Automotive Engine Base for 3.0L 181ci Mercruiser

[pjaec001]

I know there are differences in Marine and Automotive Engines and I know what those important reasons are, but I am curious as to what the automotive equivalent is to the 3.0L 181ci 4cylinder Mercruiser Engine is.
I know its a GM Motor, but cant seem to find one that matches up by any GM years, makes, or models.
Anyone here know?

I recently just replaced my starter on this and did so with the proper marine rated starter, but was curious as to what the cost would have been using the automotive one.
I also tend to need to replace the starter relay frequently and want to see if there is a difference in the marine or auto version.

[CptBill]

You'll need to get the # off the block and look it up in a cross ref. chart or just put it in the www and see what comes up. The basic block is the same it's all the add on stuff that makes the difference. Of course some blocks are a little different when you get into the bigger motors, things like 4 bolt main bearings and so on, also' most of the time they use engine platforms that are designed for trucks not cars.

[04FXdwgi]

The 3.0 / 181 was an engine used in the Chevy II Nova (was a 151 in the car), back in the 70's. Basically 1/2 of a 327 engine and some of the parts of a 327 fit. I had one in an 18' Bayliner Eagle and rebuilt it with some 327 internal parts and a hotter cam. Was a great little engine.

Pretty rare to find a good auto one these days. I would say your best bet would be to get used (but good) one from a place like fleabay or Craigslist

[Daddubo99]

The biggest difference is brass freeze plugs, and stainless-steel head gaskets and the V-8's have 4 bolt mains.

[Bt Doctur]

I recently just replaced my starter on this and did so with the proper marine rated starter, but was curious as to what the cost would have been using the automotive one.

Maybe just your life if it ever ignites and gas fumes

[DaveKamp]

Okay, so I realize this is a post from 2019... but I'll append on my notes in the event that someone ELSE searches for the same information:
------------------------------------------------------------------------
I know its a GM Motor, but cant seem to find one that matches up by any GM years, makes, or models.
Anyone here know?
I recently just replaced my starter on this and did so with the proper marine rated starter, but was curious as to what the cost would have been using the automotive one. I also tend to need to replace the starter relay frequently and want to see if there is a difference in the marine or auto version.
------------------------------------------------------------------------

Don't use Automotive parts in a marine application EVER. If you have parts failing, there's some other problem.

RE the engine's lineage:

GM manufactured only ONE type of automotive engine in this family- the 153ci four cylinder, not to be confused with the 2.5l 'iron duke' found in the Chevy Citation of the '80's, as noted above, this 153ci 4 cylinder was found in the Chevy II of the mid 60's. It was derived essentially by removing two middle cylinders from the1962 "Turbo-Thrift" (Generation 3) Chevrolet 230ci inline six. Chevrolet discontinued automotive and light truck production of the 153ci four in 1970, so you will NOT find ANY references to it in that context after 1970. ANY produced AFTER, were only by the GM Industrial division, used in generators, forklifts, chipper-shredders, street sweepers, trenching machines, irrigation pumps, etc.,

The engine that MerCruiser Marine used, was NOT a CHEVY II engine. It was not sourced through the Chevrolet division, it was sourced through GM Marine Division (Propulsion Tonawanda). GM Marine division used engine castings, reciprocating assemblies, and other internal components from the INDUSTRIAL product path, castings from Messena, Saginaw, and Defiance. They used marine-spec camshafts, corrosion resistant frost plugs, high-strength fasteners, stainless exposed (unfinishable) components and per-order elements like carbeuration, fuel pumps, alternators, starters, solenoids, flame arrestors, water temp and oil pressure sending units and even V-belts manufactured specifically for use in an explosion-proof environment.

MerCruiser purchased from GM Marine division, having them built to specification, and fitted with MerCruiser valve and tappet covers, intake and exhaust manifolds, bell housings, couplers, and engine mounts, fitted them with MerCruiser's wiring harnesses, heat exchangers, thermostat housings, throttle and shift linkage plates, to be included as a complete powerhead assembly. The 153ci four cylinder was originally referred to as the '120'.

The 3.0L was derived from the 153, but it received an increase in displacement to 181 cubic inches by virtue of
MerCruiser specifying the 4" x 3.6" bore/stroke. This engine was dubbed the '3.0', it was NEVER used in automotive applications- just industrial equipment and marine... and in comparison to it's contemporary competetors, the 153 and 181 ruled the roost. My Hyster H50H has the Ford 192, and in comparison to the GM 181, the 192 FOUR is a helpless pooch, which is why Hyster discontinued the 192 four in lieu of the GM 181 in all years after.

MerCruiser identified the 181 as the 140, and later, as the 3.0, HOWEVER, GM ceased manufacture of the 181/3.0 industrial platform around 1989, at which point, MerCruiser had purchased a large volume which it continued selling out their stock, and ramped up manufacturing their OWN engine (the 470 family) to take it's place. While it had a few troublesome spots (namely, the water cooled permanent-magnet alternator), the 470 was a lighter and more powerful propulsion package than the iron 3.0.