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Johnson 1991 28hp SPL problem

J

jft

New member
I have a 1991 28 H.P. Johnson engine and was fishing on a lake. It had been running fine all week, and suddenly, when I went to full trottle, it would just bog and slow down. It still ran fine at about half throttle, but when go to full it would slow down. I could choke it and it would surge somewhat, but would not go full out. It starts fine and runs good up tp half throttle. When I got home, I drained all the fuel in the tank and carb bowl. Looked good, no water or trash. I took the fuel tank screen off and it too was clean. It has new spark plugs and fuel pump. Any suggestions would be appreciated. Thanks
 
Re: Johnson 28 SPL problem

Either a fuel restriction, carb issue, or fuel pump issue. I would start with a new fuel line and bulb, and see if that solves the problem.
 
Re: Johnson 28 SPL problem

take a thin peice of wire and clean the high speed jet on the carb see if that works
 
Re: Johnson 28 SPL problem

when this happens, pump the fuel bulb, if the problem goes away while your pumping the bulb it's the fuel pump, if not then look at the carbs.
once it cools off does the problem go away?
 
Re: Johnson 28 SPL problem

I pumped the bulb while trying to run at WOT and it was completely firm. Was able to pump it a little but no change. Ran on the trolling motor for quite a while and tried the engine again, also no change.
 
I have the same engine and the same problem. Rebuilt the solenoid and put on a new fuel pump. Now it only starts with starter fluid and plugs remain dry, which can only mean it’s the carb., I suppose.
 
Model number is located on side of mount and has been partially rubbed away. Best that I can do is "Johnson 28 SPL 1988". Currently, I have; 1) New fuel pump. Verified fuel getting to carburetor bowl. 2) Freshly rebuilt solenoid. Verified to actuate. 3) Fresh gas, properly mixed 50:1 ratio. It was running at idle before I began working on it. I sprayed a generous amount of carburetor cleaner so maybe I dislodged something. Now it doesn't start unless I use starting fluid and only it runs for a moment. This has to be a blocked orifice in the carb. I'm running out of options. Will remove and inspect it tomorrow and let you know if I find anything. I will start a new thread, as soon as I figure that out. Thanks.
 
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