2000 Mercury 25hp power head rebuild

fish4stripers · #1 August 16th, 2005, 11:50 AM

Hi Guys,

Nice site. Was selling my boat and got motor checked by Mercury shop. Says one cyl has 85 compression and the other is 125. So said I need powerhead rebuilt. He said it would be at least $800-$900, could be more, not sure till he got powerhead off. Sounds like alot. What do you guys think?

I'm contemplating doing it myself as it eats so much of my sales price of $2100 for boat, motor and trailer.

I've done quite a bit of auto work with removing heads, etc. and looked at a Mercury service manual. Is there anything tricky with doing it or is straight forward,removal, inspect pistons, rings, etc.

Any thoughts ?

Thanks, Jeff

Dhadley · #2 August 16th, 2005, 05:11 PM

Welcome!!

That should be the Mercosil block which is borable aluminum. The pistons are chrome plated and fairly expensive. You can install 2 sleeves and use the older (1988-94) type pistons with chrome rings.

fish4stripers · #3 August 17th, 2005, 05:13 AM

Thanks, where do you suggest buying parts?

If the buyer wont take a reduced pirce and fix it himself, I'll probably tear it apart myself to see what it looks like.

fish4stripers · #4 February 21st, 2006, 05:32 AM

Well, tore my powerhead apart. Pistons scored and need cylinders bored. SN OG 987218, In RI, Simplex machine shop says its too small. Anyone know of a machine shop that can do this? What's usual charge to bore a blind cyl? I'm willing to mail if can't find a local one.

Thanks,Jeff

Dhadley · #5 February 21st, 2006, 06:36 AM

Talk to Dan or Kurt at Mar-Fab at 800-476-1554. They can do the machine work and supply all the parts. Or can do the whole rebuild for you. This motor is no stranger to them.

fish4stripers · #6 April 3rd, 2006, 01:35 PM

Yep, Mar Fab turned my block around in 2 days. Good job. Got motor back together and boat sold on ebay in 1 week. Gotta love the internet!

Thanks, Jeff

Dhadley · #7 April 3rd, 2006, 01:41 PM

Glad it worked out! Thanks for the updates!