1990 force 120 h.p. slow cranking

[cookieman69]

Hello, The only way I can get this motor to start is with 2 fully charged battery's and then if it dosen't start right up and I have to crank for awhile it loses cranking power fast. after it is warm it fires right up any thoughts Thanks Mike

 

[fpdiver]

Re: 1990 force 120 h.p. slow cranking

Had the same motor until last year. My guess is a weak starter. It is drawing too much power to do too little work. Measure the current your starter is taking in with a clamp-on ammeter. (then ask the marina if that is too much)

Hello, The only way I can get this motor to start is with 2 fully charged battery's and then if it dosen't start right up and I have to crank for awhile it loses cranking power fast. after it is warm it fires right up any thoughts Thanks Mike

 

[Frank Acampora]

Re: 1990 force 120 h.p. slow cranking

The starter is grounded through the mount on the block and the mounting bolts. Check the mount to be sure it is clean and there is adequate cintact between the motor top plate and the block.

However: the most likely cause would be either worn brushes OR brush springs that have overheated and are not keeping the brushes tight against the commutator. Also check for carbonizing of the commutator. If it is black and not shiney copper color, the brushes will not have full electrical conductivity.

 

[john from md]

Re: 1990 force 120 h.p. slow cranking

The starter has been on there for almost 20years. If the boat was used alot, chances are it is due replacement. You can check the ground and clean connections like Frank advised but for reliability, it is probably time to change it. You can get a new one from 14rebuilders on ebay. His price is about $85 or so and he had a good reputation for a qualtiy product.

John