Lower Unit

[ndfool]

Can someone tell me if a late 70s early 80s merc 65hp lower unit would work with a 1979 merc 80hp, 4cyl.?

Thank You

 

[Laddies]

Re: Lower Unit

Yep, as long as they are both 4 cyl

 

[ndfool]

Re: Lower Unit

Thanks!

 

[ndfool]

Re: Lower Unit

Another question
Sorry for being a bother, I am new at this and don't want to get a part that will not work!

Will a 1972? 80hp lower unit fit a 79

The serial number on the 72 is 3145923
Part# on lower unit casting is 1623 605

Thank you

 

[ndfool]

Re: Lower Unit

Anyone?

 

[Laddies]

Re: Lower Unit

All the mid sized gear cases for 4 and I/line 6 engines will bolt up but there are straight cut and helical cut gears and differant gear ratios plus a few that are short shaft.

 

[ndfool]

Re: Lower Unit

How does one figure out what years, models and such will work?

Based on the prices for lower units on the web, I am not going to be able to afford any of them, with the exception of Ebay. But the Ebay lower units don't always give me enough info and the people selling them don't always know.

 

[WillyBWright]

Re: Lower Unit

Heck, the mechanics working on them don't always know. 800s and 850s used different gear ratios, depending on the year. I ran into that rebuilding two to go on a houseboat. But you can usually compensate with prop pitch. The gearcases of the inline-4s (from 65Hp) and inline-6s (to 150) all fit eachother in that timeframe. The next big change came with the inline-4 100s in the late 80s. Very roughly, most anything from the mid 60s to mid 80s will fit. You can add a few years plus or minus depending on the model.

BUT...I'll bet the gearcase you're considering is from a 3-cylinder. Only 3-cylinder models from 50-70Hp of that era will interchange. The gearcases of the 4's and 6's are larger.

 

[ndfool]

Re: Lower Unit

No, mine is a 4cyl, see the start of this thread.

Thank you
I am sloooowllly learning

 

[WillyBWright]

Re: Lower Unit

650s were triples starting 1972. So a gearcase from any 65 made from 1972 wouldn't fit your 80. Just up thru 1971.