Idle problem with 200 Johnson..

[fishinwrench]

  On 8/8/2016 at 7:55 PM, Bassin' fool said:

Ok so now I'm about to make myself sound pretty stupid, took the engine cover off in the driveway this morning and pulled the breather cover off the front of the motor to see if I could find which carb was leaking. Pumped the primer bulb twice and shot a stream of fuel out of the fuel inlet line about an inch from the pump, also had one plug wire that got pulled off when I put the hood on last time so I had no fire on one cylinder. The compression checked out good and even on all 6 

Expand  

Excellent!    Fix that, then verify full timer base movement and the condition of the throttle cam roller, then take her out for a spin.  

Happy Boating

[Bassin' fool]

The timer base traveled from idle position until it hit a stop (assuming that's the timing adjustment?) and the throttle cam roller looks like it's been recently replaced. After the fuel line replacement and fresh spark plugs she started up on maybe the second revolution without being choked and ran until it was at full operating temp without a single sputter or miss, and had MUCH better throttle response. Thank you very much for your help, and now I have a good excuse to take her out one night this week! ?

[Old plug]

That explanation of what happens with the shelf life was eye opening wrench. I seen a whole pile of fuel line that were clogged from use of E87. When they set for awhile without use that ethanol causes buildup in the fuel lines. This last time I had that problem the boat had sat over in sunrise beach for Cose to three months. When it came home I started it and it run rough. So I put a couple shot glasses of Sea Foam in the tank and that had th effect I'd breaking up all the hard crap in the lines and the stiff when into the fuel filter and really fouled up he whow. I am going to burn  E91 from here on out. It has preformed a awful lot better and I seem to use less fuel and have a lot more power. When you consider the cost of a can of Sea Foam when used as directed in your gas your paying about the same as E91. I have no doubt it is he proper thing in my 115 4 stroke.

 

[Bassin' fool]

Well I finally got everything put back together and got to get on the water for awhile last night. At full speed the boat performed flawlessly, I was back to running high 50's- low 60's. But I'm still having the same idle problem that I started with. The engine seems to idle alright but when I put it in gear and give a little throttle it will just sputter and die, it almost acts like its flooding itself not losing fuel like I had originally thought. It takes several times of starting up and dying before it will finally "pick up" and run. But after it's been ran at high rpm for just a couple minutes I can go back to an idle and it does great. Is the motor not warming up to operating temp? Not sure if this model has a thermostat or not.. 

[fishinwrench]

You do have a thermostat but unless it's getting overly hot, or not warming up at all, that's not your problem.

Do the cylinder drop test and see if any cylinders are idling weak (if they are you won't notice much change when that plug wire is removed).  If they all react equally then set your idle speed to 1100 rpm on the hose and go try again.  

If one or two cylinders seem weak then you either need fresh spark plugs (gapped to .030), or to have the carbs overhauled and re-synced.

On rare occasion, leaking exhaust seals will cause rough unstable idle, but usually carbon will build up and "reseal" those leaks on its own. 

[Bassin' fool]

  On 8/12/2016 at 4:07 PM, fishinwrench said:

You do have a thermostat but unless it's getting overly hot, or not warming up at all, that's not your problem.

Do the cylinder drop test and see if any cylinders are idling weak (if they are you won't notice much change when that plug wire is removed).  If they all react equally then set your idle speed to 1100 rpm on the hose and go try again.  

If one or two cylinders seem weak then you either need fresh spark plugs (gapped to .030), or to have the carbs overhauled and re-synced.

On rare occasion, leaking exhaust seals will cause rough unstable idle, but usually carbon will build up and "reseal" those leaks on its own. 

Expand  

I will try the drop test in the morning if I can find the time, if that leads me nowhere then I'll probably just haul it to a shop and have it gone through. If it comes to that I was wondering if you had a marine shop and where I could bring the boat to? If you can tell me all of this based on my VERY poor description of what's going on then I'd say you know your stuff! Thank you very much for all your help and advice 

[fishinwrench]

I do, and I'm in Gravois Mills (west side of Lake Ozark).   I'd be glad to work on it but I'm not here to pimp my business.  So in other words you're not gonna hurt my feelings if there's a decent shop closer to you.