I have come to the conclusion that my (relatively new - has 4 seasons on it) carb has a problem. The engine appears to run too rich:
1) Plugs are instantly sooty
2) Running under load at idle fouls the plugs in a matter of a few minutes to the point of stalling or having no power
3) Using a ColorTune spark plug (a wonderful thing), I can see that over all RPM ranges both in and out of gear that the mixture is very rich
In order to safely operate the boat, I have taken to making sure that whenever it is in gear, that I keep the RPMs at 1300 or above to make sure that I am running on the main jet which seems to keep the plugs operating OK. This does make for some interesting maneuvering though!
I have noticed that adjusting the idle mixture screw (from all the way in up to 6 full turns out) has NO effect on the ColorTune-visible flamefront color and no effect on engine RPM. While I am interested in the adjustable main jet as a good-to-have thing, I don't believe that it alone will solve the general mixture problem, especially at idle.
Any suggestions on tracking down the cause of the idle mixture screw having no effect?
Suggestions on tracking down a generally too-rich carb mixture?
And, before pulling the carb apart for general inspection and cleaning, should I need a full carb service kit on-hand?
Thanks in advance.
1) Plugs are instantly sooty
2) Running under load at idle fouls the plugs in a matter of a few minutes to the point of stalling or having no power
3) Using a ColorTune spark plug (a wonderful thing), I can see that over all RPM ranges both in and out of gear that the mixture is very rich
In order to safely operate the boat, I have taken to making sure that whenever it is in gear, that I keep the RPMs at 1300 or above to make sure that I am running on the main jet which seems to keep the plugs operating OK. This does make for some interesting maneuvering though!
I have noticed that adjusting the idle mixture screw (from all the way in up to 6 full turns out) has NO effect on the ColorTune-visible flamefront color and no effect on engine RPM. While I am interested in the adjustable main jet as a good-to-have thing, I don't believe that it alone will solve the general mixture problem, especially at idle.
Any suggestions on tracking down the cause of the idle mixture screw having no effect?
Suggestions on tracking down a generally too-rich carb mixture?
And, before pulling the carb apart for general inspection and cleaning, should I need a full carb service kit on-hand?
Thanks in advance.
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