Thread: 150 Johnson Idle problem

Well it is a new to me boat. The year is 2003 model Hurricane Fun Deck with a 150 johnson and it has a very rough idle when cold starting and stalls when you throttle up if you arent quick about it. The choke does not seem to be working or it just isnt being effective in helping the motor idle. It doesnt seem to matter much whether it is warm or cold. At idle it behaves the same. The enging is strong when you get it to take off and there doesnt seem to be any problem running at speed or getting there. Its just at idle that it seems to be problematic. Would you start with decarbing it or check other things first? I am trying to learn as much as I can about outboards as I have never had on before. Any suggestions would be appreciated.

Thought I might run this up the ole flag pole again. Since I posted this the first time I did find a leak in the primer bulb fitting and fixed that and the motor ran like a charm at idle and low speed in gear as well. That sucess was short lived though as the very next time I took the boat out it was right back to square one. Same behavior as before. Makes me wonder if there is another leak that has developed or if there is something else going one here. Like I said I am new to this outboard motor thing so any pointers would be very helpful and much appreciated. I dont want to start out with a carb rebuild but that may be what is required. Would it be possible to run a concentraited batch of sea foam through the engine to clean it up some and maybe fix the low speed problem? Open for any suggestions.

I would start off with a de-carb. When you are done be sure to replace the plugs as they will need replacing. Here are the instructions. Decarbing Your Engine- The Process-HOW AND WHY - iboats Boating Forums

Pay particular attention to the part about not doing it on a nice clean driveway. It can be very messy. But it works. Check the rest of your fuel lines very carefully first. They should all be soft and pliable with no cracks.

Thanks a lot for the help. Thanks for the link. That should help cause Im playin catchup ball here with understanding outboard motors.