Mercury 4.0 Problems

[VASailor10]

Hi all,
The other day after entering the cove in which i keep my Catalina 22. I fired up the motor. I had a full tank of fuel, and after about 2 minutes under power the motor cut off. The problem persisted several times with the running time decreasing each time i fired up again. I sprayed some carb cleaner in the carburator and on the spark plug to clean. However, after doing this the motor would not even start. I have purchased a new spark plug and have not installed it yet. Do you think this will solve the problem, or should I look elsewhere.

-Spencer
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Suprise
Catalina 22

[labatt]

Does it rev up and down without you touching the throttle? If so, it may be your carb is gummed up with the wonderful ethanol blended fuel.

[VASailor10]

It was reving pretty high in neutral even with at low throttle. The cutting off also occured over all speeds. How do you check for a spark?

-Spencer
___________
Suprise
Catalina 22

[bentmast]

Sounds like you're not getting fuel too or thruogh the carb. Try loosening the cap on the fuel tank so it can vent.....If that doesn't work, drop the float bowl and check to see if the needle is stuck. I'm having a lot of trouble with the float needle sticking on my 4-wheeler becuase of the ethanol in the gas.

[bentmast]

Pull the PLug, connect it to the spark plug wire and ground the base of the plug to the motor........Turn the motor over and you should get a nice blue spark. you only need to turn the motor over for a few seconds to test.
If this is an old tank of fuel, replace the fuel before you start pulling your hair out. It might be that simple.

[sailingdog]

The symptoms do sound like a fuel tank with a closed vent.

[VASailor10]

I will try those.

Thanks,
Spencer
___________________
Suprise
Catalina 22

[labatt]

We had the same problem this past weekend - it would start and then die within 30 seconds. It would randomly change throttle speed. We took the whole thing apart and it turned out it was the carb was gummed up with ethanol blend fuel. We hadn't drained it at the end of last season. We haven't cleaned it out yet but we'll be doing it this weekend. On the other hand, the other reason could be a closed vent. It does sound like that too

[Sailormann]

There is a product called "Seafoam" that is great for dissolving fuel deposits. I used it on an ancient Mercury OB that I had for a while, which didn't like to start after sitting idle for a couple of weeks. The first time I used it, I sprayed it into the carburetor, removed the spark plugs and sprayed it into the cylinders, and let it sit for 24 hours.

It took quite a few pulls to get it going the next day, but it fired up and ran more smoothly than it ever had. After that, I used to give it a couple of squirts whenever I was going to be away for a while, or putting it away for the winter.

Sea Foam

[camaraderie]

Stuck float switch...remove the carb bowl and spray with carb cleaner. Change the plug too.