Slow Cranking on 1989 Force 85 HP

I have a 1989 Force 85 hp OB. I bought a new battery for it last week and it started and cranked fine. This week I tried to start it and it turns over really slow. I thought the battery took a deuce on me so I returned it only for it to do it all over again. When I jump the motor off of a car it turns fast and fires right up. But a battery wont turn it fast enough.

Any ideas?

Thanks a ton in advance.

Re: Slow Cranking on 1989 Force 85 HP

Forgot to specify. I jumped it on the battery terminals to start it. Worked fine then. Im lost

Re: Slow Cranking on 1989 Force 85 HP

have you checked the voltage while it is running, mine usally runs around 13.9 on a digital voltmeter, however i have found that when my battery is about 75 to 85 % on the charge meter it seems like my starter drags just a little, good luck

Re: Slow Cranking on 1989 Force 85 HP

Its a fully charged battery. I also forgot to mention the motor started and ran fine about 10 times in 2 seperate outings before the problems started too.

Re: Slow Cranking on 1989 Force 85 HP

Well, if you are jumping it at the battery terminals and it is cranking fast and starting, you have eliminated the starter, the cables, and the connections.

THUS: It MUST be the battery! It does not have the voltage potential to crank the starter.

See if it is being charged. Use a VOM and check the voltage rectifier OR with the engine running see if voltage to the battery is about 14. Less than 13 and you are not charging the battery. This could be a bad rectifier or a bad stator. A bad stator will have infinite resistance with the wires disconnected from the rectifier. Normal resistance is about 1/2 to 1 ohm.

With all wires disconnected a GOOD rectifier will show continuity between the A/C terminals in one direction AND continuity in one direction only on the plus and minus terminals and the A/C terminals. I forget the exact test sequence but it is in almost any manual.

If you are charging properly: Since both batteries were new, it is time to check for a current drain somewhere in the system--not only the engine, but the boat as well. Are the gauges wired incorrectly so that they stay on when the engine is not running? Automatic bilge pump constantly running? Radio left on? ETC.

Re: Slow Cranking on 1989 Force 85 HP

I went out again today and started tracing back everything I could find. I tried to jump it again with the car and this time it did not work. Still had the slow cranking. So then I tried the battery directly to the starter, nothing doing there either. So then I took the starter apart. 2 of the 4 brushes where completely gone. Think maybe this had something to do with it turning slow? Long story short I ordered a brush kit off of this site and it will be here Friday. About 95% sure that is the problem.

Re: Slow Cranking on 1989 Force 85 HP

Ah! Yeah! Now you say it no longer turned quickly with the jump start. With two brushes missing, IF they were the brushes 180 degrees apart, then only about 1/2 of the windings are getting power, thus: slow cranking.

NOW: What about the brush springs? Were they still there and in good conition? Did they score the commutator? Do new springs come with the brush kit? What caused the two brushes to either break or wear prematurely?

These are questions you need to answer BEFORE you install new brushes, otherwise you may be wasting money and ruining a new set.

Re: Slow Cranking on 1989 Force 85 HP

Not sure why they wore early the entire thing was a mess. and only the 2 bruches that came off the post where gone. The new kit comes with springs