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1986 Johnson 28hp bogging down, help please

N

notyepcars

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I have a 1986 Johnson 28 special on a pontoon that our family has owned for years. It starts and idles all day long ,as soon on a you start to give it throttle, about 1/3 throttle, it bogs an dies, if you are quick enough and pull back on the throttle, it wont die. It will restart immediately and idle great. I tried new fuel tank and hose with no change, and I put a basic carb kit in it with no change,. In looking at a breakdown of the carb, it looks like it as a fixed high speed jet. Do you think it is a carb issue? And do I need to remove the welch plugs and do a complete disassembly of the carb? Thanks
 
The most common cause of the bogging down problem is a clogged high speed jet... located horizontally in the bottom center of the float chamber... way in back of that drain screw. Clean it carefully with a piece of single strand steel wire.

Let us know if that cures your problem.
 
Had a similar issue on an older evinrude, just as it starts to bog, just give the choke a quick bump...assuming it has a remote elect choke. On mine, the thing would take right off from there. Not a permanent fix but would probably give some clues to the real issue.
 
I finally got around to installing the rebuilt carb with a new high speed jet, however, when installing it I broke off the nipple for the electric primer that mounts on the carb. The boat started fine and I sat in the back of the boat while my brother ran the controls. When I took the small 1/8" line primer line and held it into the carb, the engine ran great at wide open throttle. Now I am really confused, as I thought that is just a primer and not designed to run the engine, but it did. Is this primer designed to pump fuel into the carb during normal operation?? Thanks
 
With the hose OFF, the engine is drawing air through that broken nipple into the intake manifold area. When you put the hose where it belonged, that plugged the air leak and caused the fuel/oil/air flow to run through the carburetor only.
 
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