25 Merc spilt block gasket failure

TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

tomme boy

Well-known member
Joined
Apr 2, 2013
Messages
260
Reaction score
0
Location
52732
My 25 Merc has been starting to run really bad at idle. It is also blowing gas out of the side of the block. I was told that this is a common problem with the Merc split case design.

I am going to have to either repair this or get a new motor. Has anyone here done this and how was it? Dealer here want 5 hours min to fix it over winter. He says there is no gasket per say. but just a sealant.
 
Your dealer is correct in that there is no gasket. "Gel Seal" is used to seal the machined surfaces in place of a gasket.
Be prepared to pull the powerhead and remove the front half down to the crank. Flywheel and ignition will have to be removed as well.
 
5 hours sounds about right if a dealer's doing it. I remember doing a few of those Pieces of junk back in the day. Merc never admitted that there was a problem with them.
 
I stepped into the business in '92, and got out of Mercury in 1998 or 9. Don't know what years were affected. Mercosil was also a headache.
 

Latest posts

Top