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20hp flooding

cdru

New member
Older 20 hp Mariner floods easy when trying to start. Also, after running wide open and then going down to idle, it stumbles and dies. Will not idle down without dying at any time. Could it be the float level or is there an adjustment screw, other than the idle screw, that could be out of wack? Thanks, cdru
 
Just noticed what appears to be another adjustment screw. It is located near the bottom of the carb on the starboard side. It is larger than the idle adjustment screw and has a spring on it. It is screwed all the way in. What is it for and could it be my problem? Thanks, cdru
 
If that's what I think it is, it's the idle speed adjustment. The newer 25s have electronic spark advance (as I found out the hard way!)

Jeff
 
If you have a side bowl carb (bowl would be on the left as you look at the throat), if that spring is located in line with the welsh plug on the side of the carb then it's the end of the throttle shaft (which looks like a blade type screw where it (sticks out) but is in fact simply a "cut" in the shaft which holds the spring - not a screw at all - you can gently turn it with a screwdriver and it should spring right back into position - that's the shaft the controls the butterfly in the carb and is not adjustable "at that point".

If it is forward of that (closer to the throat) then it's the bottom end of the the main fuel nozzle (but shouldn't have a spring).
 
The carb is on my work bench. I adjusted the float, but noticed on the lower port side a nipple that has nothing on it. Looks as if it should have a hose on it.?? It is right above the screw I asked about earlier. The carb is a TK 6G 65774 Thanks for the help.
 
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Yes, should be a "back draft tube" that goes from that nipple up to the float bowl cover (another nipple there - just to the right of a little air jet)
 
I found the spot where the nipple should be, but it is missing, just a hole there. What effect does this have on the performance of the motor?
 
At the extreme it could result in either a "flood" or a very lean fuel condition - most often it simply results in really crappy fuel economy and lots of carbon in the engine.

The internal pressure within the carb is controlled by an air backdraft jet (called "backdrag" back when your carb was new) which attempts keep things balanced for what the engine needs to run properly.

That little hose that is missing is like a vaccum line on your car - without it the air jet can neither feed or scavenge air pressure to the throat of the carb - so like your car, if you unhooked a vaccum line it would probably still run but you would notice anything from backfires to gutless performance...
 
Thank you very much for your reply. I think that is my problem as adjusting the float made no difference in the way the motor is running. I'll try to find a new nipple and get the hose installed. Thanks, cdru
 
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