Starting problems - Merc 90

CharlieZulu

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
122
Hi folks:

I wonder if someone can diagnose my problem..... I'm only getting about 8.5V on the cranking motor when I turn the engine over. Needless to say, with that low voltage, starting is a bit of a chore, but after quite a few grunts, she will actually fire up. still, it isn't right.

When I disconnect the cable from the cranking motor, I get the full battery voltage at the end of the cable, so the solenoid is closing --- but the cranking motor is dragging the voltage down 50%. The flywheel and cranking motor pinion turn freely.

Brand new battery.

Any clues? Cranking motor toast?

DSC03042.jpg
 

Firsttimer1

Cadet
Joined
Aug 20, 2011
Messages
6
Re: Starting problems - Merc 90

I would check for a bad battery ground or starter ground if they have one not to fimilar with that engine as to where the grounds are. If that checks out you probably have a starter that is drawing to many amps. you should be able to bring to a automotive parts store and they can test the cranking amps and see if it is in spec...
 

CharlieZulu

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
122
Re: Starting problems - Merc 90

Brand new battery.

Also, I re-did all major connections and shined them up. I didn't really find any that were corroded anyway.

Guess it's time to take the starter out.:mad:
 

CharlieZulu

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
122
Re: Starting problems - Merc 90

I noticed that the gear on my cranking motor is permanently engaged with the flywheel. Shouldn't this retract somehow when the ignition is off?? How is this supposed to work?

I think I may have been running around with the cranking motor turning all the time while the motor is running. I have to think this can't be normal.

Advice?
 

Sunfish12

Petty Officer 1st Class
Joined
Feb 6, 2011
Messages
260
Re: Starting problems - Merc 90

That isn't normal. Wd-40 the gear until it goes up and down with your hand with no resistance. It will drop down when cranking is stopped with the key. As far as having the starter spin the whole time it was running, it could have over heated it.
 

CharlieZulu

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
122
Re: Starting problems - Merc 90

Does it drop down with gravity, or is it pulled down by some other means?
 

Sunfish12

Petty Officer 1st Class
Joined
Feb 6, 2011
Messages
260
Re: Starting problems - Merc 90

There is a spring on top of the gear that helps it drop down.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,116
Re: Starting problems - Merc 90

Charlie, when the engine fires, it should kick out the starter gear. So turn the flywheel a bit, key off, and see if the starter disengages.
 
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