3.0 Mercruiser - Is My Starter Bad??

cheesytaters

Cadet
Joined
Jun 28, 2009
Messages
7
Alright, so I have a 1990 Thompson, with a 3.0 Mercruiser. Last week, I replaced the head gasket and manifold gasket, the engine started and I shut it off since then, can't seem to get it to crank...So here's what I know:

When I turn the key, I can hear the starter engage with a loud click, but it won't turn over.

I can turn the engine over by hand, it's not seized.

It's acting like the battery is dead, but the battery is fully charged.

I took the starter and battery to autozone, they told me both were fine. However, I'm not completely convinced the starter test was accurate.

So my question is, with the starter engaging, but not turning, is it possible that my starter is bad or could it be something else. Any ideas you have will be helpful and very much appreciated. I'm trying not to throw parts at this thing.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,470
Re: 3.0 Mercruiser - Is My Starter Bad??

Alright, so I have a 1990 Thompson, with a 3.0 Mercruiser. Last week, I replaced the head gasket and manifold gasket, the engine started and I shut it off since then, can't seem to get it to crank...So here's what I know:

When I turn the key, I can hear the starter engage with a loud click, but it won't turn over.

I can turn the engine over by hand, it's not seized.

It's acting like the battery is dead, but the battery is fully charged.

I took the starter and battery to autozone, they told me both were fine. However, I'm not completely convinced the starter test was accurate.

So my question is, with the starter engaging, but not turning, is it possible that my starter is bad or could it be something else. Any ideas you have will be helpful and very much appreciated. I'm trying not to throw parts at this thing.

Ayuh,... Corroded, or Bad wirin', 'n wirin' ends....

By-pass the battery's cables with a set of jumper cables, 'n Try it...
 

cheesytaters

Cadet
Joined
Jun 28, 2009
Messages
7
Re: 3.0 Mercruiser - Is My Starter Bad??

Thank you both for your response. I've been reading these forums for a while now, and appreciate all of the great feedback you have provided. Bond-o, I tried bypassing with jumper cables from the battery to the starter and I get the same loud click of the starter engaging, but it still won't turn the engine. For good measure, I tried to turn it by hand again and I still can.
 

pevaguy

Petty Officer 3rd Class
Joined
Nov 28, 2010
Messages
84
Re: 3.0 Mercruiser - Is My Starter Bad??

Are you hearing the solenoid on the starter clicking or the "relay" solenoid clicking? Using a 12 volt test light while some one turns the key, check for current coming out of the solenoid to the starter motor itself. If no current there check for current on the big post of the starter (should be hot all the time). Next you have two small post on the starter solenoid, one is a ground and the other should be hot when you try to crank it, if no current there, go to the "relay" solenoid (probably on the other side of the engine below the manifold), It will have 2 large post and 2 small posts. The small posts will be a ground and the other small post will be hot when starting. The large posts, one hot all the time, the other hot when cranking.
If you are getting current to the starter motor and nothing is happening, it is the starter bad.
 
Top