Looking for help with a Yamaha 115 4 stroke

[blsmith]

I have a 115 4 stroke, has been a great motor and has historically runr perfect until a couple of weeks back. When in the water it will not make over 2500 rpm. On the hose it will make 5500 rpm with a light skip. I started with plug replacement, no good. Next went to fuel, all filters clean, but I replaced all of them anyway including the vst filter. Still same issue. I cleaned and checked the injectors, same problem, today bought one new injector and tried it in each cylinder, same problem. Swapped out each coil with a new one,guess what, same problem. Does anyone have any suggestions???

[karn1k]

low rpm on 2003 115hp

I found a web site that talked about this problem. There is a filter in the input to the machanical fuel pump that can get pluged. I am told a new part is not avabile from Yamaha so getting it out without dammaging it may be a problem. One person used a screw driven in it to remove it and then just throwing it away.I haven't got back to my houseboat to try this fix out so I am not makeing any promesses. You have to remove the cover to the fuel pump to get to this filter. In one place it sez low pressure pump and another it sez high pressure pump.
GAry
http://www.yamahaoutboardparts.com/f...p-th10974.html

[blsmith]

Thanks for the info. Do you know if that is the High pressure fuel pump on the back of the motor? I changed the VST filter(it is electrical.)

[karn1k]

low pressure pump

I think the pump on the back of the engine is the low pressure pump.
Gary

[blsmith]

the rear pump is as you said low pressure---no filters anywhere on or in it. my motor is a 2006 four stroke and does not have a fuel pump like the one you referenced.
thanks for the help.

[blsmith]

Found the problem

Hey guys, I think I found it. The order of my corrections, which I replaced the plugs first and then did all the fuel work allowed the number one plug to be dry fouled by the time I finished with the injectors. I now think that the number 1 injector was glogged and after I I replaced it , I should have checked the plugs again. I finally did that Saturday morning and have been on the river ever since!!!

I can't thank everybody for the help enough!