Mercury 115 crankshaft seal

[hermannm]

While winterizing my boat I noticed the spark plugs on the bottom two cylinders were rusty on the bottom of the plug (inside the motor). From what I have read this can be a crankshaft seal issue. Are there any other issues that could cause this?

We put oil in the cylinders and cranked it over a few times. Is there anything else that should be done?

Any videos or manuals to replace the crankshaft seal?

Thanks in advance.

 

[racerone]

If water is inside the motor it can lead to corrosion of bearings.------Water could be leaking in from bad gasket inside the exhaust cover.---Best to look this over and make 100% sure there is no water on bearings !

 

[Chris1956]

Water in the bottom cylinders can come from a bad crankshaft seal. It can also come from bad exhaust cover, exhaust baffle or gaskets, as Racerone said. Replacement of either requires that you pull the powerhead. Well, technically you can pull the exhaust cover, w/o pulling the powerhead, but it is real hard to do.

If it were me, I would replace the crankshaft seals (use 3 seals), and test it. If it still fails, you will need to investigate the exhaust cover.

 

[hermannm]

Thanks for the advice. Are there any manuals or videos on how to replace the crankshaft seals? I have tried searching youtube to no avail.

 

[Chris1956]

Sure, try an unexpected source......a service manual for your motor