Mercruiser 4.2/ 200

tunafishhkg

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VM Motori, an Italian company engine that have little to no support. My friend has one on his eastern and I installed a drive shower assap when he got it. Not a lot of them around and he does not put many hrs on his but it does run good and simple to work on, just have to mail order a lot of the parts. I think like most high rev chain saw engines, any small problem can take it out so make sure to maintain and keep the SCA in the coolant checked.
 

Downeaster

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Not sure if these are still badged Cummins or not but Cummins will drop these either this year or next. I wouldn't worry about parts if I already had one but I wouldn't be repowering with one now either.
 

BillD

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Not sure if these are still badged Cummins or not but Cummins will drop these either this year or next. I wouldn't worry about parts if I already had one but I wouldn't be repowering with one now either.
the 4.2 "could be" a good example of the many reasons Cummins/Mercruiser have gone their separate ways.

200+ hp out of a 4.2 liter "lightweight" block with the slightest overload equals "poof".

Go over to boatdiesel forum, do a search on the 4.2 and read.
 

Pedlyr

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Thanks for the replies gentlemen.

What I have gathered on these engines has been confusing to say the least, pretty much the same as mentioned.

They were designed by BMW Marine and built in Italy by VM, . VM was sold to Detroit Diesel and Mercruiser bought the line. They then put it on Cummins to take care of them. This arrangement is over in a year and a half so Mercruiser will be responsible. It is a "tunnel bore". Crankshaft is in the middle of the block. Mercruiser service manual is not accurate, and I am not sure Cummins has literature on this.

I have been "'working" on one of these in a boat we have bought. There is a terrible knock in one engine so I pulled all the covers.....you can't even adjust the valves. They are all tight as a drum too. 2 cylinders are not firing. Engine has liners and individual aluminum heads. But you can't adjust the valves. Like a lawn mower...or chain saw.

This should be fun.

P.S. The outdrives are toast. But I expected that.
 
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