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Cautionary tale- Generator gear, coupling

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My new to me 108-3 had a few oil leaks and so I decided to replace some seals, notably the tach drive seal and also the generator gasket.  I spoke to Susan at Franklin Engine and she recommended that I also look at the rubber drive coupling.  So, since it was apart and it has about 600 SMOH I ordered the seal, gaskets and the coupling.  The old generator coupling came apart in 3 pieces, but it was all there.  Old age and hours had killed it.  I put in the new coupling but the drive gear was still loose.  I did not know what the gear was supposed to look like, but after looking at the way it was engineered it was apparent that either the gear was really worn from the old coupling being able to move around, or the "special washer" was worn, or both.  Susan was able to supply me with a used gear, in spec.  The new used gear had a small lip around the mounting hole that raised the mating surface to the washer up a slight amount.  So now my drive gear fits nice and snug.  

The caution here is that this drive should be checked if it has not been off in a long time.  I believe Susan said every 300 hours (or it has been a long time) it should be replaced.  It is not a big job and it could lead to a nasty surprise if not taken care of.  An added benefit is that getting to the tach drive is very easy with the generator off, and the seal is very easy to replace.  Now I just have to wait for my A and P to be available to put this back together.  



Posted : 16/04/2022 2:09 pm
Katherine, Bret, Katherine and 1 people reacted
Glen L'Heureux L'Heureux
Posts: 20
Eminent Member

Thanks for that, Kurt.

Good stuff.


-glen N168C

Posted : 17/04/2022 2:55 pm
Bret and Bret reacted