'85 OMC 3.8l 4 barrel specs

[t_south91]

Does anyone know the specs on this motor??

Just acquired a 1985 sea sprite 180 xl and it has a 3.8l OMC 4 barrel in it. Getting it checked out next week but wondering if I could just swap it out for 4.3 or maybe put a 5.0 in it. Would either of those fit??

Thanks for the help!!

 

[MikDee]

Re: '85 OMC 3.8l 4 barrel specs

Well the 3.8, and the 4.3 have the same exterior dimensions, so that would work. The 5.0 might drop right in, as long as the engine mounts are in the right place? On a car, the engine mounts do match up between the 3.8, & 5.0, I know I did it on my 79' Chevelle wagon.

 

[Scott Danforth]

Re: '85 OMC 3.8l 4 barrel specs

do a bit of research on here. this issue comes up often. the crank is different between the 3.8 and 4.3. there is the elusive 1985 only 4.3 with the 2-piece crank, however you may be able to find bigfoot easier

there are also companies that make custom couplers.

a 5.0 or 5.7 would fit, however you would be dropping in a complete motor/exhaust.

 

[MikDee]

Re: '85 OMC 3.8l 4 barrel specs

do a bit of research on here. this issue comes up often. the crank is different between the 3.8 and 4.3. there is the elusive 1985 only 4.3 with the 2-piece crank, however you may be able to find bigfoot easier

there are also companies that make custom couplers.

a 5.0 or 5.7 would fit, however you would be dropping in a complete motor/exhaust.

Thanks Scott, Live, & learn! Custom couplers too? Interesting

I had one of these start to fail, from age, & wear, & tear. The boat would run fine with a light load, but the more you loaded it down, the more it would slip! It was a 1972 Wellcraft Airslot 18.5' bowrider 165hp Merc. I got the boat cheap, (engine seized), I couldn't free it up :distress:,
So, gave it up, and rebuilt it. It then ran like a raped ape, but still had this coupler issue,,, if I'd have known more about boats, I would have put a new coupler on it while I had it apart ,,, after awhile, I sold the boat.

 

[t_south91]

Re: '85 OMC 3.8l 4 barrel specs

Thanks for all the help so far!

I love the thought of putting in a 5.0 and just having that thing haul *****!!
Just something to think about I suppose. I'll keep an update after I have a visit to the shop and see what they say about it.

On another note...anyone know where the trim pump reservoir is?? I think its out of fluid...

 

[Bondo]

Re: '85 OMC 3.8l 4 barrel specs

Thanks for all the help so far!

I love the thought of putting in a 5.0 and just having that thing haul *****!!
Just something to think about I suppose. I'll keep an update after I have a visit to the shop and see what they say about it.

On another note...anyone know where the trim pump reservoir is?? I think its out of fluid...

Ayuh,.... Welcome Aboard,..... Is yer Outdrive, the Stringer, or the Cobra drive,..??

 

[Howard Sterndrive]

Re: '85 OMC 3.8l 4 barrel specs

I love the thought of putting in a 5.0 and just having that thing haul *****!!
On another note...anyone know where the trim pump reservoir is?? I think its out of fluid...

OMC had a 5.0 one year that was rated 175HP, that's 10HP Less than the 3.8/4V

trim pump is mounted starboard side of engine behind the exhaust manifold, above the starter motor

 

[gottaboatnow]

This might be late in coming, but I took my coupler and my new flywheel to a machine shop. They drilled new holes in the coupler between the existing hole pattern. That Stainless Steel is plenty thick enough to handle the job since it gets sandwiched between the Crank and the Flywheel anyway. They also trued up the coupler, which was not concentric to begin with, probably from day one. Cost about $100, but had it back the same day. I would trust the original coupler, even with swiss cheese holes in it, before I would trust one of the rubber versions I've seen for sale as "adapters". Just my two-cents, for what it's worth....