[spareparts]

there were a lot of issues with them, but most were fixable and easier for mechanics to blame the engine rather than figure it out.

Rough idle: its a big honking 4 cylinder, what do you expect? Actually it can be smoothed out with the right tuning and posible carb change( the mercrab only had one idle mixture screw for both barrels)

Charging system: yes its expensive, they gave problems because the regulator that mercruiser used created a lot of heat by running the excess voltage to ground, if you have to replace the regulator, use the rapair regulator, its a true on/off type regulator that doesn't create as much heat, but if you really have charging problems( and if you have the room) put the altenator conversion on it

Hard to start/flooding problems: most of this can be attributed to the Mercarb( made by Nikki in Japan), its a cheap copy of a Rochester 2BBL, the early mercarbs were calibrated use Japanese fuel blends(they offered a water cooled fuel linie to help with vapor locking), later versions were better but still were not as good as a Rochester, I converted a Rochester off of an old 888 Mercruiser to work on a friends 3.7, it cranked easier, idled smoother, never heat soaked(thought about putting the water cooled fuel line on it but didn't need it), the engine ran better all the way throught he range, never checked fuel consumption( i doubt it was much difference), the 4BBl Rochester was still the prefered set up(488/485/190)

Cooling system problems: early versions had a 3" heat exchanger, the later 4" was much better

Elbow/riser gaskets: when they changed to the aluminum manifold and cast iron riser, the gaskets would not seal, allowing antifreeze to leak into cyl #4, had a lot of these sent back to Mercruiser under warranty, they updated teh gasket to a better material, haven't had any problem after that, the risers do need to be replaced often if used in salt

Parts are hard to find, and expensive: no arguiing this one, a lot of stuff on this engine were Mercruiser only, I've replaced the pistons with 460 Ford with good luck( they do rattle a little because there is no pin offset as needed in an inline engine), never found a bearing cross over, gaskets are now available aftermarket

Camshaft seals leaking: ever had antifreeze leaking out the bottom front of the engine? its coming out of the weep hole, its not that bad of a job to replace the seals, but sometiimes the cam seal surface is worn, requiring a speedy sleave, seen lots of people plug up the weep hole and didn't worry about it till they got antifreeze in the oil

All this being said, i still liked these engines, my old roommate had a 3.7 in a 17 Stingray, we got that boat running 53 on radar, not bad for a 4cyl, we hurt a lot of peoples feelings with V6's and some V8's. I highly recomend replaceing the points with an electronic conversion, and setting the timing back to 5 degrees( (an early service bullitin).

Any one got an old 3.7 laying around they don't want? My old roommate( sold his original Stingray years ago) has found another Stingray to rebuild, its got a 3.0 in it, he's missing that power of the 3.7, would love to find a 180-190 hp version