salt water in single cylinder

Scott06

Scott06

Admiral
Joined
Apr 20, 2014
Messages
7,123
beruken said:
So I have a line on a cheap 2003 supposed mercruiser 090 block running engine, no manifold. Does the 090M stand for marine. How can I tell if it is marine and not just GM?
Click to expand...
090M is for metric. For some reason they used metric fasteners on some of the 4.3 blocks... in true GM fashion only some of the threads are metric- starter bolts, flywheel cover, and front/side motor mounts. I bought about $40 worth of SAE bolts to convert when I did my repower.

If you are buying a complete used engine doesn't make any difference, only when you are mixing and matching parts is it an issue

Never found an answer as to why they mixed metric and SAE threads on the same block. I can understand one or the other but both on the same block makes no ducking sense
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,341
There are no “marine” blocks or heads only add ons like the head gaskets, core plugs etc. the M refers to the us of some metric fittings. In that case if you use it be careful with threading in fasteners in fact you might want to buy an SAE/Metric thread chaser set so you can check them first!
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,341
If you wind up going with it & still have those one piece exhaust manifolds it’s a good time to ditch them for the 2 piece conversion. Barr marine makes a nice one check out Lighthouse Marine in Riverhead…,
 
B

beruken

Petty Officer 2nd Class
Joined
Oct 26, 2013
Messages
150
Lou C said:
If you wind up going with it & still have those one piece exhaust manifolds it’s a good time to ditch them for the 2 piece conversion. Barr marine makes a nice one check out Lighthouse Marine in Riverhead…,
Click to expand...
Thanks. Yes, I have new 2 piece on my baddy rn. It is just the long block so I have to bring everything over. My only concern right now is the compression. That motor was an MPI with electronic ignition. I had carb and distributor with thunderbolt ig. I assume distributor will drop right in.
 
B

beruken

Petty Officer 2nd Class
Joined
Oct 26, 2013
Messages
150
Is there any way to verify it is actually a mercruiser and not stock GM build?
 
Scott06

Scott06

Admiral
Joined
Apr 20, 2014
Messages
7,123
beruken said:
Is there any way to verify it is actually a mercruiser and not stock GM build?
Click to expand...
It will have a mercrusier serial number tag riveted by the starter

Mercuriser buys gm base engines/ long block and builds them out so it is just a gm truck engine with minor tweaks
 
B

beruken

Petty Officer 2nd Class
Joined
Oct 26, 2013
Messages
150
So I found a reman with a decent sale price ongoing but want to know if anyone has experience or knowledge of United Engine I believe out of California but not sure. They don't post their corporate address.
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,341
I’m very suspicious of ANY of those places. Try a local rebuilder, ask local marine mechanics for recommendations, who do they use. The idea of sending off $3500 to a place I've never seen people I don't know is unsettling. It's too bad you can't get any more new 4.3s, the only GM marine engines you can still buy new AFAIK are the 3.0 4 cyl and the 5.7 V8.
 
Last edited:
nola mike

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,682
many on here have had luck with Michigan motorz. I haven't purchased an engine from them, but have bought a few parts, and spoken with them about technical questions, they were very helpful.
 
You must log in or register to reply here.
Top