TOPIC: Brand New/Old Merc 1000

I just purchased a 1961 Crestliner Explorer with a '62-63' Merc 1000 on it. I got the motor running on Saturday but it puking oil from the shift rod on the lower unit. When I changed the lower unit oil it had water that had separated out in it. Should I change all the seals or just the ones that appear to be leaking? I am a novice mechanic who isn't afraid to get his hands dirty. How hard can this be if I get parts from a local marine store or should I spend the $$$$ in labor to have the work done.

Just taking it to someone is easier said then done. A lot of people won't work on the old mercs. I'm sure with some help from the more experienced guys here you can do it.

There is a local shop that will work on Merc's. They have been very helpful and even stock the parts I need. Labor was a little pricey for the water pump replacement I had done right after I bought it. Parts are not bad, labor is the killer. Just don't want to get in over my head with tearing apart a lower unit before I even get the boat wet this year.

On a scale of 1-10 what is the difficulty for replacing oil seal, o-ring and bushing as long as the shift shaft is in good shape?

The job is not particularly difficult if you have the special tools to take the lower unit apart and the manual as a guide. The tools to strip the lower are available for a few hundred and the Merc manual will cost about $80 or so. Money well spent. Difficulty is about a 7 for the first time novice.

Here's the update. Replaced the shift rod bushing and oil seal, oil seal & o-ring on the water pump base and the water pump body, replaced the water pump gaskets but will probably need to be replaced again as they have been on and off now twice.

Pressure tested with 15 psi and it only lasted 2.5 hours. When I ran the engine it seemed to run real rich and had ALOT of extra oil and gas in the test tank and it was still puking gear oil and exhaust out of the same hole as shown above resulting in a geal oil slick. The water had a really strong gas smell.

As a side note I am now a pro at taking the lower unit on and off the motor.

Any thoughts on what to try next. The motor starts right up and all the wiring is in good shape. I really want to get this beauty running right.

Refresher. Early 1962 Merc 1000 with a sick lower unit.

In the manual it states that you can overshim the water pump base so there won't be any free play between the gear housing and the water pump base.

I purchased a shim kit from marinengine.com and added some shims to see if that fixes the leak.

I believe that my lower unit leak is coming from between the base of the water pump and the gear housing case.

Any thoughts or ideas? I could really use some advice...

Could it be the seals in the pump housing? If they are worn, I suspect (and someone else may be able to verify) that water would get into the gear case through the lower seal. Mine were worn and I found them easy to replace. Though it didn't solve my issue completely it noticeably reduced the amount of water in the gear oil. I have another leak that's not likely worth the effort to resolve as my gear case was cracked/poorly repaired and I think it leaks around the prop shaft.

I replaced the water pump oil seals. I will need to run it now the ice is off the lakes to see how it does.

Another forum said that if the drive shaft had rust on it would leak again regardless of new seals.

Yes, if the prop shaft is rusted/pitted/worn away at the location of seals then it wont ever seal completely. How much it leaks will depend of course on the amount of wear. There are solutions to this (something called 'speedy sleeves' I think, or finding one of the later model stainless shafts) but I don't know much about it....

also check the shift shaft seal. common problem overlooked

Ordered some speedi sleeves to fix the problem. it was a rusty drive shaft where the oil seals have worn on the drive shaft.