johnson 15 idels and runs 3/4 but bogs at wot

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bubba3689

Recruit
Joined
Jan 23, 2011
Messages
1
Hi guys. I have been reading the forums for a couple weeks and has just been too lazy to register. i have learned so much already. well to the problem. i have a 1985 johnson 15hp. it will start on the first or second pull idle for days, then when i put it in drive it will bog down till i play with the choke and i can find a sweet spot for it to run at about 3/4 throttle. it will go full throttle perfectly then die after about 150 yard of WOT running. if anybody can help me out id really appreciate it. thanks in advance
 
SparkieBoat

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: johnson 15 idels and runs 3/4 but bogs at wot

fuel pump or dirty carb is my guess..also could be fuel line sucking air at one of the connections
 
L

levi_tsk

Ensign
Joined
Dec 26, 2010
Messages
907
Re: johnson 15 idels and runs 3/4 but bogs at wot

fuel pump and if i remember correctly the motor you have is got the small square pump and it is a ROYAL PITA to rebuild ....unless someone aready upgraded it
if its the small square pump heres the part number 393088
 
HighTrim

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: johnson 15 idels and runs 3/4 but bogs at wot

Could be the pump, could be the carb. Are the fuel lines original? Will pumping the fuel primer bulb keep the motor running smooth? What about if you take a spray bottle with pre mixed fuel and spray it into the throats while underway, will it keep running?
 
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