Water in my gear oil

[JF660R]

We have a StarCraft with a '76 Merc 850 Thunderbolt, the SN is 4537364. Just got the boat this year and have had it out 4 or 5 times.

We immediately installed a new water pump kit. We are currently draining and refilling the lower unit oil before every trip. The oil comes out an off white color every time.

Looking for input on which seals we need to buy / replace. Part #s or sources would be really helpful. Wanting to make sure I order the right parts.

Thanks

 

[racerone]

Re: Water in my gear oil

Order a complete seal kit.---This site and other sites or your local friendly mercury dealer.

 

[TD_Maker]

Re: Water in my gear oil

Racerone is correct. At this point I would go ahead and replace all the seals on the Gearcase. Don't forget not to use the filler screw seals more than once. These little plastic crush washers have caused many leaking lower units. If you really need to know about an individual leaking seal, I would rig a pressure tester or vacume tester. They will tell the story.

 

[Chris1956]

Re: Water in my gear oil

The seal in the waterpump base is the prime suspect, in my experience. Drop the gearcase, remove waterpump cover, impeller and wearplate. Now sand the driveshaft to remove any rust, and lube it with oil. Pry up the waterpump base and replace it with a new one. Make sure you lube the seal in the pump base before installation. Now reinstall the wearplate, gaskets, impeller and pump cover.

 

[JF660R]

Re: Water in my gear oil

Thanks for the responses. I've been hunting the iBoats store but not seeing the 85 horse option. Looking like maybe the 70 horse kit would work, fits the serial # range anyway ??

I found a kit here that fits the power and SN range.
LOWER UNIT SEAL KIT

But a little pricier than the iBoats 70hp kit.
Lower Unit Seal Kit for Mercury, Mariner 26-85090A2, Chrysler Outboard, Force 26-85090A2, GLM 87808 - Sierra 18-2624

 

[racerone]

Re: Water in my gear oil

Look for the proper seal kit from sierra.---You might look for a kit for the 80 hp model.--18-2653 comes to mind.

 

[JF660R]

Re: Water in my gear oil

Look for the proper seal kit from sierra.---You might look for a kit for the 80 hp model.--18-2653 comes to mind.

That's what I'm seeing here too
Mercury & U.S. MARINER Outboard Gearcase Seal Kits -- Mastertech Marine
still no 85hp designation though, weird

 

[racerone]

Re: Water in my gear oil

8o hp or 85 hp is all the same lower unit.

 

[JF660R]

Re: Water in my gear oil

8o hp or 85 hp is all the same lower unit.

that's good to know, because iBoats has a good price
Seal Kit for Mercury, Mariner 26-55682A1, GLM 87520 - Sierra 18-2653