motor runs strong with choke out weak without

NYGiants

Chief Petty Officer
Joined
May 3, 2009
Messages
582
i have a 2001 johnson 25hp tiller pull start. i had noticed a sluggish difference of 5mph on the boat. (14ft aluminum boat) it has a primer knob (like a choke but not) and when you pull it out the motor runs great and like it did when i bought it (april) it has great compression all equal numbers carb was completley rebuilt in april by a marina and cleaned about a month ago (water in fuel) my outboard guy mentioned it could be a failing fuel pump? he said to squeeze the ball with the choke in and see if that helps which it didnt. any ideas?
 

NYGiants

Chief Petty Officer
Joined
May 3, 2009
Messages
582
Re: motor runs strong with choke out weak without

could i just run seafoam in the gas?
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: motor runs strong with choke out weak without

Start with the carb and go from there.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: motor runs strong with choke out weak without

flooding a warm motor with gasoline by activating the primer should shut it off immediately. The fact that it doesn't, means gas isn't getting from the carb to the cylinders.

if the fuel pump fails, the primer/choke would have no effect cause there wouldn't be enough gas in the line anyway.

you've managed to pick up some gunk from somewhere, and it's lodged in your carb.

ethanol-blended gasoline didn't just happen to recently appear at gas pumps in your region, did it?
 

lmuss53

Lieutenant Junior Grade
Joined
Sep 9, 2008
Messages
1,227
Re: motor runs strong with choke out weak without

Since this is the third time for cleaning out your gunked up carb, you should probably look at the tank and hoses to see where the gunk is coming from. You should also think about putting a filter or fuel/water seperator somewhere in the line.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: motor runs strong with choke out weak without

agree, COMPLETE carb cleaning w/ rebuild kit.
 

NYGiants

Chief Petty Officer
Joined
May 3, 2009
Messages
582
Re: motor runs strong with choke out weak without

flooding a warm motor with gasoline by activating the primer should shut it off immediately. The fact that it doesn't, means gas isn't getting from the carb to the cylinders.

if the fuel pump fails, the primer/choke would have no effect cause there wouldn't be enough gas in the line anyway.

you've managed to pick up some gunk from somewhere, and it's lodged in your carb.

ethanol-blended gasoline didn't just happen to recently appear at gas pumps in your region, did it?

no it didnt and the hose is new and all bad gas was taken out of the tank and replaced with 3 gallons of premium. when it becomes cold it sounds as if
its going to go. after 15-20 pulls minimum it will start. seeing as how i paid 160$ for that work ill take it back and get it fixed
 

NYGiants

Chief Petty Officer
Joined
May 3, 2009
Messages
582
Re: motor runs strong with choke out weak without

took it out again, the only difference was i ran the motor out of gas last time after using it. this time it started 2nd pull and ran like a top. boat ran around 25kts which is what it ran pre all the problems.
 

lmuss53

Lieutenant Junior Grade
Joined
Sep 9, 2008
Messages
1,227
Re: motor runs strong with choke out weak without

Whatever was there is gone. Kind of like passing a kidney stone.
 
Top