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SUGGESTIONS PLEASE diagnosing blue smoke problem

D

dbmnj

New member
My 1994 Mercury 115hp 4 cylind

My 1994 Mercury 115hp 4 cylinder (with an oil injection system) is spewing large amounts of lite blue smoke.
1. I purchased a compression tester and found good results:
132psi top cylinder
132psi 2nd cylinder
140psi 3rd cylinder
140psi bottom cylinder

2. I purchased a SELOK repair manual but it doesn't provide any troubleshooting advice for this problem. The manual describes the oil injection system - but I am a bit confused about the Air Compressor and Check valve in the oil return hose - how do these contribute to the operation of the system? Could a faulty Check Valve be the cause of my problem?


3. I don't know what to do next. PLEASE PROVIDE SUGGESTIONS.
 
""does it smoke excessivel

""does it smoke excessively on start up and then run fine? more info needed"

Smokes almost all the time, and a lot! It started late last season, but I haven't put it in the water yet because I want to fix this problem on dry land."
 
"Could be running very very ri

"Could be running very very rich - just a wild guess here, but try disconnecting (and plugging) the feed for the enricher system.

The enricher is just a solenoid that is supposed to open when you push in the key to "gravity feed" extra fuel to the carbs for a cold start.

If the solenoid is toasted it may be "locked" open, giving you excess fuel/oil all the time - the equivalent of always running with full choke.

That's my thought for the day - now my head hurts
"
 
"Found this, probably doesn&#3

"Found this, probably doesn't help

Another common problem with the Mercury oiling system is a failure of a special crankcase pressure regulator and check valve. The Mercury oiling system uses crankcase pressure to lift the oil from the reservoir tank to the under-cowling tank. Positive crankcase pressure accumulates in the reservoir tank and forces oil to the engine. When the engine is shut off, this pressure is supposed to bleed down and stop the flow of oil. If the specialized crankcase regulator and check valve is malfunctioning, the pressure will not be bled off. This will cause oil to continue to flow from the reservoir tank to the engine. As a result of this pressure, excess oil will be pre-mixed with the fuel. On the next engine start the engine will have a very rich oil mixture, causing a lot of smoke. It can also cause hard starting

and
http://forums.iboats.com/Mercury-Outboards/Smoke

"
 
i think i would try running it

i think i would try running it on some pre mix fuel 50:1 and see wot the smoke is like then with the oiler disconected may take a few mins to burn any residue away. ps im a diesle truck man so im bound to be wrong
 
"The valve JB refers to has be

"The valve JB refers to has been changed in recent years because of the problem he stated. It was redesigned so that it would be more reliable at allowing the pressure to bleed down.

It is easy to test the valve. Run the engine for a few minutes, and after shutting it off wait a minute and see it there is any pressure in the hose from the crankcase to the remote oil tank.

Another possibility is that the link from the throttle linkage to the oil pump is not adjusted properly, or is not connected. If this becomes disconnected the pump will deliver maximum oil at all times.

Tony"
 
"Thanks for all of your help!

"Thanks for all of your help! The engine is running fine now due one of two changes that I made. I don't know which solved the problem.

1. I replaced the 2psi check valve that sits beween the oil pump and the fuel pump.

2. I adjusted the oil pump linkage according to the description in my original "outboard engine installation manual" which is the opposite of what the Mercury Service manual describes. There are 2 lines on the oil injection arm and I chose the mark listed in my original manual.

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