Merc Outboard Sport Jet 80 Outboard

[KennebecRiverGuide]

I am looking for a source for a rebuilt (or new) driveshaft with bearing and seal assembly for a 1998 Mercury Sport Jet 80 Outboard (115 Hp 4 cylinder powerhead).<br /><br />The pump is an Outboard Jet model "AC", Serial Number 63.100..<br /><br />My current bearing assembly seems to be fairly tight but I am starting to get some discoloration in the grease (turning greyish) indicative of water penetrating the seals.<br /><br />I don't want to take my engine down for some unknown period of time while I send the shaft out to be rebuit by a shop (bearing must be torched off), so would like to get my hands on a prebuilt shaft/bearing assembly to install myself. Would consider buying a whole pump assembly with shaft if in good condition (also looking for a nylon sleeve, Shear key, thrust cone insert and shoe/grate as spares).<br /><br />Clam's can you rebuild this shaft for me? I live outside of Augusta.<br /><br />Thanks in advance for any suggestions.

 

[dajohnson53]

Re: Merc Outboard Sport Jet 80 Outboard

Just to make sure we understand, this is an outboard motor a jet lower unit made by Outboard Jet company in the place of a prop lower unit? The jet lower unit is factory installed? It's not an inboard type Merc. Sportjet which uses a Merc outboard type powerhead, but adapted to be installed like an inboard motor.<br /><br />If this is the case, I believe the powerhead and leg are same as a 115 (relabeled 80 HP to reflect actual HP at jet outlet). The Outboard Jet unit pretty much just replaces the prop lower unit, and any parts (including driveshaft) are the same as would be used in a normal propped 115 of that era. You might check shop manual/parts list to be sure. The Outboard Jet lower units that I'm familiar with all simply replace the prop lower unit, no other major parts are different. Hopefully someone will chime in if I'm wrong, but you might check that out.<br /><br />Thanks

 

[KennebecRiverGuide]

Re: Merc Outboard Sport Jet 80 Outboard

YEs. This is a SportJet Outboard, not a Inboard<br />Sport Jet which is a OB Powerhead grafted to a <br />jetpump unit (ala Basstrackers).<br /><br />Thanks for the info. The shop manual seemed to indicate it was a special deal. I will have to go back and check the instructions regarding the shaft bearing for the normal lower unit.

 

[rodbolt]

Re: Merc Outboard Sport Jet 80 Outboard

that jet,if its not a saltwater issue, is simple to rebuild yourself. the drive shaft is NOT the same as the prop style shaft. been modified at the bottom. there are 2 seals and 2 bearings in a housing. I use a tourch and just melt the bushing off the shaft and the impeller will fall off. the wear ring and impeller have to have the clearence checked on reassembly. check the exhaust"muffler" for deterioration where it enters the pump. you wont believe how many techs have been wiped out by a bad 20 dollar tube. replace the seawater pump for the engine while its apart. the bearing any machine shop can press on and off.

 

[dajohnson53]

Re: Merc Outboard Sport Jet 80 Outboard

Rodbolt's post made me realize I had a major brain fart - yes indeed the Outboard Jet unit I have has it's own drive shaft. It's the same (as far as I can tell!) at the powerhead end, but not at the l/u end. When the prop lower unit is taken off (which I also have), it takes its drive shaft with it, to be replaced with the drive shaf that is part of the Outboard Jet unit. I'm sorry for giving bad information. I don't know what I was thinking - I've handled both of these lower units (prop and jet) so many times and that shaft is sitting out there - duh!!

 

[KennebecRiverGuide]

Re: Merc Outboard Sport Jet 80 Outboard

Ah.. thanks Rodbolt and D.. No problem pulling the impeller(got to hone it a couple times a year up here on the Kennebec - pebbly bottom where not<br />solid granite) and I have disassembled it a couple times to where I have had the driveshaft in hand during water pump impeller replacements. The manual indicated it was a factory type job to get the bearing off/on because of a requirement for torch heating the shaft and risk of warpage. I will check with my machine shop (also does my aluminum welding) when I tear down to replace my wear ring this spring. Thanks for the tip on the exhaust tube,I'll be watching for that.