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Smoking excessivly

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sdavis555

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"My 1979 Johnson 150 seahorse,

"My 1979 Johnson 150 seahorse, smokes ALOT when I crank it up and after a while 10 to 15 minutes it clears up, what gives , I am not making many friends at the ramp. I did notice that I have a lot of black fuel oil running out of my upper cowl when it is tilted."
 
extra smoke on startup is norm

extra smoke on startup is normal and almost embarrasing. It usually lasts for 10 to 15 seconds on my boat.If you have to idle for extended time before shut down the oil drains down and on start up is thrown into the air for extra lubrication and that is a good thing
 
"Skip,
You are correct that V

"Skip,
You are correct that VRO did not appear until 1984. Your motor originally was and always will be a pre-mix monster.

Here are a few suggestions that may help:

1) Check engine compression. It may be a case where you have worn rings that are allowing excessive blowby until the engine warms up.

2) You may also have sticking rings due to carbon buildup. In this case, you need to de-carbonize the engine. Get a can of Deep Creep (Seafoam in a spray can) or Bombardier Engine Tuner. Take the boat to the lake and make a 5 or 10 minute run to get up to full operating temperature. Pull the boat on the trailer but leave the engine in the water. Run the engine around 1,000 to 1,200 RPM while spraying the can(s) of decarb solution into the carburetors spending about 5 seconds on each carb throat. Spray this stuff until the entire can is gone, or the engine dies. If you choose, you can also remove your spark plugs and spray some in the cylinders for good measure. I have read that some guys will turn the flywheel by hand after spraying in the cylinders (with the plugs out obviously) to get as much penetration on the rings as possible.

Pull the boat out of the water and let the engine set for a good long while. Overnight is even okay. When you start the engine again it is going to smoke like a pile of wet leaves, which is okay because you're burning off the dissolved carb deposits.

Then, every few tanks, you should add a can of Seafoam to your fuel to help keep carbon deposits from building up.

3) Run a high quality oil. This year I ran mostly Evinrude XD50 oil in my '79 Evinrude 140 and there was significantly less smoke that when I ran XD25 or even Penzzoil 100% synthetic. I have also ran Amsoil HP Injector oil and that produces slightly less smoke than the XD50.

4) Use a graduated mixing bottle. Getting too rich on your oil will easily cause excessive smoke. I bought a Seasense mixing bottle from walmart like this one: http://ec1.images-amazon.com/images/P/B000FZ1ZWW.01._SS500_SCLZZZZZZZ_V66516250_ .jpg"
I just estimate from my fuel guage how much gas I'm going to put in, then using the bottle I measure the appropriate amount of oil, pour that in the tank, and then fill the fuel. The nice thing about this method is it takes a lot of guess work out of adding oil and makes sure you have the exact amount of oil needed.

5) Check your carbs. You may possibly have a bad needle valve that's allowing excess fuel to flow in the engine.

KJ"
 
"Good needles will have smooth

"Good needles will have smooth even edges and a sharp point on the end. Worn needle valves will have grooves in the edges. If you have had this motor a long time and have never rebuilt the carbs, then maybe this would be a good project for you. The rebuild kits come with new gaskets, needles, seats, and floats.

But also keep in mind these old pre-mix monsters are prone to smoking. I know it's kind of taboo in this day and age, but it's simply the nature of these old beasts. As I have said though, if you take the steps I outlined above you may be able to minimize the amount of smoke.

KJ"
 
"Skip,

You might have a pro

"Skip,

You might have a problem with the oil circulating system, causing oil to pool somewhere in the block.

Tony"
 
"Skip,
The above are all reas

"Skip,
The above are all reasons for the smoking.
Since you have that big of an engine I take it that the engine is in the up position while the boat is on the trailer. If so then you would see fuel in the bottom of the cowl if the carbs were leaking.(the bad needle & seat)

If the compression is good and the boat runs well at idle and at the correct rpm at wide open I doubt the rings have any type of carbon problem.

This is my opinion but the old spray a new set of piston rings into the engine does more harm than good. If some of the carbon stays in the rings it can cause damage to the cylinder walls.

This is just a guess but I'd say the fuel has more oil than it should. Over time the mix can get rich if you add just a little more oil than the amount needed each time you fill up. It's easy enough to have happen.
If you have someone ride in another boat a couple a hundred feet behind and to the side from you they would see that there was smoke trailing you if the mix is too rich.
The engine could be smoking up a storm and you would not be able to see it from inside the boat when the boat is on plane. But other boaters will see it.

When the engine is cold it has a hard time burning the extra oil so it smokes more until it warms up but it should only somke for a few seconds not long enough to kill off all the bugs and nearby fisherman.

Try mixing the fuel as close as you can and see if the smoking gets better. When you add fuel try and get it as close to full gallons as you can. If you think it will only take a little more than 5 gallons quit at 5 gallons. It makes it much easier to measure the oil needed.

If you are buying pre-mixed fuel from the dock then stop until you have made sure the fuel in the boat is the correct mix.
Having worked around many marina's I have seen fuel delivered then someone guess at how much oil was needed. This can at times put more oil than needed or less than needed. Most of the time they would add a little more to be on the safe side. Marina's also do not always use the best oil in the world.

From what you said I doubt there is anything really wrong with you engine other than it has more oil in the fuel then needed.

A few fill up's with the correct mix will tell.
Good luck."
 
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