Yamaha 115 HP 2 stroke running slow/out of the water :(

[saltwaterlife]

Hi all, I have a Yamaha 115 HP 2 stroke that use to get 40 MPH now barely 15 MPH. Engine start good. When i engage, the Prop turn normal but not able to go over 15MPH on the water? do you think I need a new lower end? I have only 110 hours!!! could it be possible? The engine sound a bit different too.
Out of the water..

 

[BaileysBoat]

Re: Yamaha 115 HP 2 stroke running slow/out of the water

Not a lot to go on but check for a spun prop, assuming the Yamaha is running ok? What are the rpms WOT?

 

[dvalbenni]

Re: Yamaha 115 HP 2 stroke running slow/out of the water

Hi, I am having issues with my new bennington 2010 RC2550. I have a yamaha 115 4 stroke. After running for awhile the engine begins to bog down after a few seconds it comes back to full power. The intervals become closer and closer until eventually the engine stalls. I checked the fule ball and there is no fuel getting to the engine. I have dual fuel tanks. I only have 22 hours on the motor. I had the same issue last year and was told the anit siphon valves had an issue. Any suggestions what this could be? Getting stuck in the middle of a 20,000 acre lake is not fun.

 

[SalmonSlayerr]

Re: Yamaha 115 HP 2 stroke running slow/out of the water

Hello I also have similar probelms. Yesterday I took the boat out and after I lunched her and warmed her up for about 3 mins i left the dock and headed out gradually bringing her up to full throttle. we cruised at full throttle about 30 seconds and she just rapidly slowed t almost a complete stop. the motor did not die but at full open throttle the boat would only go about 10 mph if that. the rpms were around 2000. does anyone know what could cause this? fuel filter? water in gas? sucking air in to fuel line? It was not back firing and idled fine.

 

[saltwaterlife]

Re: Yamaha 115 HP 2 stroke running slow/out of the water

UPDATE. Here what i did after searching for so many days in the repair manual.
i replace the fuel and water seperator, installed new spark plug, clean gas filter at the engine and E VOILA now the engine is back to normal top speed 42 MPH. only needed some TLC i guess. Lesson learn change spark plug and fuel/water filter frequently, such a small cost. Took the boat out to the lake before going to open water (Gulf Of Mexico) and my smile came back. Hope my misfortune will help others.

Hi all, I have a Yamaha 115 HP 2 stroke that use to get 40 MPH now barely 15 MPH. Engine start good. When i engage, the Prop turn normal but not able to go over 15MPH on the water? do you think I need a new lower end? I have only 110 hours!!! could it be possible? The engine sound a bit different too.
Out of the water..