OMC sterndrive not moving in gear.

[Serf27]

Finally took my 1984 sterndrive out today.
First 10 minutes were fine at 4k rpm.
Then it died and would stay moving at 1800-2K rpms. Anything above and it would shortly die in about 30 seconds.
Figured it was a dirty carb.

Parked the boat for a few hours and started going back to the dock and then I heard some clatter and it stopped moving. The engine would rev up but I couldn’t move.

The prop spins in neutral and in drive/reverse, but won’t accelerate. I can also force the prop to move by hand when in drive and engine off, I can’t make reverse spin by hand.

The drive housing also has some markings where it look like internal pieces were pushed against the housing.

What does this issue sound like?
Something relatively easy with minimal parts? Or a big project?

Here’s a photo showing some stress marks on the drive.

 

[Scott Danforth]

That looks like freeze damage

 

[southkogs]

If the engine is idling fine, and will rev up in neutral; and when you put it in F or R it won't go: my first suspect is the lower unit. Intermediate and upper gear case are turning if you can idle.

It's possible you've got power problems up in the engine, but so far I suspect the lower.

 

[Scott Danforth]

Vertical drive shaft would be a thing to check

 

[racerone]

Check oil in lower unit.----Pull lower unit apart.----Clatter noises are never cheap to repair,

 

[Serf27]

It’s not freeze damage. It had no water all winter and the housing was smooth beforehand.

Yea I can idle and rev up and shift into gears but I think the drive gear is slipping.

Something may go on with the engine. Unless the binding drive gear was causing the engine to bog down.
New plugs and cap/rotor.
150 psi compression.
Drained old fuel out and filled with like 15 gallons of fresh fuel.
I suspect any old fuel would be flushed out pretty soon.
The wires haven’t been changed in who knows how long and the carb hasn’t been cleaned in 4+ years.
I am hoping that is the cause of bogging down.

I tore the drive apart just now.
The propeller shaft seems to spin ok.
The “vertical shaft”..? Doesn’t seem like it spins well. As if it’s jumping teeth or something.
I removed the bolts holding it in but it will not come out.

The oil in the lower unit is pretty much brand new. I filled it with gear oil last year and never ran the boat.
I drained it right now too, and some water came out and then the gear oil followed but it was dirty and grayish in color.

Looking at the parts diagram, I suspect these 2 gears are my issues.
https://www.ebay.com/itm/2929433586...sUQ7sCKS_6&var=&widget_ver=artemis&media=COPY

Here is a photo of the shaft that spins but feels like it’s jumping teeth.
This shaft also has up and down play of about 1-1.5”.

Thanks all.

 

[southkogs]

Take a look at your drive shaft in the upper gear case. That's the one that receives the shaft in your photo.

The gears in your link are outboard gears, I believe. They don't work for your Sterndrive.

With your lower off, does your boat start and idle okay? If so, I'd focus on the lower.

 

[Serf27]

I looked at it the upper driveshaft in the upper gear case, the splines look in tact as do the splines on the shaft I posted, known as “driveshaft” per the parts diagram.

The 2 gears I listed is what came up when I searched the part number into eBay.
I didn’t try to start it when I removed the lower drive, but I think it will still idle ok.

The lower drive is almost fully removed now. Just have the gear cable still attached. I can acesss the lower driveshaft and propeller shaft this way, and if I can avoid removing the shift cables then that wound be good, I just came pull them out. I need to look at the manual to see if it shows how.
I think those 2 shafts and their gears is the thing to focus on because of the grinding noises and teeth skipping.

Here are photos of the diagram and drive shaft and bearing parts. 35&36.

 

[Redrig]

Here is a photo of the shaft that spins but feels like it’s jumping teeth.
This shaft also has up and down play of about 1-1.5”.

Any play of that amount is bad news. Those are very tight tolerances on those gears and bearings...... Thousands of an inch . If its moving around that much I would suspect that pinion bearing or the gears themselves are shot.

I am not sure what could even result in that much slop.

I bet when you get that vertical shaft out , you will see some serious and obvious damage.

 

[Serf27]

Any play of that amount is bad news. Those are very tight tolerances on those gears and bearings...... Thousands of an inch . If its moving around that much I would suspect that pinion bearing or the gears themselves are shot.

I am not sure what could even result in that much slop.

I bet when you get that vertical shaft out , you will see some serious and obvious damage.

The parts diagram lists the forward gear, reverse gear and pinion gear.
I’m guessing the pinion gear is on the lower driveshaft.
Maybe the forward and reverse gears are ok because the prop still rotates in either direction when put into to gear and the drive shaft has all the play and is the shaft that spins oddly?

The shifter dog clutch is also listed, but if that was bad, it wouldn’t go into gear right?
I am going to try to remove the lower drive internal parts tomorrow, but just trying to gather a list of parts I’ll need.

Thanks.

 

[racerone]

The nut on the pinion gear needs to come off to take shaft out.----I suspect major damage to lower driveshaft and thrust bearing,

 

[Serf27]

I see the nut for the shaft on the diagram. Part 31.
It looks like the prop shaft has 2 c clips holding it in. Once those 2 c clips are removed, the prop shaft slides out and I can stick a wrench into the drive to remove the pinion gear nut. Correct?

Part no6 is the one I can’t remove.
I saw a video where a guy basically had to destroy it to remove it.

 

[Scott Danforth]

you need a big C-clip pliers for the two C-clips. I used a 18" Blue-Point with a ratchet lock

sterndrive.info has good videos on the OMG stringer and they have a good assortment of parts along with a rebuild service.

 

[racerone]

# 6 should just pry out with a couple of hefty screwdrivers.-----Pinion gear has to be removed first.----Shift mechanism must be removed before propshaft can come out.

 

[Redrig]

Personally , if it were me I wouldnt worry about buying parts quite yet. That lower is probably grenaded to the point of no return. That crack/swelling on the case.... that case may not even be reusable.

I would start looking for a good used lower in the same ratio . Slap it on and go boating.

The good news is that you have a good shift cable $$$$, so that is always a great start

 

[Serf27]

I’ve got the lower drive fully removed.
Hopefully the shift cable doesn’t give too much trouble when going back together.
I need to get a bearing puller tool for the prop shaft bearing holder and long c clip pliers.
The manual does show part no6 is attached to the driveshaft, so it should all come out as 1 piece when I get the nut/pinion gear off.

There’s so many drive units online, that I don’t know which one will match up and a complete one would be ideal, but they’re all stripped down to the housing.
This is the only one I see that looks similar.

C# 321448 Johnson Evinrude Lower Unit Gearcase Housing | eBay

Find many great new & used options and get the best deals for C# 321448 Johnson Evinrude Lower Unit Gearcase Housing at the best online prices at eBay! Free shipping for many products!

www.ebay.com

No one locally wants to touch it and I’d like to use it this summer.
I’m not sure how long Sterndrive.info would take to rebuild it. Unless they have one in stock.

Here is a video I took of the prop shaft spinning and the drive shaft spinning.
I started the engine for a few seconds. The upper gear case sounds fine and the upper drive shaft was spinning fine.

I am opting for new internal parts because parts are about 4-5 days for delivery and I could be back on the water next weekend.

 

[racerone]

Don't get your hopes up !!----Don't spend any beer tokens until you have this apart !!!!----And #6 is certainly not attached to the driveshaft.-----Stop guessing !

 

[Serf27]

Don't get your hopes up !!----Don't spend any beer tokens until you have this apart !!!!----And #6 is certainly not attached to the driveshaft.-----Stop guessing !

Which part?
The lower gear case housing?

Sterndrive.info has a rebuilt unit for $1900.
It would cost $1200 to rebuild my current one but it may not be good.

 

[racerone]

Good luck with it.---I step aside.

 

[Serf27]

The lower gear case has those inner damaged markings on both ends.
I took it to a shop and they said oil would probably seep through those cracks later on and any factory bearing tolerance would be out of spec.

Here’s a complete unit.
Says for use in stringer models with 800 v6 or v8.
Some small differences and I’m not sure if mine is an 800.

1982-85 OMC Stringer 800 V6 V8 Mechanical Shift Lower Unit 3.8L 4.3L 5.0L 5.7L | eBay

Compatible with V6 & V8 800 series gearcases paired with 3.8L 170hp, 4.3L 175hp, 5.0L 305, 5.7L 350 260hp. These are the later Stringer model 800 produced during 1982, 1983, 1984, 1985. It will NOT work with a hydro assist shift, electric shift, or 400 series.

www.ebay.com