is in neutral. A cranking motor can cause the prop to turn, but not with any force, if it is in neutral.
 

Masonmoore

Seaman Apprentice
Joined
Jul 30, 2015
Messages
37
Chris1956 yes the starter motor has a ground cable but it is a little worn out. And ill be sure to double check the cables for bulges. Thanks alot
 

Masonmoore

Seaman Apprentice
Joined
Jul 30, 2015
Messages
37
Update- i fired the motor with the plugs out and it spun good so the starter motor isnt bad. I also jumped it off straight from the battery and its still turning real slow.this is after checking the starter power wires and grounds. Im starting to think that my battery is bad after sitting for a while without use. Going to get it tested
 
Top