Mercruiser 3.0

Drock1979

Seaman
Joined
Sep 12, 2023
Messages
51
Hey Folks,

Gotta love our boats lol

Ok so purchased this boat end of last season was out once before winterizing.

This season replaced Impeller, belts, exhaust flapper, amongst other stuff.

Today went to test Impeller operation before being stuck in the middle of the lake overheating.

Turn the key and click, click, click. Battery is good, tried boosting same, tried portable diesel booster pack same.... short the two posts same so assuming starter? Any suggestions? Oh BTW yes I can turn the crank with wrench by hand it's not seized.

Appreciate all help and or suggestions
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,540
You have bad connection somewhere. Clean all connections with 150 grit sandpaper until they are clean and shiny enough your mother in law would eat off them
 

Drock1979

Seaman
Joined
Sep 12, 2023
Messages
51
You have bad connection somewhere. Clean all connections with 150 grit sandpaper until they are clean and shiny enough your mother in law would eat off them
All connections.... ok so start at starter.... then to the master switch all connections and the battery connections... any I might be missing? Probably missing a few others.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,540
Start at battery and work your way to the starter and block
 

1960 Starflite

Petty Officer 1st Class
Joined
Jun 23, 2011
Messages
377
Being a 4 cylinder there should be room to get to starter lugs. To rule out starter, unhook both battery cables +. - Attached a good set of jumper cables neg to engine block positive to starter lug/bolt, attach pos jumper cable to pos battery post. Firmly touch neg jumper cable to neg battery post. Starter should spin.
 

Drock1979

Seaman
Joined
Sep 12, 2023
Messages
51
I tried shorting the two lungs on the starter solenoid... what about the relay??? Was I doing it wrong?
 

Drock1979

Seaman
Joined
Sep 12, 2023
Messages
51
Being a 4 cylinder there should be room to get to starter lugs. To rule out starter, unhook both battery cables +. - Attached a good set of jumper cables neg to engine block positive to starter lug/bolt, attach pos jumper cable to pos battery post. Firmly touch neg jumper cable to neg battery post. Starter should spin.
What lug is the positive? And the negative goes directly to the block?
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,428
What lug is the positive? And the negative goes directly to the block?
yes negative goes from neg battery post to flywheel cover on back of block .

It is equally important to check and clean negative cables as positive cables ...
 

Pmt133

Chief Petty Officer
Joined
Jan 6, 2022
Messages
572
The slave solenoid on my 3.0l used to drive me crazy and just click. They seemed to like to fail every few years. Double check that as well as all connections first.
 

Drock1979

Seaman
Joined
Sep 12, 2023
Messages
51
The slave solenoid on my 3.0l used to drive me crazy and just click. They seemed to like to fail every few years. Double check that as well as all connections first.
That's the one between the battery and starter? Has two larger lugs and to small lugs?
 

Pmt133

Chief Petty Officer
Joined
Jan 6, 2022
Messages
572
That's the one between the battery and starter? Has two larger lugs and to small lugs?
Yeah. The one on mine was mounted to the shift linkage bracket. 2 yellow wires and two red wires. 96158T is the PN I think. I had power up to the starter from the battery (always hot) and was losing it on the yellow. Simple check with the test light confirmed... Sounded damn near identical to the starter solenoid clatter with the dog house closed but I was always able to get it to go cycling the key a couple times. It didn't bother me that much so the first time I let it go a season or two.

I noticed you said you jumped out at the starter though. That should remove that salve from the equation.... I should read more carefully.
 
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