Alpha One outdrive issues

[Cptkid570]

Hey everyone..

1985 26? Searay. 5.7 liter motor with Alpha 1 outdrive.

Had the boat out over the weekend and when trying to bring the boat up to speed, I blew out something in the outdrive. Boat now won?t move.

I will be taking it apart, but as I sit at work, unable to work on the boat, I wanted to ask some preliminary questions?.

The engine revs up, prop doesn?t turn at all, shifter works, looked under the outdrive and appears to be shifting properly, so it?s not the cable. It?s not a spun hub, prop doesn?t move at all.

Here is the clincher ? the impellor isn?t pumping any water into the engine at all, so it?s not spinning? Does the fact that the prop won?t turn and impellor won?t turn give you guys any indication at all of what it could be? Upper drive, lower drive, something with the shift mechanism inside?

 

[Bondo]

Re: Alpha One outdrive issues

There's Only a couple of things it Could be,......

The Engine Coupler,......... Was there a smell of Burnt Rubber,......
If Not,... That's Probably Not it........

The Top Gear Set in the Drive is a Possibility......
Or,......
The Vertical Shaft in the older Alphas has an O-ring groove near the Top,......
They're known to Shear the Shaft at the O-ring Groove........

 

[Don S]

Re: Alpha One outdrive issues

Sounds like the splines in the coupler are gone. Look at the back of the engine for metal shavings around where the shaft goes into the coupler.
Once the shaft doesn't turn, the water pump won't turn.
You can start the engine and see if the shaft is turning, if it is, see bondo's reply.

 

[Cptkid570]

Re: Alpha One outdrive issues

Thanks guys... I forgot to mention that the shaft is turning at the back of the engine, so the coupler is ok.. no smell of rubber...

My plan is to drop the lower part so that I can see the vertical shaft and test the lower (just by turning the shaft).. if those look ok then I'll take off the upper...

I just put a reman engine in.. and I was trying to get up on a plane when this happened.. I know the alpha one is rated up to 300hp, and I'm guessing that since the engine was probably bored out and has flat top heads, that I'm probably a little above the 260 hp (at least that's what I'd guess)...

So, it will be interesting to see what gave out...

 

[Don S]

Re: Alpha One outdrive issues

Pull the top cap off the outdrive and look at the gears............ Probably smooths, not gears.

And look for metal shavings around the coupler, you wouldn't smell rubber if it went that way, and there might be enough friction to turn the shaft a little bit.

 

[Cptkid570]

Re: Alpha One outdrive issues

Look at the "smooths" hahaha I like that..

I'll check into it. To be honest, I've recently pulled that engine twice (pulled the old, installed the new, then had to pull it out again to change the Y-pipe). I'm kinda hoping it's not the coupler and I don't have to pull the engine again, however, the coupler is definitely less expensive than the outdrive.

I guess a broken vertical shaft would be a relatively easy repair, I'd just have to drop the lower and I could change the impellow while I'm in there...

On a positive note: the engine has enough power to rip up the outdrive! hahaha

I'll keep you posted on what I find.. I probably won't have a chance to work on it until the weekend though.

 

[wca_tim]

Re: Alpha One outdrive issues

I just had the same thing happen... Was the lower drive shaft, sheared right at the o-ring groove. It turned out to be significantly easier to get a new lower unit than to tackle the drive shaft. I will likely replace the shaft / rebuild the lower unit later, but for the 700 I gave for a new lower unit, couldn;t really justify the time, energy, tools and parts it would take to do the lower right. Note that I don't have much (ok pretty much none) with mercruiser outdrives, but I'm pretty handy and was even trained as a machinist and mechanic some years back... My understanding on the rebuild for the lower unit is that the prop shaft has to come out, etc... have a feelin once inside there would be more to do...

I bought the lower unit from SEI. I got it in two days and it just about fell on... even came with water pump installed. Have only had it out for a short run this evening , but seems to be doing great. I also switched props. the older one I had on there had pretty much a solid hub. went to one that would have a greater chance of breaking the prop hub rather than the drive shaft. Also noted that the replacement lower's shaft did not have the o ring groove and apparent weak spot.

Hope this is helpful.

 

[peacekeeper6]

Re: Alpha One outdrive issues

i vote gears, same thing happened to me. Smooth gears a runnin...

 

[wca_tim]

Re: Alpha One outdrive issues

as others have posted, sounds like either gears of driveshaft. Let us know what you find.

I drained the lower unit lube to check for metal, etc.. if pieces of gears come out, probably upper gear box, if clean, probalby lower shaft. If your lower unit is the original 85, you have the shaft with the o-ring groove. Apparently it was very common for them to break, and the reason it was changed to a solid shaft later. The replacement unit I bought has the solid shaft in it. When I got the boat home after it crapping out, I:

1. checked for metal in the gear lube, nothing

2. took the cover off the upper unit, looked very good,

3. removed the drive unit and then separated lower and upper, looked OK EXCEPT for the minor detail that the splined part of the lower drive shaft was "missing" Some gentle tapping removed it from the upper assembly.

Here a couple of pictures of what the shaft pieces looked like on mine. sheared cleanly on the o-ring groove.

Hope this is helpful. Cheers!

 

[Cptkid570]

Re: Alpha One outdrive issues

Hey guys,
Thank you all for your responses. It turned out the my upper gears were "smoothes". I started another thread as to where I'm going to go from here...

Basically I want to make sure my lower is good..if not, I'll replace everything.. if it is, then I'll replace the upper.