mercrusier 2.5 need help

weightset

Seaman Apprentice
Joined
Sep 12, 2012
Messages
33
so i just got my first boat and it has a gm 2.5l mercrusier 120hp well last night when trying everything out for the first time i realized that i had no spark and the motor was turning over very slowly with the plugs out what could be causing my issues The boat is a 1970 silverline comoro 16.5 ft. I found some engine cast id numbers which are 3937746 f269 gm con2 any help would be greatly appreciated
 

weightset

Seaman Apprentice
Joined
Sep 12, 2012
Messages
33
Re: mercrusier 2.5 need help

Also what are the two top buttons used for the bottom raises and lowers however top two do not do anything may be wiring problem
2012-09-09_16-57-18_965.jpg
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: mercrusier 2.5 need help

Push the top two buttons at the same time and see if the outdrive raises. The slow turning of the engine could be as simple as a weak battery or bad connections. Check both.
 

RogersJetboat454

Commander
Joined
Jul 9, 2010
Messages
2,964
Re: mercrusier 2.5 need help

Start with the basics...
How old is the battery? If it's new, make sure it has a full charge.
If it's old, has it gone dead in the past? If so, and especially if it was dead for a long period of time, chances are it's in rough shape. Would be worth bringing it to any number of parts houses that offer free battery testing to see if it's still usable or a core return. How do the battery cables and connections look (both at the battery and engine)? Regardless they should be taken apart, thoroughly cleaned, and inspected. Any signs of corrosion, or acid infiltration in the cables from the battery warrants a new cable.

Have you tried turning the engine over with a socket and ratchet on the crank bolt with the plugs out? It should turn fairly easily. If not, remove the outdrive and repeat. If it gets better with the drive off you may have issues in the drive. If it has no difference, you may have issues in the engine. If the engine turns over by hand easily with the drive installed, AND, you are certain that the battery and its cables are in good shape (this is after you check the battery and cables), your starter might need a rebuild.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
Re: mercrusier 2.5 need help

The 2 top buttons are for "trailer". It should override the trim limit switch and raise the drive.
 

weightset

Seaman Apprentice
Joined
Sep 12, 2012
Messages
33
Re: mercrusier 2.5 need help

thanks for the help on the buttons will try it later another question is when i go to start the engine i pull the pull/push button on the throttle lever will let me roll engine over however when i go to put in gear as im pushing throttle forward the button will kick out and kick it back into neutral what can i do about that for a temporary fix till i can get it figured out the right way( probably have to buy new throttle control)
 
Top