Suddenly Started Smoking at Startup

[lncoop]

I have a 2002 90 horse two stroke Merc on my party barge. The last couple of times out (week or so between trips) she's smoked quite a bit at initial start up. Once she's warm the smoking stops and doesn't reoccur for the rest of the day, weekend, etc. I'm not having any performance issues and she's not at all hard to start. In case it matters, for various reasons the motor has been tilted all the way up to the point that oil has spilled out of the reservoir a couple of times in days prior to the smoky startups. Is it possible the smoke is the result of the spilled oil burning off? Also, if it helps, here's my starting method. Before turning the key I disengage the shifter (push the button) and run the throttle to wide open a couple of times, each time leaving it open a few seconds, then I bring it back to idle and turn the key while pushing in. I read somewhere (on here I think) that was the way to do it. Thoughts?

 

[Killafornia]

Re: Suddenly Started Smoking at Startup

Mine does that too sometimes. Usually when I drop the motor down from the up position after a night on the can. I think it's just excess 2stroke oil burning off? It never bothered me. Just embarrasing cause it's usually when someone comes by.

 

[joed]

Re: Suddenly Started Smoking at Startup

What is the purpose of running the throttle wide open before starting the motor? I don't understand what that accomplishes.

 

[lncoop]

Re: Suddenly Started Smoking at Startup

What is the purpose of running the throttle wide open before starting the motor? I don't understand what that accomplishes.

My understanding is that primes it. Don't know if it's true, but I just checked Mercurymarine.com and they advise to advance to quarter throttle before starting, but apparently that's only recommended when experiencing starting trouble. I'll skip the throttle advance next time and see what happens.

 

[j_martin]

Re: Suddenly Started Smoking at Startup

Probably what is happening is the check valve feeding pressure to the boat oil tank is failing. It should deliver about 2 lbs when engine is running, and bleed it off in a few minutes when the engine stops. If it doesn't bleed the pressure off, it forces 2 cycle oil through the pump and into the fuel hoses to the carbs. Next start is way rich on oil.

That's why it happens only the first start of the day.

About 5 minutes after engine shut down, crack the fill cap on the boat oil tank. If you let off pressure, the above said check valve is bad.

hope it helps
john

 

[lncoop]

Re: Suddenly Started Smoking at Startup

About 5 minutes after engine shut down, crack the fill cap on the boat oil tank. If you let off pressure, the above said check valve is bad.

hope it helps
john

I've done that, last weekend in fact, in order to top off the reservoir (fill cap is on top of motor) and have not noticed any pressure escaping. It wasn't very long afer shutdown though.