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2000 Yamaha f115TLRY won’t got to full throttle

Cplsteve

New member
Hello I don’t know if this has been addressed yet. I have a 2000 Yamaha f115TLRY starts up idles good and runs perfect at low speeds. When I give it full throttle it falls on its face. If I pull the throttle back slightly it will run at about 3800 rpm. I have replaced the following
all filters and separators
had injectors tested and cleaned
rebuild vst and new pump
low pressure pump
fuel pressure regulator
new plugs
new fuel
primer ball
impeller.
I have also smoke tested the fuel system and found no leaks. With the yds I checked tps and it’s at correct voltage. It’s not showing any faults either. Any help would be greatly appreciated.
 
My motor does not have that filter the only thing in that area is the pressure relief valve which was also replaced. All I can think is that it’s sucking air from somewhere, but where do I check before the vst or after?

the boat starts right up at first startup but after moving from one spot to another it has extended crank and then will start and idle and run good until you hit WOT. At that point the motor falls on its face. Like I posted earlier, I had the fuel pressure gauge on the motor while on the water. At idle about 36 psi. Increasing the throttle brought it closer to 40 to 45 psi when I hit WOT, it dropped down to 20 psi as the motor fell on its face.
 
Have someone pump primer bulb , when going to wot, and see if that helps. If it does help it will be mechanical fuel pump. And that fuel filter , u can't see it , it has a black cover over it.
 
So I’ve narrowed the problem down to a dead cylinder but can’t find the root cause. Went out fishing the other day and could not get the boat to jump onto plane. Rpms would only go to about 4200 and at idle and just in gear you could feel the misfire in the boat. I performed a lot of diag but I’m stumped.-While motor running at idle pulled spark plug boots 1 at a time. No difference in rpm on cylinder 3.
Performed compression test 135- 140 psi across the board.


  • removed injectors and checked for proper operation and spray, all appear good.
  • Replaced spark plugs as it has been a while.
  • checked for spark on all cylinders, spark present, noticed 3 would jump further then the rest.
  • checked stator via ohms and ac voltage, within specs.
  • checked timing, good.
  • while engine running removed injector connectors, still no change on 3.
The only thing left I can think of would be valve adjustment. Am I heading in the right direction or did I miss something???
 
Move the injector to a different cylinder and see if the issue follows.


chris, thank you for your response. I did as you suggested and the miss moved to cylinder one. I now have injectors on order. The part that really was dumping me was fine just had the injectors cleaned serviced flow tested and all that, so I did not even think that would be a problem.

steve
 
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