Long shaft to short conversion

[npenson]

I have a 85 115hp inline 6 mercury that is a 25" lower and I want to make it a 20". I have taken the lower off and I see the spacer that can come out but does anyone know what items I would need to purchase to make the change? I have been using the motor on the boat as it is but I know it sits too low in the water and could be getting much better performance out of it raised up.

 

[GA_Boater]

Re: Long shaft to short conversion

This needs some pictures so we know exactly what you have to start with. I have some thoughts, but I need to see it.

 

[Chris1956]

Re: Long shaft to short conversion

Pictures would be nice. Normally you would need to remove the spacer, change the mounting studs to shorter ones, and install new driveshaft and shiftshaft. There are some driveshafts that have adaptors that lengthen them. Not sure about shiftshafts.

It would probably be easier to get a 20" gearcase and install it. Where are you located?

 

[npenson]

Re: Long shaft to short conversion

I can get some pictures later this week as I keep the boat at a friends house. I am in central VA. The drive shaft is a single piece without the adapter I do know that from when I had it apart last year.

The current gearcase I have works fine I was just thinking it would be cheaper to swap a few parts. I have seen a lot of used parts on ebay fairly cheap.

 

[npenson]

Re: Long shaft to short conversion

I still have to double check part#'s and what not but I think all I need is the following

water tube
exhaust tube
shift assy rod
drive shaft
and the 3 studs

You think I am missing anything? If this is all I need I think I can do it for well under 300. which I think it will be worth doing.

 

[wired247]

Re: Long shaft to short conversion

I have a friend that I work with that has a 80's 115 that the lower went out on. The shift linkage is just screwed up. He bought a new complete lower unit from some Indians for $250 (They have tons of that crap laying around ) . New as in new in box NOS new. Anyway he wants me to install it for him next week some time.I'll probably end up keeping the old parts. If you havent found anything in a few weeks let me know and you can have the driveshaft shaft and what not for free. The shift shaft can be easily shortened and repinned BTW.

 

[npenson]

Re: Long shaft to short conversion

I have a friend that I work with that has a 80's 115 that the lower went out on. The shift linkage is just screwed up. He bought a new complete lower unit from some Indians for $250 (They have tons of that crap laying around ) . New as in new in box NOS new. Anyway he wants me to install it for him next week some time.I'll probably end up keeping the old parts. If you havent found anything in a few weeks let me know and you can have the driveshaft shaft and what not for free. The shift shaft can be easily shortened and repinned BTW.

Thanks. Hardest part has been making sure part numbers are correct and I am getting all the parts I need. Is there anything I'm missing?

 

[GA_Boater]

Re: Long shaft to short conversion

Do you have the mid-section with a 5" extension? Or a 25" mid?

 

[npenson]

Re: Long shaft to short conversion

I have not put a tape on it but there is a spacer on the lower unit that is separate. It's been over a year since I have had it apart but was wanting to make this change before running it this year. I'm not even positive it's a 85 model to be honest as I couldn't find the numbers on it earlier today. It does have electronic ignition (no distributer) power tilt, no oil injection. And I am pretty sure the last parts I got for it where for 85.

 

[GA_Boater]

Re: Long shaft to short conversion

Picture?

 

[npenson]

Re: Long shaft to short conversion



This is not my lower unit but its very similar to it. Has the same spacer at the top

 

[npenson]

Re: Long shaft to short conversion



This is pretty much identical to mine except for the sticker covers