Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

[tr918]

Does anyone know the horsepower rating for a 1981 3.8L OMC w/ OMC 800 stern drive? I was looking at a boat with this engine/drive combo. The owner says it is a 175HP engine. The coast guard plate on the inside of the boat says 150HP. Does anyone know the correct rating on this engine? Thanks

 

[Bondo]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

I Don't know the horsepower,......<br />But,...<br />I Do Know that you should Keep Looking........<br /><br />That's a motor that wasn't used very much,.. for very long...... Parts are next to Impossible to find,.....<br />And,... <br />That Drive Isn't much Better.........<br /><br />Find a boat with a Mercruiser, or Volvo drive,.....<br />You'll be Much Happier.......

 

[KaGee]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

As the owner of a 3.8L I can say that it is 175HP.<br /><br />If this is your first boat I suggest you look for something else unless you are very good mechanically. In '81, they still had a hydro assisted shift in the lower unit which had it's problems. <br /><br />Keep in mind that OMC is out of business. Parts for the drives are available but pricey at times.<br /><br />Bondo... True the 229 cu. in. was made by Chevy for about 4 years. I'm told it's history is linked to the 305 5.0L. Engine internals are a dime a dozen as they are the same as a 305. Castings if needed are definetly boneyard items. And.... I have solved the manifold issues.

 

[whywhyzed]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

It's 170HP with the 2 barrel carb, 185HP with a 4 barrel if Bondo hasn't talked you out of it yet...<br />I'd buy that boat before one with a Cobra drive, but Volvo or Mercruiser are def. the way to go if you are new to sterndrives.

 

[KaGee]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Hystat.... you maybe interested too.<br /><br />

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[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Thanks. I am looking for my second boat. First was a Trihull with a 65hp Evinrude outboard. I am not sure yet if I want to go I/O or Outboard. This boat had a good price tag on it. I wanted to know what I would be getting into. <br /><br />KaGee- What is the problem with the manifolds? The manifolds on the picts look different than the ones on this boat.

 

[whywhyzed]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

very nice - I have some pics saved on my pc here too that I grabbed from the net of someone else that made the same manifold conversion- used Osco as well. The OMC rear riser exhaust manifolds are very rare and dear TR918...<br />My JB weld is still holding ... season 2!

 

[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Are the manifolds problematic? Or are they just hard to find?

 

[Bondo]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Originally posted by TR918:<br /> Are the manifolds problematic? Or are they just hard to find?

No,... It's more of Impossible to Find,....And,... Most places will only charge you the Life of Your 1st Born for a set.............<br /><br />It's the Stringer Drive that's Problematic.........And Expensive to Fix......<br /><br />Please,.... Do Yourself a Favor,.... Keep Looking..........<br />

This boat had a good price tag on it.

If it's FREE,...... That's TOO Much to Pay for it................<br /><br />

Bondo... True the 229 cu. in. was made by Chevy for about 4 years. I'm told it's history is linked to the 305 5.0L. Engine internals are a dime a dozen as they are the same as a 305. Castings if needed are definetly boneyard items. And.... I have solved the manifold issues. <br />

If this is True,...... Manifolds for a 4.3l Should be a Direct Interchange..........<br />And,..... If you Needed a block,..... <br />A 4.3l could be Sleeved down to the 3 3/4" bore...........<br />Or,........<br />You Should be able to Drop-in a 4.3l,+ All the bolt-holes, Should line up...........

 

[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

How bad can the OMC 800's be? Or am I opening a can of worms? The stern drive on this has been completely rebuilt(b/c of a submerged tree). <br /><br />How frequent do things go bad on a(any) stern drive if it is not abused? <br /><br />All I know are outboards and outboard lower units. And if you take care of them they will take care of you. I thought I/O drives were similiar in dependability.

 

[Bondo]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

All I know are outboards and outboard lower units. And if you take care of them they will take care of you. I thought I/O drives were similiar in dependability.

That's Very True,................<br /><br />Except,... The Stringer Drives were of Questionable Reliability,+ Durability, When they were New,......<br />Now they're approaching 30 Years Old,+ the Manufacturer has Gone Belly Up.............<br />Aftermarket,+ Junkyards are the Only places to Buy Parts............. <br /><br />Keep Looking............................

 

[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

So you are telling me that buying an OMC 800 Stern drive of any type is a bad idea?. <br /><br />I am getting the general feeling that it would be like buying my Ford Windstar all over again..Trouble from the start! <br /><br />Thanks for the advice.

 

[fendersfender]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

i have an '85 searay with twin 3.8L OMC's (800 series)--- have had nothing but problems and they will definitely drain a wallet--my opinion is to stay away from them..........and is it true that 4.3L will drop right in to replace a 3.8L???? exhaust manifolds and everything???

 

[whywhyzed]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

The 4.3 is a fairly common swap - the exhaust ports on the heads are the same 3.8 and 4.3.<br /><br />I have a 229 rebuilt short block if anyone looking.<br /><br />Mercruiser used the 229 briefly as a MR185 with the 4BBL<br /><br />These were supposed to materialize for around $600/pair.. don't know if they did yet...<br /><br /> http://www.glmmarine.com/manifolds/images/pictures/51472.jpg

 

[KaGee]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Bondo...<br /><br />The problem is not bolting up to the engine... The problem is clearing the trim jacks. I know sombody that has a set of Merc manifolds because someone else insisted they would work. <br /><br />A early run 4.3 will bolt up. A later run 4.3 will work also, but since they used an electric fuel pump you have to modify accordingly. Either way you need a complete engine... intake, distributor and tin etc... as nothing is interchangable with a 3.8.except for the exhaust.

 

[KaGee]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

TR918...<br /><br />The 800 will run strong if properly maintained.<br /><br />1) the motor is NEVER run with the drive in any position other than tilted all the way down. Even slightly tilted, it's hard on the ball gears.<br /><br />2) Never shift above 700 RPM. <br /><br />3)keep an eye un the upper for water... if this one was serviced, should not be an issue now.<br /><br />Make up your own mind, just go into it understanding what you have. MERCRUISERS have their issues too! RODBOLT loves them cause he makes tons of money servicing them. He calls 'em "Black Anchors"

 

[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Thanks for all the info guys. I still have a few more questions. <br /><br />

3)keep an eye un the upper for water... if this one was serviced, should not be an issue now.<br />

Even after it has been serviced will the upper be an issue in the future? Are the seals/gaskets in the upper a weak link and prone to leakage? Or is it more like other lower units where if it leaks replace it and it should be fine for several years?

 

[KaGee]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

If the dude replaced the steering shaft bushing and really sealed that area good, you should be good to go.

 

[tr918]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

Thanks to all.

 

[jjnimphius]

Re: Actual Hp of a 1981 3.8L OMC w/ 800 stern drive

KaGee:<br />I take it that you replaced the original manifolds with the ones pictured. I have the 3.8l in a 1981 Grady White. Can you give the part #s you used in this conversion? <br />Thanks Very Much