20hp 4 stroke only runs with choke on.

[Zeltron]

Hello all!
I have a 2010 mercury 20hp 4stk that falls on its face when given any throttle. Ran great until on the river one time then just gave out while at full throttle. I have since changed the fuel filter, plugs, and oil filter. I checked the tank pick up and all is good. Good compression and combustion on both cylinders. Motor runs at full throttle while choke is engaged. But as soon as you take the choke off it dies. I was thinking fuel pump but I don’t know much about these motors. Any help would be great.

 

[racerone]

Clean the carburetor again.

 

[frustratedboater]

High speed jet is most likely plugged. Clean throughly like racerone advised and it should clear..

 

[Texasmark]

High speed jet is most likely plugged. Clean throughly like racerone advised and it should clear..

Don't forget a good dose of 100# compressed air with your cleaning and a little fine wire in the hollow tubes and Berryman's Chem tool for carbs and such.

Little fine wire: Remove the insulation from a piece of old lamp cord.. cut off a strand. Is Copper and soft but will work.