1.81 Alpha drive with 120 4 cyl merc ?

[pugsley]

Bought a "fixer upper" with a 1987 120 Hp engine. Removed the Od to service and found that it is a 1.81 upper drive. Stamped D on casing and drive shaft. Serial A531502 Inspected and counted upper gears and sure enough had 17 and 19. Merc manual identifies it as such. I know that it should be a 1.98 upper for this engine. Should I use the 1.81 and what kind of performance problems will I have. The boat is a 1987 18 ft Galaxy in fair condition but really don't want to buy an upper or another drive if I can use this one.:facepalm: Thanks

 

[Bondo]

Re: 1.81 Alpha drive with 120 4 cyl merc ?

Ayuh,... What's the Prop,..??

It might work with a 15",... maybe...

 

[pugsley]

Re: 1.81 Alpha drive with 120 4 cyl merc ?

It has a 14 x19 michigan prop. I was wonderingif I could getaround this by playing with props, but confess that this is beyond my level. Checked the manual again and appently it is a 1.84.So if I understand this right my main problems are going to be too many rpms? Or am I bassackwards? Thanks

 

[Bondo]

Re: 1.81 Alpha drive with 120 4 cyl merc ?

Or am I bassackwards?

Yes...

 

[pugsley]

Re: 1.81 Alpha drive with 120 4 cyl merc ?

Ha ha.I guess I should have got the trusty calculator out. Even at 1.84 it makes a hell of a difference doesn't it? Duh..Damn, I really thought I looked his thing over pretty good. Bought a dozen or so boats and never saw this but after all, ebay means buyer beware. Somebody obviously switched outdrives. Guess I'll break out the checkbook. Thanks Bondo, you just saved me a bellows kit + and a whole lot of aggravation.