Neede help identifying OMC stern drive

[Dunromin]

I just bought a 1984 Tempest 4cyl with a model 983486 stern drive which came to me in pieces due to a seizure.
Not sure I want to tackle that, since I have zero experience. I plan on searching for a used replacement, and may have a line on one, a model 982740, which I think is the previous years model. Can anyone tell me if they are interchangeable?

 

[southkogs]

I don't think those are model numbers. Probably part numbers on the cases. Look inside the engine bay for a number tag. It should read something like "252STHRCRA 1984."

Since it's in pieces, do you know that your engine turns free? And then do you know if the upper gear case turns free (by hand or using a tool)? If so, you may just need a lower gear case.

Also: little bit of a gut check. The OMC Stringer isn't the worst thing ever invented, but it's old (read that "obsolete"), parts are getting harder to get hold of, and they can be kinda' finicky (meaning you maintain 'em almost as much a boat with 'em). Before you put a lot into this, make sure you want to own a vintage drive system. You can not repower this boat without a complete rebuild of the transom.

 

[Dunromin]

I don't think those are model numbers. Probably part numbers on the cases. Look inside the engine bay for a number tag. It should read something like "252STHRCRA 1984."

Since it's in pieces, do you know that your engine turns free? And then do you know if the upper gear case turns free (by hand or using a tool)? If so, you may just need a lower gear case.

Also: little bit of a gut check. The OMC Stringer isn't the worst thing ever invented, but it's old (read that "obsolete"), parts are getting harder to get hold of, and they can be kinda' finicky (meaning you maintain 'em almost as much a boat with 'em). Before you put a lot into this, make sure you want to own a vintage drive system. You can not repower this boat without a complete rebuild of the transom.

I believe they are model numbers. 983486 is on a plate attached to my outdrive, and the other is on the plate of one I have seen for sale. The ball gear turns clockwise only, (stiffly) and not anti clock, is that normal?

 

[hugh g]

I just bought a 1984 Tempest 4cyl with a model 983486 stern drive which came to me in pieces due to a seizure.
Not sure I want to tackle that, since I have zero experience. I plan on searching for a used replacement, and may have a line on one, a model 982740, which I think is the previous years model. Can anyone tell me if they are interchangeable?

Before you proceed you should make sure that the transom, stringers & deck are solid before you sink money into an outdrive only to discover that the above is full of sawdust. That boat is almost 40 years old.

 

[Scott Danforth]

84 is a stringer. Behind a 4 cylinder is a stringer 400, behind a v6 or v8 is a stringer 800

You need a 1981 to 1984 stringer 400 (also covers 1985) these are silver. The 1978 -1980 hydromechanical shift are white. Will not work PERIOD

That shift cable is $900 dont damage it

 

[Scott Danforth]

Having been there and done that, i would return the boat to whome you bought it from and give them an extra $100. It will save you money

 

[Earl Cordova]

The OMC stringer was a really poor design.
It was discontinued in 1987 because Mercruiser's patent expired.
I had a 1986 OMC and gave up on it in 2005 because a lot of parts were discontinued
and what you could get were stupid expensive.

It is really too bad since I liked the boat it was in.

 

[southkogs]

I believe they are model numbers. 983486 is on a plate attached to my outdrive, and the other is on the plate of one I have seen for sale. The ball gear turns clockwise only, (stiffly) and not anti clock, is that normal?

Nope. 983486 is the part number on the upper gear case for a Stringer 400. It's not your outdrive's model number. I think - but don't know - the other part number is a hydromechanical lower gear case; which is a different drive than you have.

If the upper is rotating clockwise relatively easily, then most likely it's good. If the engine rotates, then that makes your primary suspect the lower unit. Make sure you're paying attention to what everyone is saying about being a Stringer owner. - I actually like the Stringer drives. They have some benefits, but they are finicky.

 

[Dunromin]

84 is a stringer. Behind a 4 cylinder is a stringer 400, behind a v6 or v8 is a stringer 800

You need a 1981 to 1984 stringer 400 (also covers 1985) these are silver. The 1978 -1980 hydromechanical shift are white. Will not work PERIOD

That shift cable is $900 dont damage it

Mine is silver, and thanks for that gem re the shift cable, I will be treating it with reverence going forward.

 

[Scott Danforth]

BTW, you can rebuild your drive. go here for info / videos / exploded views / parts. pretty much the last company that caters to the Obsolete Marine Co drives.

OMC parts *Exploded view drawings *Outdrive repair help video

Exploded view OMC 800 parts drawings. Designed to help boating enthusiasts performing repair work on 400-800 outdrive lower units and Cobra sterndrive gearcases.

www.sterndrive.info

 

[Dunromin]

Nope. 983486 is the part number on the upper gear case for a Stringer 400. It's not your outdrive's model number. I think - but don't know - the other part number is a hydromechanical lower gear case; which is a different drive than you have.

If the upper is rotating clockwise relatively easily, then most likely it's good. If the engine rotates, then that makes your primary suspect the lower unit. Make sure you're paying attention to what everyone is saying about being a Stringer owner. - I actually like the Stringer drives. They have some benefits, but they are finick

Well, lots of good info here, thanks to everyone. The engine is free, floor has no obvious soft spots, and the stringers the engine is mounted to look solid, although being covered in fibre glass, I can't see what's going on underneath. All things considered, and having a little mechanical ability, I am going to consider the POSSIBILITY of rebuilding it myself, while also looking for a good used replacement.

 

[Scott Danforth]

All things considered, and having a little mechanical ability,

that statement there says buy a boat that is only 5-10 years old, not 40 with an obsolete drive

 

[hugh g]

Well, lots of good info here, thanks to everyone. The engine is free, floor has no obvious soft spots, and the stringers the engine is mounted to look solid, although being covered in fibre glass, I can't see what's going on underneath. All things considered, and having a little mechanical ability, I am going to consider the POSSIBILITY of rebuilding it myself, while also looking for a good used replacement.

A buddy of mine had the same deal you have. He bought a 20 ft 1980 Sea Ray bowrider dirt cheap with the stringer drive in boxes. He got it running, spent a fortune doing it & after having to spend more time in his driveway working on it, he gave up on it. He actually sold the drive on CL, dirt cheap & took a beating on what he had in it. It's a shame because the boat was built like a tank, was powered by a Chevy engine & you could not hear that engine run. He sold the engine for a few bucks just to get rid of it & the hull is now taking up space in a landfill.

Moral of the story, don't buy a stringer if you want to boat instead of working on it. That drive was designed by committee.

 

[southkogs]

I'll take the counter point: my first I/O purchase ever was a OMC Electric Shift Stringer. I was pretty much clueless on sterndrives, but picked up the boat cheap. Fortunately I came here for help, and a couple of guys gave me some tips. For less than $800 I had the boat all cleaned up, and running pretty nicely.

I had to stay on top of the Stringer and be pretty religious with it. It wasn't bad, but not like the boat I have now. This Bayliner runs better and more efficiently, but the Stringer was MUCH more quiet on the water and maneuvered better at low speeds.

As long as you pay attention as you go along, you can make sure you don't get so far in that you'll lose your shirt on the boat. And sometimes, you can get a nice runnin' oldie out of the gig. Just know how far you're willing to go with it, and be ready to cut bait if you need to - then have some fun workin' on it.

 

[Scott Danforth]

I'll take the counter point: my first I/O purchase ever was a OMC Electric Shift Stringer. I was pretty much clueless on sterndrives, but picked up the boat cheap. Fortunately I came here for help, and a couple of guys gave me some tips. For less than $800 I had the boat all cleaned up, and running pretty nicely.

I had to stay on top of the Stringer and be pretty religious with it. It wasn't bad, but not like the boat I have now. This Bayliner runs better and more efficiently, but the Stringer was MUCH more quiet on the water and maneuvered better at low speeds.

As long as you pay attention as you go along, you can make sure you don't get so far in that you'll lose your shirt on the boat. And sometimes, you can get a nice runnin' oldie out of the gig. Just know how far you're willing to go with it, and be ready to cut bait if you need to - then have some fun workin' on it.

'kogs, you may have been clueless about sterndrives, however you were mechanically inclined. the OP stated they were noobs at boats and having little mechanical ability. there is a difference.

I do agree the stringer is a great drive for simply puttering along at idle.

 

[Dunromin]

I don't think those are model numbers. Probably part numbers on the cases. Look inside the engine bay for a number tag. It should read something like "252STHRCRA 1984."

Since it's in pieces, do you know that your engine turns free? And then do you know if the upper gear case turns free (by hand or using a tool)? If so, you may just need a lower gear case.

Also: little bit of a gut check. The OMC Stringer isn't the worst thing ever invented, but it's old (read that "obsolete"), parts are getting harder to get hold of, and they can be kinda' finicky (meaning you maintain 'em almost as much a boat with 'em). Before you put a lot into this, make sure you want to own a vintage drive system. You can not repower this boat without a complete rebuild of the transom.

Time for my first apology. Turns out Southkogs is right about the model numbers. The one on the engine rocker cover, (302STHRCRA), which I originally took to be the engine number, is correct for the sterndrive too. I found the correct parts drawing on the marineengine.com website under that number. In my own defence, the number I gave, 983486 is indeed given as a model number on a plate affixed to the upper gearbox, although I guess it must be just for the upper gearbox only.
I assume the engine number on the rocker cover must be for the engine/sterndrive as a unit.
I have decided to rebuild the lower sterndrive myself, and I'd like to set concerned minds at ease, I have never worked on a sterndrive in my life, but I have rebuilt the engine on a relatives boat several years ago, and have stripped/rebuilt several vintage motorcycle engines and gearboxes, plus a couple of car engines. This probably explains why I bought a 37 year old boat. I still claim "a liittle" mechanical ability when compared to someone who does it for a paycheck, but I have a decent workshop, and I'm confident I can do it with lots of advice. Sorry for the confusion.

 

[Scott Danforth]

if you can set up pinion preload on a rear end you can set up a stringer. however you do need a lot of shims.

@kenny nunez any suggestions?

 

[southkogs]

Time for my first apology.

No apologies ... guess how I learned about that number:

 

[Dunromin]

What is the best book to get to assist rebuilding a 400? And while I'm waiting for one to arrive, can anyone tell me what is involved in removing the prop shaft. It came to me with most of the internals removed, and although it will slide out a little, it will not pull right out. Is anything holding it onto the large pinion gear, or is the pinion gear supposed to pull out with the shaft? The small pinion gear is loose, since the driveshaft has been removed, but I can't see how to remove the small pinion while the prop shaft is still in place.

 

[southkogs]

You should be able to find the shop manual for your drive here: https://www.outboardbooks.com/

Dunno' about pullin' the shaft. I never dug into the lower that far.