Pain in the FOOT 6cyl merc

[JosephACavin]

I have a 1350 merc that I just got from a friend who said that it has a problem with loosing gear oil. He says it runs great for about 20 minutes and then it sputters and doesn't want to run.

When he checks the lube it is watered down and white. I am hoping that he has not messed up any gears and that it might just be the seals. Anyone have any ideas?

The problem here is I have not been able to work for four years now so money is a real problem. I would like to try to fix this myself for as little as possible but with long lasting results.

Thanks to anyone who can give me some helpful advice.

 

[diaric]

Re: Pain in the FOOT 6cyl merc

the quitting could be a few things. probably a fuel issue to sputter down. most likely cause would be a plugged up fuel vent. could be a bad hose, poor hose connections or worn fuel pump. water in gearlube would be from waterpump seals, fill screw seals and/or prop shaft seals. u don't say what years it is. the old motors corrode on the shafts and seals don't work properly. best way to narrow down is to pressure test lower unit. a manual is invaluable to rip this all apart, but most of it is fairly simple.

 

[Chris1956]

Re: Pain in the FOOT 6cyl merc

Joe, Tearing down the LU is a real PIA. The good news is that the propshaft seals are usually pretty reliable. The waterpump has a seal in it, as well as an O-ring and some gaskets that leak more often. I would start there. If you replace the waterpump base, it will come with a new driveshaft seal, for about the same price as the seal itself. Check the area of the driveshaft where the seal rides, especially if the driveshaft shows signs of rust. Clean it up with fine emery or crocus cloth. Make sure you install the correct oring on the pump base. Use the thickest O-ring that will fit and grease everything.

 

[JosephACavin]

Re: Pain in the FOOT 6cyl merc

The engine is a 1970 1350 6 cyl 135 HP with ThunderBolt Ignition.

I cranked the engine today and it was pretty noisey but I had the covers off, sounded like a Hugo that is getting ready to throw a rod but I have been told that is about normal.

I used the section cup thing with a hose pipe but only let it run about 15 seconds.

This motor had a water pump put in it a few years ago or so I was told, would it go out that quick?

Yeah I would really like to get hold of a manual.

Thanks for the info guys

 

[studlymandingo]

Re: Pain in the FOOT 6cyl merc

I replace my water pump annually as you never really know exactly how long the impeller is going to hold up. When someone else tells you the pump was replaced, they may mean only the impeller was replaced as you can buy a kit or the impeller alone. The difference in price between the two is usually less than $5.​