salt water in single cylinder

Scott06

Scott06

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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?
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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

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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

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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…,
 
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beruken

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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…,
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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.
 
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beruken

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Is there any way to verify it is actually a mercruiser and not stock GM build?
 
Scott06

Scott06

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beruken said:
Is there any way to verify it is actually a mercruiser and not stock GM build?
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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
 
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beruken

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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

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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.
 
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nola mike

nola mike

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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.
 
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beruken

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Lou C said:
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.
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I hear ya Lou. They have a sale price going from 2.4k to 1.7 rn What they say sounds good but you never know. Just don't want to dump another 3.5 k into it bc you don't get that money back and I am tired of working on stern drives. Haven't been able to find anyone regionally that does engines either. Time for an outboard. Been seeing more of newer cabin cruiser style boats with outdrives. Single ones too. Outta my price range though!
 
Lou C

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I would look at Marine repair shops on the South Shore of LI, there are many there that I’m sure do inboard repowers I’d ask them who they use…what you need is nothing exotic just a 4.3 Chevy Vortec! Outboards are easier IF you start with a fairly new one but to do a complete repower is VERY costly.
 
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kd4pbs

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If you go with a bulk rebuilder, search deep for reviews. None of these places will create bad reviews, but they are notorious for inflating their own ability with fake positive reviews. If you read a bad review, you can trust it.
Outside of a crate engine from GM, find a local shop who rebuilds engines.
These bulk rebuilders will notoriously do things to cut corners that are janky at best. Their version of "good enough" means that the engine will probably last just long enough for the warranty to expire.
 
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