replace with sei

[joelogan]

I am thinking about replacing my upper drive with an sei unit and need some answers.
I have a Mercruiser 1988 4.3 alpha one that is bad. Do I need the 90-106 drive or the 90-104 (old style upper)?
Also does everything I need come with the drive? I read somewhere that I might need a new shift lever.
Is there a kit that has everything I need? I read that the gear ratio has been replaced from 1.84 to 1.81.
Mine is an 1.84R

Thanks
Joe Logan

 

[a1nowell]

Re: replace with sei

joelogan,
Contact SEI about the ratios and what comes with the upper unit. I replaced my upper Alpha 1 R with a SEI unit two years ago and it bolted right up, no problems. I do not remember if it came with a new shift lever, I don't think it did. But the people at SEI were a great help in confirming what I had, what I needed and installation guide lines.

 

[Bondo]

Re: replace with sei

I am thinking about replacing my upper drive with an sei unit and need some answers.
I have a Mercruiser 1988 4.3 alpha one that is bad. Do I need the 90-106 drive or the 90-104 (old style upper)?
Also does everything I need come with the drive? I read somewhere that I might need a new shift lever.
Is there a kit that has everything I need? I read that the gear ratio has been replaced from 1.84 to 1.81.
Mine is an 1.84R

Thanks
Joe Logan

Ayuh,... Welcome Aboard,...

If yer transom assembly is original 1988, it's an Alpha 1,...
Not the Gen.II... That's '91, 'n later...

'n the 0.03 difference in ratio is irrelevant...

What shift lever ya talkin' 'bout,..??

 

[achris]

Re: replace with sei

I am thinking about replacing my upper drive with an sei unit and need some answers.
I have a Mercruiser 1988 4.3 alpha one that is bad. Do I need the 90-106 drive or the 90-104 (old style upper)?
Also does everything I need come with the drive? I read somewhere that I might need a new shift lever.
Is there a kit that has everything I need? I read that the gear ratio has been replaced from 1.84 to 1.81.
Mine is an 1.84R

Thanks
Joe Logan

That ratio change was due to a gearset change in the lower gear housing. Merc changed the tooth count to reduce lower gear housing noise. It changed the overall ratio by a small amount. If you have an older lower and are just changing the upper, your gear ratio will remain the same.

 

[LilRedNeckGirl]

Re: replace with sei

I agree, Contact SDE directly, Have your info ready, Boat make, model, and the numbers off the old drive unit. They are awesome about hooking you up with the right parts. Right parts means everything lines up, installs properly, and gear ratios , drive direction, and connections are proper.
I had one installed last year with no issues....

 

[achris]

Re: replace with sei

I agree, Contact SDE directly, Have your info ready, Boat make, model, and the numbers off the old drive unit. They are awesome about hooking you up with the right parts. Right parts means everything lines up, installs properly, and gear ratios , drive direction, and connections are proper.
I had one installed last year with no issues....

Boat make and model is completely irrelevant. 1988 4.3 ran a 1.84:1 ratio. All they will need to know is that it's an Alpha One, and that ratio...

 

[LilRedNeckGirl]

Re: replace with sei

Boat make and model is completely irrelevant. 1988 4.3 ran a 1.84:1 ratio. All they will need to know is that it's an Alpha One, and that ratio...

may be non pertanant info, BUT, more info given is better then incomplete info. for us non mechanical people, that tend to pay someone else for their experties, i found, from years of driving cars and boats, that giving the most information in the beginning helps get the right parts the first time.
When I got my SDE drive, I gave them all the info I had on the boat, year make model, engine and drive numbers, engine size, etc. That also applies to the many other parts ive replaced during the normal curse of yearly maintainace. the right info can be sorted from a long list of identifyers by a compatent parts person or mechanic. What they cant do, is magicaly pull missing info from the air.
My SDE drive arrived a few days later and bolted in with no issues. right ratio, right everything.
so TMI is never a bad thing when dealing with replacment parts for boats.