1975 Johnson 15hp: stop & start problems

[DeepSix]

My 1975 Johnson 15hp motor usually starts and runs pretty good. Problem #1: On occasion however, it may not want to stop when I push the kill button. I end up having to pull the choke on and lower the throttle to minimum to stall it out. I've checked the continuity of the button circuit with an ohm meter.....all seems ok. Problem #2: Occasionally when starting, the engine will immediately race to full throttle, even with the setting still in the start position. Stopping and then re-starting will usually correct the problem. Any ideas/comments are welcome.

 

[20/20]

Re: 1975 Johnson 15hp: stop & start problems

Not sure about problem 1 if you've checked everything and found no problems. Some one ripped the switches of mine so I have to use the choke to shut it down.<br /> <br />Problem 2 I'll take a stab at. I know when 2 stroke engines run out of gas they like to rev up. So if your engine were to have a sticky float it may not be getting enough gas right away. Try cleaning the carb and maybe even a rebuild if one hasn't been done in awhile.

 

[DeepSix]

Re: 1975 Johnson 15hp: stop & start problems

Thanks for your reply. A sticky float is certainly a possibility since the motor isn't used through the winter months. I always use Stabil....but it may just be time for a carb rebuild.

 

[CabinCrusierMark]

Re: 1975 Johnson 15hp: stop & start problems

Something is definatly stoppin' up ur carb. Remove the carb and go through carb with a fine tooth comb. A little tip, use small fishing line to dislodge blockages or buildups in those tiny little fuel passage-ways and finally spray clean or better yet use a carb dip. If this doesnt solve the problem, check out it's reed valves and make sure they're workin right. List of possible problems;
-Carb blockage (odd throttle problems)
-Reed Valve issues (rough running)
-Spark Plug fowling (the stopping issue)
-Fuel Pump
-Possible Bad fuel
-Primer Bulb (fuel line) or clogged intake line inside fuel tank (they've got a little screen)

Good luck...