Alpha One Gen 2 outdrive

[dlogvine]

I just bought a boat with V6 mercruiser engine and Alpha one Gen 2 outdrive. It has a sticker SE116 on it (picture attached). I want to replace my current outdrive, also Alpha One, Gen 2 with the one i just bought. The engine on my old boat is Mercruiser 5.0LX V8. The question is, are these outdrives the same or they have different gear ratio and not compatible, the outdrive on my old boat just has Alpha One sticker, no SE116.
Also are the gimbals the same or different for these outdrives?

 

[thumpar]

The SEI drive is a direct replacement but it will not have the correct ration because of the different engines.

 

[Bondo]

Ayuh,.... As thumper says, the SEI is an aftermarket direct replacement drive,......

The 5.0l uses a 1.50:1 ratio, unless it's in a huge barge, then it could be a 1.65:1,.....

The 4.3l usually uses the 1.65:1 ratio, unless in a huge barge, when a 1.84:1 might be used,.....

 

[dlogvine]

No Title

Ayuh,.... As thumper says, the SEI is an aftermarket direct replacement drive,......

The 5.0l uses a 1.50:1 ratio, unless it's in a huge barge, then it could be a 1.65:1,.....

The 4.3l usually uses the 1.65:1 ratio, unless in a huge barge, when a 1.84:1 might be used,.....

How can I check what is the gear ratio on each of these outdrives? Also I only need to replace the lower unit housing on my Larson boat, it has a chipped piece from the broken fin. How hard would be to switch all the gear from one lower unit to another?

 

[dlogvine]

[FONT=Arial, Helvetica, sans-serif]THis is the chart I found for the gear ratios for Alpha One Gen II
[/FONT]

[FONT=Times New Roman,Georgia,Times]Horsepower[/FONT]​	[FONT=Times New Roman,Georgia,Times]Engine[/FONT]​	[FONT=Times New Roman,Georgia,Times]Year[/FONT]​	[FONT=Times New Roman,Georgia,Times]Ratio[/FONT]​
120 & 140	4 cylinder	1991 thru present	1.93 / 20-24
175 & 4.3	V-6	1991 thru present	1.81 / 17-19
198	V-8	1991 thru present	1.62 / 24-24
198 thru 260		1991 thru present	1.47 / 20-22

 

[Bondo]

Ayuh,.... You can change Just the lower unit, 'n the gear ratio don't change, as the ratio is determined by the upper unit,....

 

[dlogvine]

Ayuh,.... You can change Just the lower unit, 'n the gear ratio don't change, as the ratio is determined by the upper unit,....

Thank you!!! This is great news - much easier than I expected. I was going to change impellers on both drives so it will be an easy switch.

 

[Rick Stephens]

That cavitation plate is pretty fixable.

Also, the 1.84 upper could still be used with the 5.0L, you would have to prop up a bit. The props you own for the 1.64 gear ratio drive would not be turning as fast with the 1.84 SEI upper. Only about a 8% difference between the two, so not a big deal to match up a prop.

 

[dlogvine]

That cavitation plate is pretty fixable.

I'm can try to weld the cavitation plate, not sure how to go around the trim tab or anode.

 

[Rick Stephens]

Use a router with an end mill in it. Thin out the anode area. Doesn't have to be perfect to work perfectly.

 

[dlogvine]

what kind of aluminum should i use? would any aluminum bar of the right size work? and after i weld it on, should I use POR15 paint or any automotive paint would be fine?

 

[Bt Doctur]

You get a donor broken lower ,cut the section you need, section it to your lower .you use either aluma-weld or heli-arc

 

[Rick Stephens]

That's a good idea from Bt Doc. Get a lower off eBay or whatever that has spun a bearing, or an empty case without gears. See them all the time. I'd MIG weld that in a second. Don't even have to pull the internals since nothing really close to that part of the casing. Heliarc is good too - more heat since it is slower.

Paint doesn't matter. Should use zinc chromate primer underneath, but most any good quality black paint over that is fine.

 

[Bondo]

Use a router with an end mill in it. Thin out the anode area. Doesn't have to be perfect to work perfectly.

Ayuh,..... I agree,... Just grind, cut, fit any ole hunk of aluminum from the scrap heap that's close, 'n Go for it,......

The alloy won't matter, 'bout any scrap of 1/4" plate could be fit, 'n welded in,.....

Rustoleum zinc oxide primer on the bare metal, maybe another coat of red oxide primer, 'n shoot it with black industrial enamel,......

'bout any tools used on wood, can be used on aluminum,....
Waxin' the tool, alot, helps stop metal build up on the cuttin' edges,....
I use beeswax, as I've got a pile of it from an apiary,...

I'd mig it, as I've got one all set up in the garage,.....