Heavy grease in jet unit exhaust tube

[shadowrider]

I have a Mercury outboard jet (1973 85hp) , the exhaust tube was dripping thick liquid. I looked in the exhaust tube and the entire pipe has a 1/4" deep
puddle of grease in it. What the heck is this? I want to say it is bearing grease from the bearing. Could the seals have inverted and dumped into exhaust tube?

 

[shadowrider]

Re: Heavy grease in jet unit exhaust tube

I guess yall are stunmped too ?

 

[Lone Duck]

Re: Heavy grease in jet unit exhaust tube

Well yes it could be bearing grease. Or it could be unburned mix oil. How does it run? Are the plugs black and oily ? Do you mix 50:1 ? What does the drive shaft look like ? Is the impeller housing coated also ? Is there a lot of grease between impeller housing and drive shaft bearing ? Is it excess gasket goo ? send a pic.

 

[shadowrider]

Re: Heavy grease in jet unit exhaust tube

Engine runs great, I use 50;1 oil, I have not pulled apart since changing impeller. At that time, seemed to be excessive grease from bearing under impeller. I think fella I got it from used a regular grease gun. I regreased with low pressure tube. No pics right now.Thanks for reply.

 

[Lone Duck]

Re: Heavy grease in jet unit exhaust tube

Yep! It sounds like grease from bearing. My jet foot is for an 82 90 hp merc. The foot has a rubber tube on the side which connects to the bearing grease zerk. When greasing,I connect my gun to the zerk and watch while I'm pumping for water to come out of the tube. I pump until all the water is out and clean grease comes out. Then I hook the tube back on the grease zerk It has a fitting the same as the fitting on a grease gun. Is yours the same ? If it is make sure the tube is not plugged. Or it will over pressure the bearing. I saw one once that the guy took the tube off and plugged the fitting. all the grease and water caked the bottom of the impeller housing and he blew the bearing. I gently grease mine every time I take the boat out of the water .

 

[shadowrider]

Re: Heavy grease in jet unit exhaust tube

My jet unit is evidently older, as it is not the same. It Has a zerk and a screw for the overflow side. Sounds like I need to replace seals ?

 

[Lone Duck]

Re: Heavy grease in jet unit exhaust tube

Yep! while you are in there do the bearing and the seal. In some jet foots bearing and seal are 1 unit. Have fun.

 

[shadowrider]

Re: Heavy grease in jet unit exhaust tube

Pulled jet pump, no sign of excessive grease. I determined that it was 2 cycle oil from an improperly timed engine. Fixed timing issue and I am confident this will clear up the residue.

 

[Lone Duck]

Re: Heavy grease in jet unit exhaust tube

Thanks for letting us know.