I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

Hello, so this weekend we took the boat out for the normal weekend run. we ran for a good 3 hours about 100 yards from the dock the lower unit got locked on my 1985 evinrude 115. so we take it home pull the lower unit out drain the oil everything looked fine but when we looked at where the shaft connected to the gears the shaft got so hot it twisted and broke off. I luckily have a 1993' johnson lower unit sitting in the shed so we install it oiled it up and we installed it. we had a tough time starting it because the motor wouldn't spin as fast as it normally would with the starter and when we actually get it started we get this whirring noise coming from the lower unit almost like a supercharger. the gear go in without even a click but we are concerned about the whirring any suggestions on what it could be?

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

Well

Are you sure that is a direct swap out item? The gearcase P/N does match but Im unsure of the guts inside.

Im showing the driver shaft P/N off the 1993 to be

5007671 for the 20" shaft
5007672 for the 25" shaft

And the drive shaft P/N off the 1985 to be

5000777 for the 20" shaft
5000778 for the 25" shaft

The motor not spinning as fast and the sound come from it as opposed to the original lower unit makes me belive...

1) Its not a direct replacment for the year, even though it looks the same in the schematic. Something is rubbing.
2) The 1993 Lower unit had it's own problem. You sure the 1993 unit was %100?

Im new to the Evinrude/Johnson world (Ive messed with Merc's though) so im still learning. Is the prop spinning, mabey its in gear slightly. I dunno Im just trying to think of what it could be.


DamianJP

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

I think the drive shaft is longer on the 93.

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

thanks for your reply the prop spins freely you barley touch it and it spins my father and i a trying to brainstorm we think it could be the pump installed backwards and when the impeller spins it wants to expand thus making it harder to spin but we still cant figure out the whirring i don't think it is slightly in gear because of how i stated before that if you barley poke it, and it spins

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

Well I think the only thing you can replace backwards is the impeller, and even so it should right it self. How is the 'pee' stream when it started?

Did you try to turn the shaft before you installed the 1993 lower unit? If so how did it feel? Again do you think the 1993 lower unit was %100 and had no previous problems?


DamianJP

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

the lower unit's shaft is really hard to turn it took my dad two ands and he is a big guy. the pee stream is good i think the lower unit is in good shape other than the shaft being hard when i try to turn it, when i goes in gear it does not even make a sound other than the whirring.

agustin

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

On my last lower unit, which wasn't the right model for my motor, the o-ring that goes right below the drive teeth didn't fit well with the shaft. It made whirring supercharger'esque noise as it rubbed. Through a lot of trial and error I discovered this was the cause. Eventually it wore through and disappeared and was never seen again and the problem was "solved".

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

Have you pulled the prop off to see if it has rolled up an entire fishing pole worth of line? That would make a whirring sound.

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

yes it has a new propeller

Re: I put a 93'115 johnson lower unit on a 85' 115 evinrude powerhead noise help?

ok so we found out that the shaft is about 1/8 of an inch longer on the '93 lower unit is it safe to sand the head of the shaft down bout 1/8 of an inch with no harm?