Motor smokes a lot when cold

[JimMM]

I have a 1994 Mercury 200HP Black Max with low hours on it (less than 200) ... the plastic or brass gear that drives the oil pump started to deteriorate and the oil beep-beep-beep warning would go off intermittently. I removed the oil pump shaft and the wires from the rotation sensor and premixed my fuel 50:1.

The problem is, now when I cold start the motor, a cloud of smoke comes out of the engine until it warms up. The smoke is very thick and when I back out of the lift it all comes into the boat gagging everyone. I think it's also fouling the plugs since the motor does not idle reliably until I change the plugs. With new plugs it purrs like at kitten right a 750rpm all day. It expensive, and a pain, to keep putting in new plugs. I tried a small tank with 80:1 mix just for cold starts but it is a real pain switching tanks and I'm afraid some day I'll forget to switch back to the 50:1 tank before going to WOT.

Is there some way around this problem? Some people have suggested a synthetic oil or an electronic "VR metered" oil system. I've heard mixed reviews about using synthetic oil (more drag, hard on fuel lines and plastic fittings, etc) and the company making the electronic oil pump really likes it a LOT.

Second question ... I also heard that removing the OEM oil pump shaft could allow the bushing at the other end of the shaft still inside the motor to fall out and wreck havok in the crank or on the way out through the intake ports/cylinders/exhaust ports. The engine was run about 80 hours with the OEM oil pump shaft removed before I heard this caution. How can I tell if the bushing is still in its seat? If it's sitting at the bottom of the crack case is there an easy way to remove it? If the bushing is still in it's seat after all this time, should I worry about it. Should I just put the OEM oil pump shaft back in?

 

[Texasmark]

Re: Motor smokes a lot when cold

My 90 hp oil pump was spec'd at 80:1 at low speeds up to 50:1 at WOT. Obviously the pump put out a leaner mixture at low rpms and less smoke would result. I use a Syn blend I get at WW or at the Merc dealer. If readily available would run full syn. Probably Amisol or whatever their name is probably sells it. I buy the best oil I can get locally and the reason is to get the synthetic attributes. For me they smoke less than 100% dino oil; proven fact.

I too have a problem with my engine on startup and out to the no wake buoys and through the first punchout. I can't explain it but the interesting thing is that the rest of the trip, smoke is minimal, engine performance is stellar running just above the upper rpm rating, and starting is so fast that its started before you can get your fingers off the key.

On the washer you are talking about, I heard that too. I looked in my serv manual and it shows all the parts of the engine but NO washer. I have quite a few hours on my engine now and no problems other than a little extra smoke at idle. No biggie.

HTH,
Mark

 

[PuddleJumper]

Re: Motor smokes a lot when cold

I have a 1990 200 black max that still has the oil injection functioning. Since new it always smoked a bit cold. Last couple of years got a little bit worse. I know this is anecdotal but after switching to Evinrude xd 50 blend the smoke issue diminished drastically. FWIW

 

[Chris1956]

Re: Motor smokes a lot when cold

That motor should not foul plugs. Maybe the fuel pump is bad, allowing raw fuel into the crankcase?

 

[JimMM]

Re: Motor smokes a lot when cold

Did you mean Amsoil? I've used it in my vehicles for years and it is a very good oil. I didn't know they made an outboard motor oil. I'll try to find a dealer that handles it and give some a try.

I also can't find that bushing in any parts blowup. It is suppose to be press fit in the crankcase and takes the end of the shaft that drives the oil pump. I've heard that bushing can come out of it's press fit and rattle around in the crankcase and do considerable damage. It makes sense the end of that steel oil pump shaft wouldn't just turn in a hole in the aluminum block. You would think a bearing or at least a bronze bushing would be used. I also heard there is a kit of some kind to hold that bushing in place. I'm wondering if just reinstalling the shaft itself wouldn't do the trick. I guess it could cause more plastic teeth to shred off the drive gear on the crankshaft, but choosing between plastic shreds vs a bronze bushing flying around the inside of the crankcase is a no-brainer.

Do you run "just above the upper rpm rating" very often?

 

[JimMM]

Re: Motor smokes a lot when cold

Thanks, I just looked up Evinrude XD50 and it is supposed to be used on fuel injected motors. Would that make a diff on a carb engine?

 

[JimMM]

Re: Motor smokes a lot when cold

I don't know if I found the culprit but I was testing components on the engine that might affect idle mixture when cold and the enrichment solenoid valve appeared to be stuck open. When I removed the lower hose, gas was flowing out of the enrichment valve even though the key was not pushed in. I squirted some carb cleaner through the valve and now it seems to stop the flow of gas when not energized.

I haven't run the engine long enough yet to see if this will cure the fouled plug problem, but I'll check the fuel pump diaphram if it doesn't. I also checked the temperature relief valve and it appears to be working. I can blow air through it after the engine reaches about 100F.

Do you happen to know anything about a bushing in the crankcase for the oil pump drive shaft that needs to secured somehow if the oil pump and shaft are removed from the engine.