Should oil deposits be in the powerhead

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wtcarter4

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Recently acquired a 1981 Johnson 15hp and replaced the water pump/impeller due to weak stream coming from the tell-tale. After replacing with a new pump/impeller, it still had a weak flow. I ended up pulling the power head from the case. I removed the plate that contained the inlet and outlet lines that bring water into the power head, for it to be pushed out. First thing I noticed was a rubber grommet that was broken up and wedged into the opening of the water inlet line. (Culprit of the weak stream I hope?) What concerned me, is that there is a lot of oil deposit inside of the area that goes up into the power head. I would assume that should be pretty clean, as water should be the only thing cycling through the power head to cool it down? Am I right assuming that? IF that is so, I assume the seal around my crank shaft is faulty and would need replacing. (There was a little bit of oil build up between the plate of the water pump and the foot where the shaft enters, however I did not notice any on the inside of the pump or impeller.) I know this is long winded and hope someone can understand what I’m trying to say and could offer some input. Thanks!
 
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racerone

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Lubrication on a 2 stroke is not well understood.----You mix oil with the gas.----Some of this oil and gas goes right through the motor and is wasted.-----Shows up in the exhaust housing and alarms a lot of people.
 
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wtcarter4

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I realized that last night as I done more reading and researching. It just baffled me that there would be somewhat excessive oil deposit in the exhaust system. I would have thought most of it would burn off and there would be carbon buildup. I’m no mechanic, so I don’t understand every detail on how an engine operates. I’d assume that means it has been running rich?Thanks for the reply, definitely helped ease my mind.
 
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racerone

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Not at all.-----A 2 stroke wastes gas and oil !!----A new motor in 1981 wasted this gas and oil the same way that same motor wastes it today.-----I have said it many times " 2 stroke operation and lubrication is not well understood " .----And 50 years ago folks were confused by it and it appears even more so today.
 
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Crosbyman

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wtcarter4 said:
I realized that last night as I done more reading and researching. It just baffled me that there would be somewhat excessive oil deposit in the exhaust system. I would have thought most of it would burn off and there would be carbon buildup. I’m no mechanic, so I don’t understand every detail on how an engine operates. I’d assume that means it has been running rich?Thanks for the reply, definitely helped ease my mind.
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when a new load of fuel enters the cyl. on the downstroke.. that fuel entering the cyl pushes the burnt fuel oil mix out the exhaust ports. unfortunately the ports being opned during that time will also permit a % of freah fresh fuel oil mix to take the same way out the exhaust... hence the wasted... now even more expensive fuel oil which ends up in the water or drips slowly down the inside of the exhaust channel to the prop.

modern direct injection motors don't do that and save a lot of waisted fuel oil ...my 75 ETEC burns .6 l (2 wine glasses ) per hour trolling !
 
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wtcarter4

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Crosbyman said:
when a new load of fuel enters the cyl. on the downstroke.. that fuel entering the cyl pushes the burnt fuel oil mix out the exhaust ports. unfortunately the ports being opned during that time will also permit a % of freah fresh fuel oil mix to take the same way out the exhaust... hence the wasted... now even more expensive fuel oil which ends up in the water or drips slowly down the inside of the exhaust channel to the prop.

modern direct injection motors don't do that and save a lot of waisted fuel oil ...my 75 ETEC burns .6 l (2 wine glasses ) per hour trolling !
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Awesome information! I’ve had 2 stroke dirt bikes in the past and never had any issues with them, so I never had the need to work on them. I didn’t think about the fact that if you add water in the mix with a 2 stroke that’s pushing exhaust back out of the foot/prop, I see where there could be buildup of unburnt oil/gas because of the obvious moisture causing it to essentially “clump” up. This is my first 2 stroke outboard, so I have a lot to learn. My plan is to take my time to reassemble and inspect the parts to get a better understanding.
 
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