smoky johnson

[need 2 fish]

i have an 87 johnson vro 140 that the oil injection has been disconnected and am mixing good tcw3 oil in the gas at 50 to 1. the motor starts and runs great but leaves a major "soot" like line at water level on the transom and sides of the boat. plugs are new and premium gas is used, lower unit rebuilt and water pump replaced last year. could this be a carbon build up from the previous owners maintenance and would the omc product "engine tune" fix / reduce the problem? the soot seems to be coming from the two ports below the cover on the mid section at the stern of the motor. any help will be appreciated.

 

[KT64TM]

Re: smoky johnson

are you sure 50:1 is the correct mixture?? thats what i run in my '64 johnson.<br /><br />seems a lil oilrich to me

 

[wilde1j]

Re: smoky johnson

50:1 is correct for that motor. Make sure the mix is correct and that fuel /oil get properly mixed. Before I used oil injection, I used a large funnel that I pumped some gas and slowly added the oil to make sure it's properly mixed. You don't need premium gas at all; 87 octane is fine.<br /><br />Does the motor smoke visibly after it's fully warmed up or just at start up? OMC Engine Tune will get rid of carbon buildup and can't do any harm, and will cause a good bit of smoking for a few minutes when the engine is run the first time after the treatment. That's good, since it's a sign that carbon is in fact being expelled.<br /><br />Visible smoking after warmup is a sign that either the fuel/air mixture is too rich or there's too much oil in the gas.

 

[need 2 fish]

Re: smoky johnson

i have been told by a johnson dealer 50 to 1 is the correct mixture, i switched to 93 octane in hopes to remedy the problem, no such luck. the engine smokes a while at start up but nothing after it warms up which i thought to be normal but i must kill the engine if i'm picking someone out the water at the stern or the fumes will knock you out. good compression on all 4 cylinders so i'm clueless. Does anyone know what the two ports at the top of the mid section right under the cover at the stern of the motor are for? when i pick the boat out the water this is where the soot seems to be coming from, it covers my mid section and transom heavily. the air mixture is something i have not looked into, going to get a manual ordered today to tinker more confidently. if the air mixture was off though i would think i'd suffer from performance problems like bogging down. motor runs great 18 foot c.c. hydrasport turning 5500 rpm at 40 to 43 mph.

 

[need 2 fish]

Re: smoky johnson

o.k., did some searching here and might have found a source but no solution to my problem and need ya'lls help. the two ports appear to be exhaust relief ports so when the motor is at idle the back pressure from the exhaust at the prop has a place to go. with that said could there be an exhaust restriction of sorts and where and how do i find it?

 

[Solittle]

Re: smoky johnson

Need - Time to decarb the motor I think. The soot you describe is normal. Using premium fuel is actually not the best for your engine. Use the 87 octane that OMC specifies.

 

[need 2 fish]

Re: smoky johnson

thanks for the advice, hope the magic in a can works. will post results after this weekend. one other thing, since this has never been done to my engine before and with the ammount of exhaust i'm experiencing, would doing this twice in say two weeks be beneficial or detrimental?

 

[unseaworthy]

Re: smoky johnson

I agree with the others that it sounds like you are running rich. Double check that air/fuel mixture and oil fuel ratio. I also agree that you shouldn't run mid grade or premium gasoline in an outboard. 87 Octane or below only. It is absolutely normal, even for a new outboard, to smoke a great deal when it's cold. If it dicipates when it's up to temperature, then it doesn't sound like you have a fuel problem. Your suit may be an exhuast problem of some kind. Good luck.