Excessive smoke

[ricksterpr]

Hi all, new to the forum.

Engine Mercury 240 v6

Upon turning on, excessive blue smoke came out of the exhaust. I mean a lot of smoke, enough to create a 10 feet high curtain. I idled away for about 15 minutes, and when accelerated, engine would no rev up higher than 5,000, all the while the smoke still trailing me. On middle and idle revs, no sings of failure. I decelerated and magically, the smoke disapperead and the engine started reaching full revs and speed on WOT. On my way back it happened just once again, but soon corrected itself.

A friend who has been around boats all his life bets 100% it is a clogged or water contaminated fuel filter. Strange since this filter has a sensor? I changed both filters and turned on at home, and smoke levels are at normal. Haven't had the chance of trying on the water.

Any suggestions as to the cause? I've read these symptoms are ussualy found on engines wearing out, and yes, my engine has around 250 hours. But my mainenance has been very very good, and 250 hours is not enough for a rebuild, in my opinion!

Side note - I have been using West Marines equivalent and just before this I filled with Quicksilver!

Your info is appreciated.

 

[ozziebob]

Re: Excessive smoke

Excessive smoke can only come from oil!!!!! Stale or old fuel causes this as when the engine has not been used for a long period the majority of the fuel evaporates leaving only an oily residue. when you start the engine it has all this excess oil to burn.. Just give it a good run. As for your worn engine lets think about our car at cruising speed. 100kph @ 250hrs is equivlant to 25,000km . YOUR ENGINE HAS DONE NOTHING !!!

 

[Texasmark]

Re: Excessive smoke

Sounds like good advice Ozzie. He said his maint is very good so I guess we could assume he keeps his oil changed. Maybe a good dose of Sea Foam in the fuel tank wouldn't hurt to limber things up like maybe a stuck ring or something.

Mark

 

[ricksterpr]

Re: Excessive smoke

Thanks for the replies. I'm starting to calm down and worry as much. Next Sunday I plan on launching, so I'll inform as to whether the problem persists.

Texasmark: I forgot to mention the engine is a 2 stroke, so it doesn't really recile the oil, but rather consums it. So as to an oil change as such (as in a car or 4 strokes), I only did it after break in...

 

[MikeV4]

Re: Excessive smoke

A good two stroke needs to smoke! All two-stroke engines I have had (from lawnmower to dirtbikes and outboards) all of them have been smokin' at engine start, especially when they have been standing a while. Just don't mix to much, to much oil is not good either.

 

[ricksterpr]

Re: Excessive smoke

Thanks MikeV4.

I know a 2 stroke will smoke as it consumes oil. But I'm talking a 10 feet high blue smoke curtain. It had never done this before (or since)...

 

[j_martin]

Re: Excessive smoke

I was surprised by how much mine smoked when I started it up after doing a compression check. A minute of cranking without starting can pull a lot of fuel in, and I imagine most of the gasoline evaporated off. 2 days later, when I launched it, I had a hard time seeing the landing for a minute.

A hard start, forgetting to reset the kill switch, kids messing around pumping the primer bulb, anything that would put in fuel and not burn it would cause this.

 

[gss036]

Re: Excessive smoke

I would be checking the oil tank to see if it is releasing the pressure, otherwise, your cylinders are full of oil as the pressure keeps pushing it through.

 

[phatmanmike]

Re: Excessive smoke

sounds normal to me. its gonna smoke! its a 2 stroke. if it sits for a while un-run, its gonna burn off all the remaining oil at startup. also they smoke a lot anyways. you have nothing to worry about if a 2 stroke smokes, its supposed too, the only thing that would make it smoke more is if it had too much oil. thats not a big deal, just watch how you mix it!

its when it DOESNt smoke, you need to start worrying.

if you dont wanna see the smoke, run a good full synthetioc oil.

you have a very expensive motor, stop using cheap oil. its a high performance machine and should be treated as such!

now go boating!

i run penzoils green 100% synthetic in my carbed merc 1994 200hp v6 and never have these problems.

 

[ricksterpr]

Re: Excessive smoke

[
you have a very expensive motor, stop using cheap oil. its a high performance machine and should be treated as such!

now go boating!

i run penzoils green 100% synthetic in my carbed merc 1994 200hp v6 and never have these problems.[/quote]

You are right. It seems that the mix of the Quicksilver and the West Marine brands created extra smoking upon starting. Somebody told me that although they are the same kind of oil, companies use diferent types of elements, and the mix could be the cause. As soon as I got to about 1/4 of the new merc oil, the smoking stopped. It now smokes in the normal way. It now is running great! I even gave it a good 52 MPH run, until my wife asked to slow down!!!

Thanks...

 

[wilde1j]

Re: Excessive smoke

Does the boat mounted oil tank stay pressurized after the motor is shut off? I shouldn't! You didn't say what model and year, but my '95 150's needed the check valve on the lower port side of the block replaced. The function of the check valve is to relieve oil system pressure and prevent oil from continuing to seep into the fuel after shutdown.

Smoking like crazy is NOT normal. Typically it stops after 10 to 15 minutes running and doesn't return until after the next protracted shutdown (hours or days).

 

[j_martin]

Re: Excessive smoke

Engine starting habits can contribute much to this problem. I found that I need to level my carb'd v6 completely before starting it. Then pump up the primer, hit the enricher for 1-4 seconds depending on the air temperature, advance the throttle a little, then crank. Before I found out exactly how to quickly start the motor, I would sometimes crank for 30 - 60 seconds, and she would smoke like crazy when it finally started. It should pop off in just a second or two if you got it right.
If you can't get it to do that, something's wrong.
Mine started balking a little. Needs carb kits and bleeder check valves serviced before spring. Those are normal maintenance items after years of service.


A reasonable amount of smoke at startup is normal, because the fuel left in the motor from the last shutdown has mostly evaporated, leaving the oil. It's actually a good thing for the motor.

I doubt that changing oil brands would cause it. I agree with mike. Don't cheat on oil quality. It isn't worth it.

hope it helps
John

 

[hkeiner]

Re: Excessive smoke

Needs carb kits and bleeder check valves serviced before spring. Those are normal maintenance items after years of service.

Hi, I know this is a somewhat old post but I wanted to know more about the BLEEDER CHECK VALVES mentioned in the earlier post. My questions are:

a) What is the proper service on the bleeder check valves. Replacement or removal/soaking in cleaner/reinstallation or other method?

b) How would a defective bleeder check valve cause excesss smoke, i.e., if it is stuck open or stuck closed?

I have a 1996 Mercury 150HP carbed motor and am trying to learn as much as I can about identifying excess smoke solutions. I have recently replaced two of the oil injection system check valves. These are the 1) 2psi check valve used to avoid fuel being forced into the oil lines, which is located between the oil pump and the fuel pump and 2) check valve that regulates the crankcase pressure going to the remote oil tank, which is located on the motor block and is connected to the hose going to the remote oil tank. Replacing these two check valves seemed to help a lot but I want to fix any and all check valves that may contribute to excess smoke.

Thanks for any input.

 

[RPH]

Re: Excessive smoke

Hi, I know this is a somewhat old post but I wanted to know more about the BLEEDER CHECK VALVES mentioned in the earlier post. My questions are:

a) What is the proper service on the bleeder check valves. Replacement or removal/soaking in cleaner/reinstallation or other method?

b) How would a defective bleeder check valve cause excesss smoke, i.e., if it is stuck open or stuck closed?

I have a 1996 Mercury 150HP carbed motor and am trying to learn as much as I can about identifying excess smoke solutions. I have recently replaced two of the oil injection system check valves. These are the 1) 2psi check valve used to avoid fuel being forced into the oil lines, which is located between the oil pump and the fuel pump and 2) check valve that regulates the crankcase pressure going to the remote oil tank, which is located on the motor block and is connected to the hose going to the remote oil tank. Replacing these two check valves seemed to help a lot but I want to fix any and all check valves that may contribute to excess smoke.

Thanks for any input.

I have a 1995 Mercury 150HP carbed with the same problem.
I have ordered the check valves and should install this week.
I have replaced the 2psi valve 2 times with no change in the smoking start up.
I now disconnect the fuel line to prevent the oil from backing down into the fuel line and mixing with the fuel causing even more excessive smoke and hard start ups.
Have you resolved your excessive smoking problem and what was the cure.
thank you