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Excessive smoke


scalescratcher

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I own a 98 Johnson 115. I noticed late in the season of 07 that the motor seemed to smoke excessively at start up. Had it tuned up last spring but the smoking seemed no better. Once it's warm it is much better but at start up it's gotten me invited to join the mosquito control team.

Any thoughts?

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When you say at start up, do you mean everytime you start it up, or when you start up on the next trip out? Are you "over choking or priming" at start up.

when loading the boat onto the trailer at the end of the day, is it possible that the motor is tilted up pretty high? It may be loading up on you then and when you go to start it up the next time, it needs to burn off the excess gas.

Are you using a high quality 2 cycle marine oil?

Just a couple of things to check

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Thanks for the input Bruce! Other than the quality of the oil, which I don't skimp on, the rest of your eval is probably adding up to the cause. The smoking is usually worse at 1st start up and when sitting for any long length of time. I have to admit that I may have a heavy hand when it comes to priming and when I pull the boat from the lake I do tilt the motor way up. I'll keep your thoughts in mind.

Would an air leak in the fuel line cause any of the smoking issue? I replaced the primer bulb last fall.

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I had a '99 Johnson 115, should be the exact motor...

What specific oil are you using?

The Johnny smoked a lot at start-up also. It smoked a lot at idle, and "loaded-up" if I idled too long. It was not good..

I switched to synthetic Amsoil HP Injector shortly after buying the boat (1 year old), and the smoke was 1/2 what it was with typical TCW-3 injection oil. No more loading up issues..

I also noticed this same issue on my 175 EFI Merc too after I bought it 5 years ago. Switched it to Amsoil and hardly any smoke with that motor. Just a satisfied customer after years of use...

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Yes an airleak can a rich condition. When the fuel flow is impeded for whatever reason, the system will default to a richer condition. That being said, If you are only experiencing it at start up, I don't nessecarily believe thats what is causing your problem. Check all connections anyway, it certainly wont hurt.

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sounds normal to me. all 2 strokes are going to smoke a bit and after they sat for awhile or have been tilted up. i wouldnt worry about it. i got a old mercury 25 horse on my duck boat and lets just say there isnt a mosquito with in 30 ft around me! lol i usually run it a little rich but i dont really care that it smokes a little. will be getting a beavertail this year anyway.

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I would agree with the switch to synthetic. I owned a 99 johnson 50hp motor which did the same thing...switched to Amsoil, and that was the end of it... It still smoked a little more at start up, but nothing that would make you nauseated.

Steve

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I have the same motor as you Scalescratcher. I use the amsoil hp injector and am happy with it. Smokes noticeably less. Mine can be a little smokey on first startup too but it is what it is.

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I dont have an online source for you but when I switched over I just ran my oil tank down until my low oil light came on (make sure this works on your boat so you dont run it out of oil) then added the amsoil. There was less than a quarter tank of the standard when I topped it off with synthetic. This method worked good for me and motor didnt miss a beat. I beleive this method is what "The oilman" told me to do it.(Search my posts from last june and you can find the thread)

If you dont want to wait until you use up the remaining standard oil, just pump most of it out so that no air bubbles can get into the line and then add amsoil. A little hand pump like the one used for changing lower unit lube works good for this.

Hope this helps.

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Right - just run it down to the warning bell/buzzer/light, then top it up with what you are changing to. All of today's oils will mix, but best to minimize the mixing. Most boats it is difficult or very sloppy to drain the oil tank. Just never take a chance of running out.

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