Welcome! Need support, you got it. Or share you ideas and experiences.
I have a 28' pontoon with an 88 evinrude 48 h.p. on it , at the beginning of the summer it ran fine, only stalling sometimes when I was going from forward to reverse, as the summer went on it started surging at half throttle, getting harder to start(warm or cold), and would not idle at all . I rebuilt the carbs, the fuel pump ,and put new plugs and fuel filter in it, and it runs just as bad. Is it possible the reeds are bad in it? How do you tell when your reeds are bad? There is no adjustment on the carbs, but if you stick your hand over them, the engine picks up, and smoothes out then smokes, and dies. The way it's running now I will be lucky to get it back on the trailer this winter. Please help.
I think that Tailgunner is right on the money. Just some advice however - don't perform the carb covering test too often, can lead to causing more problems down the road!
Broken or worn out reeds on a 1988 could be possible but is unlikely - you hope!. The only way I know of testing this possible problem without opening the motor up is by increasing the oil to gas ratio. This causes the fuel to be less viscous within the motor and less likely to slip past the reeds and causing a floading condition that you may be experiencing. If your motor's symptoms subside with a higher mixture (16:1) then the reeds could be a possible cause... but try the carbs first and remember that this test above should be used only for a short duration - otherwise you'll have some seriously fouled plugs!
What you mention in your message leads me to believe that you have gummed up main jets in carbs. When you put your hand over the carbs it creates the same condition as when the choke is on. It cuts the air and the motor is running really rich on almost pure gas.This indicates a lean cond. most commonly caused by stopped up main jets. or improper float settings. or just a mal adjusted carb. I'd bet on the stopped up mains in this case.
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