I have a 1998 mercury 8 hp 2 stroke outboard. It has been used every weekend. I have not used it in 3 weeks. The engine will only start when I spray fuel in the air intake. It runs for a minute or so than dies. Is it possible that the carbeurator is gummed up after 3 weeks and if so how do I repair it.
Make (of engine): mercury
Horsepower: 8 hp
I have replaced the primer bulb and line from the gas tank. When I remove the fuel line from the carb and prime the bulb fuel runs through it. I sprayed sea foam in to the air intake and the engine will run until this burns up than dies. It appears that no fuel is getting to the carb but not sure.
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Does it stay running if you continiously pump the primer bulb after starting?
No it does not
Now when it does run, does squeezing the primer bulb as its running make the rpms increase or deacrease?
No it appears that the primer bulb does nothing, has no affect.
Then you are looking at a clogged up carb. (or semiclogged carb).
On the inside of the carb there are different circuits for idle speeds, off idle speeds, and high speeds.
The idle speed jets and circuits are extremely small on the inside of the carb. Smaller than the outside diameter of a small sewing needle. When you get just a little bit of dirt inside of the carb, the idle circuits are the first ones to clog. When they do, the engine will be (or impossible) to start,not idle, and not stay running.
What usually does it on the small 2 strokes is that when you premix your oil. Over the course of a few weeks of sitting. The fuel in the carb's fuel bowl evaporates, but the oil does not, and the oil gums up the jets.
When we clean them in the shop. We take the carbs off the engine and bring them to a workbench where we fully dissasemble them. Then we clean out every little hole and passage with spray carb cleaner followed by high pressure compressed shop air. When we are done we put them back together with new carb kits and reinstall them.
Now if they are very dirty. Then we send them off to a carb shop with an ultra sonic carb cleaning machine. The ultrasonic is like a big jewelry cleaner just for carbs. It works the same way a Dr would use an ultrasonic machine to bust up a kidney stone. It cleans out the passages that you just cant get to.
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Relist: Answer quality.another mechanics opinion
Hello. I agree with the expert you were talking with. If your able to get the motor started by shooting gas down the carb but it won't start on it's own then you need a carb cleanout and probably a primer pump repair kit( this is the pump that shoots fuel directly to the intake when you pull on the black knob. The diaphrams eventually break down and don't pump any more) also make sure that the fuel inlet needle isn't stuck and not allowing fuel to enter the bowl.