[treeclimber]

Hi, I have a 1962 9.8 Hp mercury 110 lightning (SN 1546962) that has a 6 spline propeller shaft and I need to upgrade to a 8 spline propeller shaft, because the 6 spline hub inserts for the propeller are no longer available. Has any one had this problem and how can I get past this nightmare? It has 120 lbs. of compression in both cylinders and runs great... I would hate to see a good motor put in the junk pile. Do I have any options? Thanks, Ron.

[Laddies]

It will require more parts than a shaft your best bet will be to find a later engine with a good lower unit as a doner

[treeclimber]

Thanks for the info, I would swap lower unit parts from an 8 spline housing but i just don’t know what model years are compatible with my lower unit housing. I would like to go with a newer year if possible but not necessary just as long as the internal parts fit. Shopping on eBay is risky so I need to know exactly what I’m looking for.
Thanks again, Ron.

[Harker]

I think they changed from 6 to 8 spline in 69 or 70. I'm not sure about the driveshaft splines though. Sometimes you can find a 6 spline prop on ebay that is in good cond.

[Laddies]

Here is a parts list for the 110 engines maybe it will help to get the part numbers. http://www.mercruiserparts.com/selec...sp?doc_nbr=110

[treeclimber]

Hi, every one thanks for all the info... it has been a great help. I believe i have found a good 1978 lower unit with an 8 spline shaft, I will see if I can get it for a fare price and use the parts in mine. I will keep you all posted on my progress, I once again have hope for this great old motor. I thank you and I wish you all a Merry Christmas, Ron.

[treeclimber]

Hi, it is Christmas day and I'm as happy a kid in a candy store...in my case it's a toy store. I won the lower unit on eBay for $104.29 Shipping and insurance included. Seller has a good reputation and he answered all my emails... motor has locked up due to a bad water pump, it has no oil leaks or rust/corrosion and the propeller is in great shape. I have my hopes up but it still could be a dead end if the parts don’t swap over. right now I must wait for it to arrive before I will know for sure; If it don’t work I still have my old dependable 1972 6 Hp Johnson that I can putt around in, to me its not all about the size of the motor or how fast I get there; just being able to go fishing is what matters to me. I forgot to mention that my boat is a 14' aluminum flat bottom. I will be back to give every one an update around the first of the new-year. Ron.

[treeclimber]

Hi, everyone I have good news the 1978 lower unit swapped out; the 1978 unit was not in as good shape as first thought; it had bad seals and some water in it but no corrosion. I had to use the gears and prop shaft of the 1978 unit... I test ran it in a 55 gallon drum and found the water pump and shift seals to be leaking but not too bad, I just don't want to pollute the lake. I have to order the seals and wait for a warm day to take the boat for a test run. This is another good example why we shouldn't give up to soon..."where there is a will there is a way". Thanks again to all who have replied to my post.
Sincerely, Ron.