Water in gear oil-1977 Merc 850

[tallcanadian]

I was going to change my lower unit lube and I see that I have water in the oil. Could you great Merc gurus tell a fella where all the seals/gaskets are. I believe there is a rubber seal at the prop shaft? And probably around the Impeller?...Any help is appreciated.

 

[GA_Boater]

TC - There are one or two O-rings on the bottom water pump housing and one or two seals on the drive shaft under the housing too. One seal on on the shift shaft. And on the prop shaft, one seal and the prop shaft carrier has a large O-ring that seals the carrier to the lower unit case.

This is all from memory, so the quantities aren't exact.

 

[tallcanadian]

The motor was on the stand all winter and nothing leaked out. Can I assume that the seals by the prop are okay since they didn't leak?

 

[Chris1956]

You cannot assume the prop seals are good, but, it is likely, and it is easy to change the other seals and see. Buy a new waterpump base, as it will come with a new driveshaft seal, oring and base gasket. You will need new fill and drain plug seals as well. Drop the gearcase, and clean the driveshaft with sandpaper. Now lubricate the driveshaft and remove the slinger, upper pump cover, impeller, wearplate and gaskets. Now pry out the waterpump base with two screwdrivers. Be careful not to mar the gearcase mating surface. Now install the new base, gasket and oring. If the impeller is a year old or more, replace it as well. Do not turn the old impeller around. Reassemble the rest and install it to the motor. Now new gear lube if necessary and new gaskets on the fill and drain plugs. Tighten with a hand impact driver.

 

[Mi duckdown]

^ Very good advice.

 

[tallcanadian]

I appreciate the email. I certainly will get the parts this week. You make it sound easy anyway. I'm hoping that this bad boy will fire up today. I bought this motor about 16 months ago. The PO did run it for me. Compression is good on all 4. I'm not going on the water until this thing is running near perfect. I will probably have to take the carbs out and clean these. Thanks again for everyones input.