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Need help on lower unit 20hp and 9.8hp

S

sgms18

New member
I have a 20hp merc that leaks gear oil when you leave it proped all the way up on the latch for a few days. It is a black and blue tiller motor that I rekon is mid 70's to early 80's though I don't know for sure cause there is no S.N.. I'm guessing it's the shift shat seal and wana know is there any other seals I should replace when I'm in there? I have never had a lower unit apart before so I don't really know what I'm getting in to. How difficuul a job is this, are parts and peices going to go every where whrn I pull the foot off?

Next we have a 1970 merc 110 9.8hp that I just rebuilt the carb and fuel pump on and it runs great! But....... now it's not peeing out the weep hole
mad.gif
So I guess I gota put an impeller in it. Same deal as above, what am I getting in to?
 
Tearing down a lower unit to reseal it is not for the faint of heart :)

It isn't rocket-science but you need a decent manual and a good tool assortment. The manual is a must because if you reinstall one thing upside down or backwards or out of order you can toast your gears.

There are lots of little rings, seals, o-rings etc on both the shift shaft and drive shaft (either of which could be leaking in this case).

And if you are going to reseal those you may as well do the bearing carrier as well because if you don't, it will start leaking next.

I can't find a listing for a "seal kit" (which many models have) but a quick check of active parts shows that just about anything you would need is still available.

As to your 9.8 (covered by the same manual by the way if you grab a Seloc's) - if you are contemplating taking on a lower unit reseal, an impeller change can be done with your eyes closed :)
 
Getting the LUs back on for those motors is a royal pain in the *ss! (Just did another one yesterday.) You may find that the drive shaft seal is also bad, and that the shaft is rusted there (making it leak even with a new seal).

On the motor that's not putting water out the Tell Tale, it might be plugged. Blow some compressed air up it and see.

Jeff
 
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