Johnson 15hp not running or idling right please help

A

ajohnson035

Cadet
Joined
Nov 28, 2008
Messages
26
I have a 94' Johnson 15HP outboard. I have been working on this thing for a few days now with no luck. I took it out the other day and it would not run at full speed it would only run around 7hp maybe. When I turned the throttle all the way up it would bog down and cut off and be a pain to restart would put blisters on your fingers restarting it. I went back home checked plugs they looked a little discolored so I put in a new set still did not help. I took off the carb and cleaned all passages out with carb cleaner and straw also blew it out with compressed air. I hooked it up to the water hose and it started and ran good but would not idle when tiller handle was turned all the way down however it ran great full throttle on the water. When I cut the motor off and waited about 5min it took 5-6 pulls to restart it which doesn't seem normal compared to other motors I've had. So i ran it again full throttle then it started messing up again it would not go full throttle and terribly hard to restart. I pulled the carb off again cleaned and blew everything out went back to lake and it took off like a rocket ran great for about 10mins then started messing up again wouldn't go full speed I'd say it would run around 8-10hp but not like it should. I have tried adjusting the needle valve on the top side of the carb that has a spring around it while running and idling and I have had no luck I don't know what position this should be in but i have tried all positions with no luck. I did at one point get the motor to idle low with adjusting this needle valve and it would restart on the 1st pull if you tried it right after you cut the motor off. However if you let the motor sit for a few mins and then tried it took 4-5 hard pulls to get it to start. I need some help please would taking the carb off again and rebuilding it help. I have only cleaned the carb I have not rebuilt it. I'm not sure what else to do so your help would be greatly appreciated. My email is ajohnson035@nc.rr.com thanks
 
M

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: Johnson 15hp not running or idling right please help

Hopefully you disassembled the carb soaked it in solution and got it clean like it should be.Is the gas good clean gas.Be sure the timing plate under the flywheel is rotating with throttle.They can stick it should be free moving.On some models the plastic cam that the throttle rolls on break be sure its ok,also the roller itself,.If your carb has a plastic top,be sure its not cracked anywhere especially around the needle area and be sure the packing (little plastic )the needle threads thru is ok.Check your fuel hose for leaking orings at the connections they often suck air when bad
 
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