I have a Johnson 9.9 that I had brought in for tuneup and lower gear grease change end of last season. I've only used it a few times this year and it ran great those few times. The other day I was out and noticed it stalled at idle speeds, but ran ok at highers speeds. luckily I got back to the docks, but as the trip went on it seemed to get worse, stalling when trottle was turned down near idle. What could it be? bad gas? dirt in fuel? Thanks, Steve
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Charlie Gruetzner
Not an expert But
I had a similiar problem last year. the problem turned out to be varnish in the carburator as a result of the build up form the gasoline. You may need the carb cleaned out and then whenevr you put it away for the day disconnect the fuel line and let it run itself dry.
I had a similiar problem last year. the problem turned out to be varnish in the carburator as a result of the build up form the gasoline. You may need the carb cleaned out and then whenevr you put it away for the day disconnect the fuel line and let it run itself dry.
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steven f.
carb
I too am no outboard expert but I have owned a crap-load of them over the years and nine out of ten times I had a problem with the engine it was the carb getting junked up from old fuel or lack of use. I understand that unless you put a lot of hours on the engine the carb will gum up eventually. I'd go that route after checking the plug's and fuel supply lines.
I too am no outboard expert but I have owned a crap-load of them over the years and nine out of ten times I had a problem with the engine it was the carb getting junked up from old fuel or lack of use. I understand that unless you put a lot of hours on the engine the carb will gum up eventually. I'd go that route after checking the plug's and fuel supply lines.
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Joe
pull the plugs
and clean 'em. Then follow Charlie's and Steve's excellent suggestions. Running two strokes at idle rpms for long periods will affect the carbon build up on plugs. Those type of engines perform best a 3/4 or better throttle. Bad gas can affect performance, so can too rich an oil/gas mixture. One other thing, make sure the gas tank vent is open. (Haven't we all done that before?)
and clean 'em. Then follow Charlie's and Steve's excellent suggestions. Running two strokes at idle rpms for long periods will affect the carbon build up on plugs. Those type of engines perform best a 3/4 or better throttle. Bad gas can affect performance, so can too rich an oil/gas mixture. One other thing, make sure the gas tank vent is open. (Haven't we all done that before?)
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Bill O'Donovan
More ideas
1. Smell the fuel. If it stinks, it's bad. 2. When you remove the plugs, yank the cord several times to clear the engine. 3. Keep a spare set of plugs handy for quick replacement, rather than sitting there cleaning the old ones. 4. I find weekly running helps keep the OB happy. 5. A cranky OB is worse than a cranky teenager, but at least you can always cache the engine.
1. Smell the fuel. If it stinks, it's bad. 2. When you remove the plugs, yank the cord several times to clear the engine. 3. Keep a spare set of plugs handy for quick replacement, rather than sitting there cleaning the old ones. 4. I find weekly running helps keep the OB happy. 5. A cranky OB is worse than a cranky teenager, but at least you can always cache the engine.
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Tom Monroe
I quit buying marina gas ...
... and most of my outboard problems went away. Often, their fuel sits in the tank all winter, and isn't fresh enough. Lots less expensive, too, if I bring in a gallon of my own once in awhile. Every time you run the thin, you need to run it long enough to get good and warm. Also, mine has a fule shutoff, which I close and let the engine die ... keeps the varnish out of the carb. Agree w/the other post ... plugs and carb. Tom
... and most of my outboard problems went away. Often, their fuel sits in the tank all winter, and isn't fresh enough. Lots less expensive, too, if I bring in a gallon of my own once in awhile. Every time you run the thin, you need to run it long enough to get good and warm. Also, mine has a fule shutoff, which I close and let the engine die ... keeps the varnish out of the carb. Agree w/the other post ... plugs and carb. Tom
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Dan McGuire
Vacuum Leak
I had to scrap a 9.9hp Evenrude because of a crankcase vacuum leak in the crankcase. It would not idle, but would run at high speed. The repairman did not think it was worth the cost. A two cycle must have good seals everywhere including the crankcase, carb, etc.
I had to scrap a 9.9hp Evenrude because of a crankcase vacuum leak in the crankcase. It would not idle, but would run at high speed. The repairman did not think it was worth the cost. A two cycle must have good seals everywhere including the crankcase, carb, etc.
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Pete
bad gas
Steve, me vote is for bad gas/gummed up carburator.Todays gas is junk and only has a shelf life of 3 to 4 weeks.For what it is worth here is what I do. I use a 1/2 dose of Stabil fuel conditioner/stabilizer and run gumout carburator cleaner in the fuel all the time. You may be lucky and be able to clean up the carb with a gumout treatment.Of course there might be something else going on here but bad gas is a big problem. Good Luck !
Steve, me vote is for bad gas/gummed up carburator.Todays gas is junk and only has a shelf life of 3 to 4 weeks.For what it is worth here is what I do. I use a 1/2 dose of Stabil fuel conditioner/stabilizer and run gumout carburator cleaner in the fuel all the time. You may be lucky and be able to clean up the carb with a gumout treatment.Of course there might be something else going on here but bad gas is a big problem. Good Luck !
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tom
start simple
with a motor. To state the obvious the vent cap was a good idea. But with that the motor usually won't run at all. Then check the fuel filter to see if it's gunked up. Then the spark plugs replace if dirty. Without a doubt I'd dump some of the gas in a clear container if a pool of water settles out then you know the problem. I always run my outboard at full throttle for several minutes every time I use it to burn off the plugs etc. My brother always stressed that a motor needs fuel,air compression and a spark to run. In my experience when they won't run at idle speeds it's been a dirty spark plug. Often running at full throttle for a few minutes will cure that problem. Simple motors can't compensate well for low speed use and are usually adjusted for high speed use. At high speed you need a relatively rich mixture of gas and air. This same mix is too rich for idle speeds. Some motors have a mixture adjustment and you should lean the mix for extended low speed operation.
with a motor. To state the obvious the vent cap was a good idea. But with that the motor usually won't run at all. Then check the fuel filter to see if it's gunked up. Then the spark plugs replace if dirty. Without a doubt I'd dump some of the gas in a clear container if a pool of water settles out then you know the problem. I always run my outboard at full throttle for several minutes every time I use it to burn off the plugs etc. My brother always stressed that a motor needs fuel,air compression and a spark to run. In my experience when they won't run at idle speeds it's been a dirty spark plug. Often running at full throttle for a few minutes will cure that problem. Simple motors can't compensate well for low speed use and are usually adjusted for high speed use. At high speed you need a relatively rich mixture of gas and air. This same mix is too rich for idle speeds. Some motors have a mixture adjustment and you should lean the mix for extended low speed operation.
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Mic fry
Trouble with idle
Hi Steve: Take out the mixture control screw and you will see inside of the hole a small jet that is you idle jet now take a small piece of "safty wire" and run it thru the hole. it sounds like that there is a small piece of dirt in that hole. Also wipe off the end of the needle valve (mixture screw) and put it back in watch the little spring so it doers not fall off then turn it down very lightly untill it stops then back it off two and one half turns after it starts adjust the mixture untill it runs and idles the best (it won't take much) good luck "MIC"
Hi Steve: Take out the mixture control screw and you will see inside of the hole a small jet that is you idle jet now take a small piece of "safty wire" and run it thru the hole. it sounds like that there is a small piece of dirt in that hole. Also wipe off the end of the needle valve (mixture screw) and put it back in watch the little spring so it doers not fall off then turn it down very lightly untill it stops then back it off two and one half turns after it starts adjust the mixture untill it runs and idles the best (it won't take much) good luck "MIC"
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Steve C
thanks for all the help/advise
Hopefully I can work on it this weekend, if the rain ever stops in the North east .. thanks all
Hopefully I can work on it this weekend, if the rain ever stops in the North east .. thanks all
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