1995 BlackMax 250HP 3.0L Carburated/Cylinder Head Installation Advice

nem0hnc

Recruit
Joined
Nov 12, 2013
Messages
1
Hi...

Just bought my first boat with a '95 BlackMax 3.0L 225HP Carburated engine which had a no start condition. I found the stator had an open coil and two CDM were shorted.

I have some experience overhauling automotive engines; however, this is my first outboard experience. While waiting for parts to arrive, I started messing with other parts of the engine, like replacing thermostats. While trying to remove thermostats, one of the bolts broke and I had to remove the cylinder head in order to drill out the bolt and install a Heli-coil thread repair kit. I have the block ready. I also purchased new bolts, thermostat, and to my surprise, this engine does not have a head gasket. It comes with o-rings.

I've never installed heads with no head gasket.

I need help with two topics:

1) Do I need to take the cylinder head to a machine shop to get it resurfaced? Is there a recommended method to clean the o-ring grooves on the head by myself?

2) When re-installing the cylinder head, should I use any type to silicone sealant? Like I said, no experience with o-ring cylinder heads.

Thanks in advance for your advice.
 
Last edited:

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
9,292
Re: 1995 BlackMax 250HP 3.0L Carburated/Cylinder Head Installation Advice

Hi there, Do you have an Mercury OEM service manual next to you while you are you working on your engine?

If not, You'll need Mercury part number 90-822900R 2 | eBay
 
Last edited:

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: 1995 BlackMax 250HP 3.0L Carburated/Cylinder Head Installation Advice

Nem0;

See my PM to you about Manual 90-822900R3.

Gerry
 
Top