Wierd carb air problem Johnson 9.9

[Alby1]

Johnson 10RELENA 1992. Just bought it and the man said it wouldn't run right. I've tried everything to make it run right and it came down to the carb. It seems it's not getting enough air. It idles smooth. In the test tank it revs ok, goes right up to 5000 rpm. Put the cover on and it will go to 3000 rpm, running smooth. Give it more throttle and it acts like its starving for fuel. I played with it by propping a screw driver handle under either end of the cover to see what would happen and it still bogged down around 3800 rpm's and up. I didn't find any air restrictions in the cover. I looked and looked for anything that would restrict fuel. Checked for leaks around carb gasket. Squeezed the primer bulb, it was tight. As long as the cover is off, it runs great. Need some help, Please.

 

[ddennis]

Re: Wierd carb air problem Johnson 9.9

Check to see if the cover is pushing on any wires when you put it on. It doesnt sound like a carb/air issue to me as there is plenty of gaps and vent areas around the cowling to let enought air in for that small motor.

 

[Alby1]

Re: Wierd carb air problem Johnson 9.9

Thanks ddennis. That was the first thing I checked. Thats why I used a screw driver handle to hold the cover up. I also picked the cover up buy hand, and the further I raised it, the motor picked up rpm. I lowered it and the motor would begin to bog. I didn't list all the things I done to determine it was carb related, the post would have been to long.

 

[Indymike]

Re: Wierd carb air problem Johnson 9.9

I'm not familiar with the 9.9 but my 9.5 had similar issues and I found it to be exhaust leaking up the leg and into the cowling area....just a thought

 

[Alby1]

Re: Wierd carb air problem Johnson 9.9

FOUND THE PROBLEM ! There is a air vent (jet) on the side of the carb covered with a screen. After close examination, I found a greenish corrosion build up behind the screen, plugging the jet. I managed to get the screen off and cleaned the jet and airway. Runs great! Thanks to all who tried to help me. Hope I can return the favor.