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Rebuilt 74 with an Alpha One Outdrive

C

Craig Bayliss

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"I just bought an 86 Four Winn

"I just bought an 86 Four Winns Liberator with a rebuilt (last season) 7.4 litre with an Alpha One outdrive. During my investigations on this boat, I found something on a Mercruiser site that said Alpha One's can only handle up to 300 HP. 7.4's, I've found, seem to range from 330 to 370 HP, am I in jeopardy of killing this outdrive with this engine. I got a great deal on the boat, now I'm wondering what hidden problem I may have bought with it. Hopefully it's just a good deal."
 
"How big is the 86? (Weigh

"How big is the 86? (Weight)
What gear ratio is the Alpha running?
Drive shower?
Synthetic drive oil?
Alpha's are rated at 300 horsepower.
You have your hand on the throttle.
I run a 330hp 454 with a regeared Alpha 1.
This power package is in a 2750 pound (dry weight) 23 foot boat.
The Sea Ray's of the late eighties that used 454 with Alpha's didn't last because the hulls were over 6,000 and the owner's tried to cross Lake Michigan at full throttle.
Back then no drive showers or synthetic drive oil.
I also use a sternjack and a two speed prop, I don't have to stand on the throttle to literally jump on plane."
 
"Merc used the Alpha One's

"Merc used the Alpha One's behind 454's for a few years until the Bravo drive came out in 88-89 range. They were given a 1.32 drive ratio to help them live with the big block torque.

I am very familiar with the Liberator, a few friends have late 80's models at my local lake. They are a well built but heavy boat for their size.

There are many happy owners of the same combo out there that have never had a problem. I'd advise doing as Mark stated...

Get a drive shower to keep the upper portion of the case cool and run synthetic gear oil. You will break the drive if you overpower it from a dead stop. A heavy boat with a 454 fully loaded and taken to WOT from a dead stop is going to kill the Alpha. They usually break right below the splines of the vertical driveshaft or the teeth of the upper gears strip. These are not jet boats so there is no need for a WOT start. Only use enough necessary throttle to get on plane. Once your moving you should be able to go WOT to your hearts content. Also, if you ever get the prop out of the water wave jumping, get off the throttle before reentry as it will also break the drive.

If the good deal on the boat is legit go for it. Just remember the guidelines and you should not have any problems with the Alpha.
HTH"
 
"Thanks for this guys, it'

"Thanks for this guys, it's a 21' and around 3500 pounds, maybe a bit more, 3750? I was actually able to get in touch with the previous owner (previous to the guy I bought it from) and the drive is OK as it was geared for the 454 and he had the top of the outdrive redone a few years ago. He also made me aware of something else. He said when you're out there doing around 40-45 and hit it, this engine should push you into your seat. He said this boat doesn't do that. It starts sputtering a bit. Apparently when the upper half of the engine was redone, you're supposed to run it then adjust the valves? That was never done and he thinks there may a compression issue as well. I'm putting it in the water on Memorial Day and I'll finally be able to run it myself, I'll let you know what's up."
 
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