3.7L Mercruiser Carburetor Replacement

Updating my previous post about my motor not turning:
Motor turns, ignition works, fuel pump works, carb crusty.

Boat: 1987 Stingray SVC190 SS
Motor: 3.7L Mercruiser I4 (470? 165?)
Carburetor: 2 Barrel, Tag: MCM 165 1389-9564

So, my goal now is to repair the carburetor. The cost for a rebuild kit is more than I care to spend $50, and it doesn't include the power valve, float, or some other parts that need to be replaced. SO...

I would like to replace it with something more cost effective, and servicable. What carbs are recommended? Brand/Size?

Brandon

Re: 3.7L Mercruiser Carburetor Replacement

One more question. What is the difference in the long blocks between the 4 barrel and the 2 barrel motors? Can I replace the intake manifold and go with a 4 barrel carb?

Re: 3.7L Mercruiser Carburetor Replacement

Not enough difference in the long blocks to make much of a difference so yes you can put a 4BBL manifold on-if you can find one. I would use a #1409 Edelbrock marine carb also as tuning parts are readily available.

Re: 3.7L Mercruiser Carburetor Replacement

Thanks for the info. I decided to pull my carb apart and rebuild it without a kit (just a good cleaning). I used some carb. gasket adhesive to put it all back together. Put it on the boat and it runs great! I'll keep my eyes out for a new manifold, but use what I have for now.

Brandon

Re: 3.7L Mercruiser Carburetor Replacement

BrandonS said:

Thanks for the info. I decided to pull my carb apart and rebuild it without a kit (just a good cleaning). I used some carb. gasket adhesive to put it all back together. Put it on the boat and it runs great! I'll keep my eyes out for a new manifold, but use what I have for now.

Brandon

Click to expand...

FYI..getting a new intake for a 4bbl carb wont be the hard part. The hard part will be getting the oil filter assembly the changes the filter placement and allows lines to be run to the oil filter that is built into the intake.

The intake can usally be found on ebay but no one ever seems to sell that assembly and you cant get it from a parts store.

oil filter assembly


lines to cooler

Re: 3.7L Mercruiser Carburetor Replacement

That looks like it could be replaced with an oil filter relocation kit. What is the purpose of running the oil through the intake? Cooling? Would it be necessary if I'm "just replacing the intake"?

Re: 3.7L Mercruiser Carburetor Replacement

Yes the intake has a cooler built into it....and yes a suppose an oil relocation kit would work if you can add the proper plumbing that will direct the oil flow leaving the filter into the cooler and then from the cooler into the engine properly.

The big thing is, going from a 2bbl set up to a 4bbl set up you are changing the engine. You are going from 165 or 170 hp to at least 180hp and depending on the 4bbl carb you can get 190hp. This also changes your WOT from 4200-4600 to 4400-4800 rpm. You are going to need the better lubrication the cooler provides and the 4? heat exchanger but that?s another issue and discussion in its self.

The intake and carb is the only real different between each hp rating for this engine. You can get 165,170,180 and 190hp versions and they all have the same specs for all the internal parts but different intakes and the larger intakes require the oil cooler and more oil. I would suggest if you?re going to do it go all the way to limit the amount of potential problems.

The 190hp version used a slightly different Quadra jet then the later 180hp versions but that?s all I know. It is very difficult to find sound information on them and i find the info a little shaky my self but have yet to prove it wrong.

If you can get a good result by making an oil assembly that accomplishes getting the oil through the filter and to cooler and back to the block, by all means pleas post how. I have had a ton of people ask me about the oil assembly so I am sure it will be welcome information.