Question about oil in splash well from 1982 40 hp mercury outboard

[motor boater]

I have a 1982 40 hp "2 stroke" Mercury outboard that I purchased a few months back. I changed the impeller and gear oil as well as the starter brushes due to a bad brush. I just put it in the water last week and it started and ran fine.

After pulling the boat back out of the water and onto the trailer, I noticed some oil in my splash well area. I didn't bother to check if it was mixed with burned fuel, because I just didn't want oil on my newly painted boat. so I flushed it with water and wiped it clean with a rag. It seemed sort of concentrated though so I'm not sure if it was mixed or not.

is this normal?

the boat sits kind of low on the back end and at higher speeds water does splash into the splash well a bit.


also while using it on the water, there was a little bit of white/light colored smoke that I could see sitting on top of the water from my outboard. this is just due to the gas/oil mix right?

another question is, where exactly is the gas/oil supposed to come out of after its burned?. I used a 50:1 ratio and I filled the 6 gallon tank with 5 gallons of mid grade fuel (not 87 basic unleaded, but not the highest one either 91) don't know if that makes any difference.

please help.

 

[jjacobs007]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

motor boater! sounds like to me you have a fine running 2 stroke.
white smoke and grease film in the rear is common.maybe a leaking fuel line somewhere ect!!

 

[motor boater]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

What would make you guess it could be a fuel line possibly?. I will check it out

 

[mr 88]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

When you raise your motor the gas that is sitting in the carbs dumps out the overflow into the front cowling which leaks out into your splash well. To confirm take your cowling off before you raise motor and observe. 50-1 is the new normal with todays oil. The unburnt fuel/oil is sent out the exhaust into the lake and that is why you see the residue.I would run 91 octane with the cruddy gas they sell now.The difference for 6 gallons is what, 1.20$ ? and your combustion chamber may end up cleaner.The inline 6s retard there timing a couple degrees because of new fuel,don't think you have to do that,but nice to have a idea why.

 

[motor boater]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

Wow, that makes a lot of sense. I never saw the oil in the splash well until after I pulled the boat out of the water having the motor raised. Thanks mr88.

Now by retarding the timing, im assuming you mean slow it down a bit?

Also, im runing 89 in it right now (mid grade) should I just stick with that, or do you think I should really go to 91? And how would I go about finding out if I need to retard the timing?

 

[mr 88]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

The timing may not have to be retarded,I noted it was done on 6 cylinders and I am not sure if it makes any difference with a smaller displacement engine.Probably have to use the search icon or start a new thread on that.It is your call on the octane,I gave you may opinion and others will have there's as well.Don't want gas in the splash well ? Pull fuel line at engine and run dry when getting ready to load boat on trailer.

 

[motor boater]

Re: Question about oil in splash well from 1982 40 hp mercury outboard

Ahhh, good point. Should've thought about runing dry before load out.. Thanks.