1996 Johnson 175 HP-idle problems

[Salty Dawg]

The engine runs great when first cranked and idles at around 800 rpm when in netural. After engine runs for a while and you pull it back into netural the engine surges between 800 and 2000 rpm. When I put the engine in forward or reverse while it is surging the engine shuts down. It appears the surging starts only after the engine has been run for 30 minutes or more. All 6 carbs were rebuilt by the dealer approximately 12 month ago. The engine runs great at all speeds except for idle. Thanks for any help in solving this problem.

 

[Joe Reeves]

Re: 1996 Johnson 175 HP-idle problems

Is the surging like you would slowly increase the throttle, then slowly decrease it? A slow up and down surge.<br /><br />Or is the surging like a couple spark plug wires were suddenly yanked off, then later both put back on at the same time. A sudden instant type up and down surge like turning a switch on and off.

 

[Salty Dawg]

Re: 1996 Johnson 175 HP-idle problems

The surging is instant type. It will jump up to 1500 or 2000 rpm and may stay for a while and then drop back to 800. If I can get in forward without the motor shutting down it will respond beautifully. As I previously stated the motor has to be good and warm before the surging starts. When I first put it in the water and the motor is cool no surging occurs. I've tried to duplicate the problem at home on the ear muffs, but to no avail. It idles between 800 and 900 rpms and no surging.