Honda irrigation pump motor not running well

[woodstover]

So I was asked to look at my friend's friend's pump motor not running. Starts and dies, Starts and dies.....
Removed the carb and was in the process of cleaning it out when I dropped it and broke the plastic part for the throttle linkage (damn). Ordered a new carb off of amazon and installed it. Thing is running awful. Surging at low and high speeds. Removed the new carb, dismantled and cleaned it out just in case, didn't find anything blocked. Running a separate fuel supply isolated from the tank. Still running the same. Sprayed carb cleaner around all carb mating surfaces while running and no improvement. I'm not able to get the idle down anywhere near 1600rpm and have the idle adj screw backed right out. Air mix screw is set at 2.5 turns
Should max rpm be around 3200rpm Idle around 1600rpm?
Idle jet is #79 drill and main jet is #70 drill
What am I missing??
Motor serial # GC01-2063426
I can't figure out how to attach pics, says they're too large to process

 

[Tiger Small Engine]

So I was asked to look at my friend's friend's pump motor not running. Starts and dies, Starts and dies.....
Removed the carb and was in the process of cleaning it out when I dropped it and broke the plastic part for the throttle linkage (damn). Ordered a new carb off of amazon and installed it. Thing is running awful. Surging at low and high speeds. Removed the new carb, dismantled and cleaned it out just in case, didn't find anything blocked. Running a separate fuel supply isolated from the tank. Still running the same. Sprayed carb cleaner around all carb mating surfaces while running and no improvement. I'm not able to get the idle down anywhere near 1600rpm and have the idle adj screw backed right out. Air mix screw is set at 2.5 turns
Should max rpm be around 3200rpm Idle around 1600rpm?
Idle jet is #79 drill and main jet is #70 drill
What am I missing??
Motor serial # GC01-2063426
I can't figure out how to attach pics, says they're too large to process

Always better to keep OEM carburetor if possible. Aftermarket carburetor sounds like it is running too lean (hunting and surging). Check for any air leaks as well. Only options are: carefully drill out pilot jet on new carburetor, order new OEM carburetor, repair broken plastic piece, gamble and order another aftermarket carburetor.

 

[woodstover]

I agree on always trying to use the original carb. That was the plan... But the main jet had already been damaged by someone else so it's not coming out in one piece as well as the drop damage from me. Idle jet o-rings missing also

I was of the same thought as you with regards to opening up the jets but I've just measured the originals and they are actually smaller. Original main jet: #73, new jet #70 so .004" larger, the original idle jet #80, new idle jet #78 so already .0025" larger. Maybe it's too much gas? The plug is black but not soot covered.

 

[woodstover]

Pictures

 

[Tiger Small Engine]

I agree on always trying to use the original carb. That was the plan... But the main jet had already been damaged by someone else so it's not coming out in one piece as well as the drop damage from me. Idle jet o-rings missing also

I was of the same thought as you with regards to opening up the jets but I've just measured the originals and they are actually smaller. Original main jet: #73, new jet #70 so .004" larger, the original idle jet #80, new idle jet #78 so already .0025" larger. Maybe it's too much gas? The plug is black but not soot covered.

Jets are smaller usually because the EPA is forcing companies to make equipment leaner in order to follow regulations. Engine’s don’t usually hunt and surge because they are running rich (too much fuel).

 

[bertsmobile1]

Some times there is no alternative to enlarging a jet
Idiot EPA regulations have engines running way too lean
This is fine if you a shoving snow around but a big problem on very hot days