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1999 mercury 4 stroke with carb problems I think

C

Chewybmt

New member
Hello all and thanks in advance to the input I receive!!

i have a 1999 mercury 4 stroke with 3 carbs and they are kicking my butt.
I removed the breather and can see gas shooting out of the tall stem in the carb when I rev up the engine, but as soon as I let off the gas the gas will quit coming out even if it’s full throttle and the motor bogs down and eventually dies. If I keep messing with the throttle, I can see gas goin in and it continues to run. Not much I haven’t checked on this dude. New gas can, new lines all the way to the carbs too. Disconnected the line at fuel pump and it shoots out of it fine while running. It starts and idles fine. Plugs are clean and compression is 110 on all 3.

If someone can just give me a clue what to check next I’ll be more than happy to try it.
 
Low speed jets are most likely plugged on possibly 1 or more carbs. If you bave good spark on all cylinders and If compression is good. I would remove the carbs for cleaning
 
mechanicman said:
Low speed jets are most likely plugged on possibly 1 or more carbs. If you bave good spark on all cylinders and If compression is good. I would remove the carbs for cleaning
Click to expand...

I checked the compression again yesterday with the motor cold and warm and the throttle wide open and all 3 were 115.
What’s the compression supposed to be?
 
mechanicman said:
Pull the carbs apart and clean the low speed jets
Click to expand...

Gotta give u credit on that, I pulled them yesterday and put it all back together and used it today. Ran great full throttle and idle, still not perfect at half speed. So much better than it was.
Middle carb had 1 jet plugged
 
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