Alpha Gen II upper - repair or replace?

[DickB]

The gears in my upper gave out at the end of Friday's AOTH run. Boat and drive are 11 years old with about 560 hours; 18C with 350 MAG. In addition to the gears, the bearing on the driving gear is shot. I haven't examined the driven gear assembly yet. I'm assuming that I would really need to do a complete rebuild of the upper.

My question is to rebuild myself or replace with an already-rebuilt or new upper. I've worked on my own cars extensively, but never on an outdrive. It looks like some specialty tools are needed. I've priced a rebuild kit at about $800 versus $1200 for a rebuilt unit, and Sterndrive Engineering has a replacement for about $800. I'm leaning toward the latter.

I would appreciate any advice on doing this myself versus buying a new or rebuilt unit. Also on parts sources, and any experience with Sterndrive Engineering equipment..

What if anything should I do with the lower, given that it may have been contaminated with particles from the upper?

[Planetwarmer]

I guarantee there are some particles in the lower unit. You might aught to disassemble the lower and clean/inspect that as well.

[gcarter]

You can get a new SEI upper and lower for about $1200.00 w/a three year warranty.......
I went that route on the Minx and was very happy w/it.
You could still fart around w/the old one if you wanted to.

[VetteLT193]

merc makes a heavy duty gear set you might be better off with.

Another idea is to buy the whole SEI drive (1200 I think?) and sell your good lower.

[glashole]

what would the conversion to a bravo 1 run?

[BUIZILLA]

Another idea is to buy the whole SEI drive (1200 I think?) and sell your good lower. and keep your good lower...

[CaribouLou]

SEI and keep the lower as a spare.

[DickB]

Yes, SIE upper and lower and keep mine as a spare is where I'm leaning. On closer examination, I see a lot of metal has been chewed away from the inside of the upper housing, so I don't think it should be reused. So a rebuild is out of the question. I took a chunk out of my skeg years ago, and "fixed" it with a Skeggard, so I doubt that my lower is worth much as is. Thanks all for the advice.

Don't think I want to do a Bravo. Have considered an Alpha SS, but do they bolt up to an Alpha Gen II bell housing?

[Planetwarmer]

Isn't an Alpha SS the same as the standard, except for the lower is a couple of inches shorter?

[MOP]

Don't think I want to do a Bravo. Have considered an Alpha SS, but do they bolt up to an Alpha Gen II bell housing?
Rootsy can tell you how it is done, does require some machine work. Good move buying a complete new drive with a good track record and a very good warranty!

[DickB]

I need additional help on gear ratio for this Alpha replacement.

My99 Classic 18 came with a 350 MAG (300 hp), Alpha Gen 2 1.62 gear ratio, and Mirage Plus 23P. I spoke with tech support at SEI, and he was surprised at that combination - even questioning whether I had read the ratio correctly. He asked why I was replacing the stern drive, and I said gears in the upper gave out. He said the 1.62 is not recommended for 300 HP, and recommended that I go with a 1.47 and different prop. He said they even recommend to customers with 200 or 250 HP to do this.

I would like to get more opinions on this. Is a 1.47 the way to go, or stick with the 1.62? If I switch, what prop would I need to run with the 1.47? I am also interested in what ratio others have in the same or similar boats.

[gcarter]

Alphas of a few years ago were 1.5/1....time goes by and manufacturing process change, so now the standard is 1.47/1.......esentially the same thing.
Your existing ratio, I would imagine was for a four cylinder to generate more torque to the prop. But such a ratio means there's a larger difference in gear size and acorresponding weakness.
My Minx originally had a 1.5 ratio Alpha I, it broke, I replaced it w/one of the earlier SEI 1.47 drives. It performed well w/a 15.5" diameter X 22" pitch Hydro Q4.

[VetteLT193]

I need additional help on gear ratio for this Alpha replacement.

My99 Classic 18 came with a 350 MAG (300 hp), Alpha Gen 2 1.62 gear ratio, and Mirage Plus 23P. I spoke with tech support at SEI, and he was surprised at that combination - even questioning whether I had read the ratio correctly. He asked why I was replacing the stern drive, and I said gears in the upper gave out. He said the 1.62 is not recommended for 300 HP, and recommended that I go with a 1.47 and different prop. He said they even recommend to customers with 200 or 250 HP to do this.

I would like to get more opinions on this. Is a 1.47 the way to go, or stick with the 1.62? If I switch, what prop would I need to run with the 1.47? I am also interested in what ratio others have in the same or similar boats.

1.62 was the old high altitude drive. Merc doesn't offer the 350 Mag / 300 with the 1.62 anymore, only the 1.47.

So... where do you live?

[DickB]

Minnesota - not high altitude. Wonder why the boat came with this drive? I bought it in Minnesota, IIRC from the original owner.

[VetteLT193]

Minnesota - not high altitude. Wonder why the boat came with this drive? I bought it in Minnesota, IIRC from the original owner.

You never know I guess. Donzi could have had a leftover package and just put it in your boat.

You pitch / drive makes me have a guess you are running pretty high RPM's. what is your full throttle RPM?

I'm asking because I suspect you can go to a 1.47 ratio and keep your current prop. you'll lose some RPM (the ratio difference is roughly equal to 2 inches of prop) so 400 RPM, but if you are maxed out (i.e. over 5000 RPM) you may not lose as much. Last I checked Merc specs the 350 Mag to be propped at 4800 RPM Max. with a top end range of 4600-5000.

[DickB]

I'm running right at 5000 RPM (or was!) and the specs in the manual accompanying the boat says 4400-4800 for the 5.7 but 4600-5000 for the 350 Mag MPI, which I have. But I agree, dropping a few hundred or so RPM would probably be a good thing. I actually also have a labbed 25P Mirage Plus prop, and it does run a hundred or so RPM less than the stock Mirage Plus 23P and gives an MPH or two more.

[DickB]

I decided to go with the 1.47 SEI. It arrived today and I got it installed and splashed the boat. I am paranoid now, so the sounds and vibrations coming through the hull seemed different than before. I suppose that is to be expected with a new drive that has not been broken in. The sound - which appeared to be coming through the hull, not the stern - seems to have subsided in just the 10-minute ride from boat ramp to home. It was subtle to begin with. I have a 5- and 10- hour break-in regime to go through, and hope to do so by the week end. Will report back later on any changes in performance over the 1.62.

Thanks to all for the advice and comments. This forum, that is all of you, are a great resource.

[MOP]

They buz when new while the gears break in, bothered George at first. It will quiet down, they cut their gears differently and seem to last longer then the Merc's.

[gcarter]

Mine whined for about 10 hours, or I got used to it......

Whichever it was, it didn't matter after about 10 hours.

[DickB]

I've got just over 5 hours break-in. Everything was fine, but found out as I was docking that reverse gear won't engage. Neutral and forward are fine. Reverse was fine. With the engine off, I pulled the throttle/shift lever all the way back and spun the prop by hand - it still would not engage. Any suggestions?

[gcarter]

Did it ever work?

Alphas have that funny shift shaft that runs to the lower....
The way it's installed has to be right (correct).

[DickB]

Yes, it was working fine.

With my wife's assistance, I observed the shift lever in the lower unit while she rowed through F - N - R. It appears that the amount of angle from N to R is considerably less than N to F. I think the lever is just not being pushed far enough for R to engage. So I assume I have some kind of linkage problem. I seem to remember from when installing the unit that the degrees of travel was equal for both F and R.

I have both a Clymer and Seloc repair manual, and neither seems to cover shift linkage - at least, I haven't found it yet.

[gcarter]

I seem to remember you can make that adjustment on the shift plate on the engine.
It's been awhile......
There're two set screws that lock the rear shift cable. You might loosen both and see if you can get it into reverse with a pair of pliers on that cable end.

[mrfixxall]

Dick, all drives are not the same and you may have to re-adjust the shift cable..remove the cable going ti the transm housing, the 2- 1/4'' nuts and remove the cable,give the rear of the 2 a couple turns in the direction you need to go..slide the cable back on and shift it into reverse and spin the prop and isted to the ratchiting sound and re=adjust from their..

[Planetwarmer]

+1 on adjusting the cable. Mine is located on the starboard side of the engine.

[DickB]

OK, I removed the remote control shift cable and operated the drive shift cable by hand. Even with the drive shift cable pulled to its max, the 90 degree lever arm on the lower unit barely moves from N to R position, and the propeller freewheels with no ratcheting. SEI tech support recommends pulling the outdrive to isloate the problem.

I discovered after the fact that there is a special tool to hold the shift slide in the gimbal/transom assembly in place while the outdrive is attached, as it is free to pivot on the cable end. I wonder if my problem is there? Odd that it worked, and now doesn't.

Looking for ideas still, before I pull the boat out of the water and pull the outdrive.

[mrfixxall]

OK, I removed the remote control shift cable and operated the drive shift cable by hand. Even with the drive shift cable pulled to its max, the 90 degree lever arm on the lower unit barely moves from N to R position, and the propeller freewheels with no ratcheting. SEI tech support recommends pulling the outdrive to isloate the problem.

I discovered after the fact that there is a special tool to hold the shift slide in the gimbal/transom assembly in place while the outdrive is attached, as it is free to pivot on the cable end. I wonder if my problem is there? Odd that it worked, and now doesn't.

Looking for ideas still, before I pull the boat out of the water and pull the outdrive.


when you pulled the drive did you have it in forward gear?? if not put it in forward gear, pull the drive and make sure the drive is in forward gear..if you turn the prop shaft while installing the drive it will pop out of gear then when you slide the drive into place the 2 main and female feet that's locates where the speedo is attached to the drive will no be aligned..

If this is the case the drive will not go into reverse and sometimes stay into gear even if the shifter is in neutral..

[DickB]

Verified by inspection that the male and female parts are aligned properly. Everything worked for 6-8 runs and 5+ hpurs over a week's time.

[DickB]

I pulled the outdrive and the problem is in the lower unit - it just will not shift into reverse. It's going back to the manufacturer for warranty work.

[DickB]

I got the lower back today and got it installed. So far so good. There was a form letter with it with check boxes for various failure modes such as Impact, Lack of lube, Overheated, etc. Mine had "Other" checked, with "Shift assy. error" handwritten in, plus "Replaced seals, shift assembly, and water pump".

[gcarter]

Hopefully there'll be no more issues w/it.

[Planetwarmer]

At least it is under warranty for a few years! Now you can see how high you can jump your boat or see how many skiers she'll pull!:cool: