Home Forums Hunting & Shooting Hunter's Campfire Outboard Motor Problem

Run it at WOT on your boat with a healthy dose of sea foam, not the maintenance dose

I run SeaFoam in everything I have on occasion as preventative maintenance, swear by it.

At one time I had 20 outboards I used in a summer boat rental business.

I've always fogged my outboards at seasons end before I put them to bed and always had great luck with them.

Maybe it's over-kill, maybe not. It's worth the added measure to me.

The Ethanol effect on fuel lines is a blown outta proportion rumor.

The manufacturers of Ethanol have debunked these rumors.

All old neoprene fuel lines break down over time, if a line isn't brand new the dark colored residue will be present.

The new fuel line on the market today is due to EPA requirments for the blended fuel on the market we now have.
Ethanol is just one of many things now blended into our fuel.

EPA requires a certified fuel line to have a liner, of course as usual the bigger problem now is the liners breaking down and clogging fuel systems, causing leaks and consequently fires...go figure...


For a better understanding of modern fuel lines and blended fuels there is a good, short read here..

https://www.onallcylinders.com/2016/10/14/how-to-choose-fuel-line-material/

The comments are as informative as the article.

If the last gas mixture you used had ethanol in it that’s probably your problem. Even mixed with oil it will still varnish your carburetors. BTDT with a ‘85 150 Mercury, Yamaha ATV, Honda BigRed. If you are still using old fuel dump it. Add fresh non-ethanol gas mixture with something like SeaFoam in it. With the gas line disconnected pull the plugs and cycle the motor to blow the old crap out of the cylinders. Spray the inside of the cylinders with Kroil. A lot. Then load your carbs up with Kroil. Let it sit a day or so and spray Kroil into the carbs again. Next day try to start the motor. If it still gives the same problem pull the plugs one more time, cycle the motor, add Kroil again. Next day if it doesn’t run right take it to a repair shop or into the back yard. If back yard apply remaining gas mixture to interior of boat and over top of motor and lay a stream on the ground up wind 20 to 30 feet. Apply burning match to gas on ground.

Take it out on the water and run the piss out of it for a few hours

new spark plugs, sea foam , and the best new fuel you can find

That’d be a good guess. That, or just a stuck float (or bad float).

Also, any motors this old, that have been sitting, likely need a new water pump impeller, and a new fuel pump (or fuel pump diaphragm).

In that order.

Agreed. Sounds like time for a carburetor rebuild to me.

all it takes is a little piece of varnish breaking loose an winding up in the needle seat.
it is a lot like a stroke except it doesn't kill the motor.. it just gives you a heart murmur.

I am fortunate that I can easily find and buy real gasoline here with no ethanol. I know it doesn't solve the immediate problem with your outboard but once you get the fuel system cleaned and the timing set correctly for the octane fuel you plan to use. Try and avoid the ethanol. It separates and absorbs water and is corrosive to old plastics and rubber seals and gaskets.

Now that all the Sea Foam and ethanol gas mechanics have given you their diagnosis, I'll tell you what is wrong. The symptoms you are describing is whats known as a lean sneeze, very common on that era motor. You can try richening the air/fuel mixture and see if it will go away, but it almost always requires a carb rebuild.

Wonderful way to blow up a motor that is running lean.

Always better to strat with adjusting a carb that was running fine during it's last use or rebuilding the carburetor vs running a couple bucks worth of fuel/carb treatment through it and keeping your fingers crossed.

A guy's gotta start somewhere.

Yep. While it could be a “lean sneeze”, like Mirage 243 says, the black plugs the OP mentions make me think of flooding/rich. Like I said, could be float stuck open or bad float.

If lean, could be clogged carb or hung float. Could also be fuel pump diaphragm (hardened from years of fuel exposure), and carb is not getting good fuel supply.

Either way, the thing could probably use the carb cleaned out, a new fuel pump or fuel pump diaphragm, and then replace the water pump impeller, as well.

You can't take a plug reading off of something that has sat for years and has only been run on the hose, you have to put it under load. All 2 strokes will show super rich plugs after just running on the hose whether they are truly running fat or not.

Fat 2 strokers runnin?

😜

Similar to my advice for my father in law on his motorcycle.
And it was before ethanol gas. Plain gas goes to crap too
A couple burpy, coughing, sputtering passes, then it took
off. Ran perfect!

Was it run dry before it was stored 5-7 years?

That's not much of a problem to me....This is a problem! What you are seeing in the picture my son sent me a couple of weeks ago, the faint haze of smoke, is all that is left of a 1980 9.9 Evinrude that just prior to this picture being taken, was running fine. 16 feet of water with alligators. No oil sheen to mark the spot. There was no indication of it at all when searched for with a depth recorder that can see everything else in the area. I bought it new in 1980. It never took more than 2 pulls to start and ran like a top. I ran it dry after every use and did regular maintenance. It was a great engine that has found its final resting place evidently.