1987 Mercruiser 4 Cyl...thanks

Thanks guys it was a bad tube in heat exchanger Now this motor is a 224/165hp mercrusiers does anyone know what type block and motor it ...my 3.0l glastron says gm right on the block.and i was able to get rings and rod bearings thru and auto parts wharehouse...someone told me its a ford but i'd like to find out for sure because i want to find some push rods for it......It's serial number is b600388 and model number is mcm165224

 

Mercruiser used the 3.7 GM block and stuck a Ford head on it, creating come confusion. The push rod you want is part number MELMPR308.

 

That engine block was made by Merc from a clean sheet, nothing GM about it at all except later versions used Delco starters
GM 3.7 is 5 cyl
You also need a range of pushrods as that is how you adjust the valve clearance.

 

It is a merc block, designed by them. It was thought that they could design an engine better for their needs, a very large four cylinder. Larger than the iron duke from GM, with more torque. The block, crank, cam, and accessories are their design, but most of the other parts are from Detroit company's. The bell-housing is GM as is the starter. The cylinder head, rocker arms, pistons, rods are from a Ford 460. So it is basically half of a ford 460. They had quite a few problems with them and I think it was less trouble and cheaper to start using GMs 4.3 engine. They have a huge following in circle track where they run on alcohol and have stroked them to even greater size. Steve

 

The engine was designed way back in Mr K's days
I would say quiet reliable
The permanent magnet alternator was not great other than that they had no issues
I would still have one in a boat even today if it was late 4" heat exchanger one.
But i would take it apart and get it balanced then put it back in

If you want to see what Merc can design look a the new twin turbo V8

 

coincidentally, my 1st post on this forum today involves a 1987 mercruiser 4cyl. I'm debating repowering with something much smaller, since I only need very slow speeds, however this thread interests me, and I would like to know if the Mercruiser I have is the one referred to here.
How do I find out what I have here?
where are the applicable serial nos. located?

 

which side of the engine is the exhaust manifold