Force 120 cranking issue

[bouch1]

I put new rings/pistons in a 93 force 120, it cranks fine with plugs out, with 1 or more plugs in it will only crank 1 compression stroke, moves freely when using a wrench on the flywheel with all plugs in so I’m guessing it’s electrical, my battery is about 3-4 years old and boat has been out of commission for almost 2 years while I got to it. Does a new battery seem like the best place to start. All worked fine before teardown. (Battery showed fully charged before starting).

 

[Jiggz]

Personally, I would start with the starter itself. In fact, to get the battery out of the way, get another spare battery and jumper it with in parallel with the existing battery, or use a battery charger with starting capability with it and if the same symptoms show up, then it is not the battery.

As for the starter, try cleaning the commutator and brushes (might even need to replace them brushes) and put it back together. If the same symptoms show up, then drop the lower unit and try again. if symptoms go away it means something is binding with the lower unit. Otherwise you might need a new starter. Before running and buying a new one you might want to see if you can borrow one and test again.

 

[jerryjerry05]

Load test the battery.
Load testers, I paid 25$ for mine.
Clean the starter?
Check the connections and the battery cables.

 

[bouch1]

Thanks guys, mostly what I was thinking, at the solinoid volts are same as battery, I will have to get someone to turn key while I check at starter first, then go from there to starter if all looks fine.

 

[Jiggz]

Since it has not ran in 2 years, you need to check the battery connections and most especially the negative engine block terminal. And I do not mean, visual check or "hand shake" checks. I mean disconnecting and wirebrushing both mating surfaces until it's shiny clean. And then re-tightened.

 

[mla2ofus]

Had a 90 HP Force that did that without a rebuild. Took starter apart and cleaned it, put some grease in the front and rear shaft bushings. Problem fixed and it was still cranking good when I sold it 6 yrs later.
Mike

 

[bouch1]

Ok guys, finally had the time to clean up all connections and trace to solenoid and starter, cheap enough so I replaced both and cranking great, now just need to get it started, might get on the water this year!!! Thanks for all the help.