1975 25 hp Gear noise

[schwar74]

Greetings,

I just finished rebuilding my lower unit due to a worn clutch dog and fwd gear. I bought a new clutch dog, and then used a good salvage fwd gear from a gear set I bought. I reused the pinion gear and the reverse gear from my motor as they looked to be in better shape than the ones that I bought. After reassembly the gears made a sound like they weren't fitting precisely. It wasn't a grind and it turned all the way around many times without binding up. After installation and starting the motor, there is a whirring sound, like a car in reverse. It shifts normally. I idled it in fwd and rev. without an issue.

My question is: Do the gears need to wear in? After time, do they mate up better? Do I just need to run it?

Thanks,

Scott

 

[dew2]

Re: 1975 25 hp Gear noise

Did you get the washer/spacer back in on the pinion?

 

[schwar74]

Re: 1975 25 hp Gear noise

Dew, Good question. I was paying too close of attention to the thrust bearings on the fwd/rev gears. I'll check my bench to see if there is one laying around. Is this a likely culprit?

If I do have to go back in, can I use the same spaghetti seal on the case? I used a new one when I reasealed this one.

Thanks.

Scott

 

[dew2]

Re: 1975 25 hp Gear noise

You mentioned it sounds as though the gears dont mesh,The pinion it the only one that needs the washer/spacer to set its height,the others are set with their bushings, I have done those lowers and dropped the washer out and thought where does this go? Had to go to a schematic to see what it was.One I droped and never knew it was gone,found it accidently 1/2 way through install,never knew it was gone. Thats the reason I ask
I'd use the same spehgetti its not old and compressed yet, you did use 3M 845 sealer right?

 

[schwar74]

Re: 1975 25 hp Gear noise

Dew, I'm assuming you put the washer/bushing back in before you finished the reassembly.
I read on another thread regarding a similar situation, a replaced pinion gear, that someone mentioned to "take it easy for 5-10 hours" after the rebuild. I'm assuming this means that a break in period is needed to allow the gears to mate up. Does this make sense? I don't want to ruin the $250 worth of parts I put in, but I'd rather avoid another disassembly if possible.

Thanks,

Scott

 

[dew2]

Re: 1975 25 hp Gear noise

Never heard of that,Gears are machined to mesh.Now a new engine needs a breakin period.
Was the washer/spacer in under the pinion?
Question from me??? when you disassembled the gears did the forward and reverse both have thrust washers? I dont know if you follow other threads here but it is one on here.I took two lowers apart and only the reverse had a thrust washer. How about yours.Mine are 1975 also.