Four stroke 115 vibrates and VERY slow to plane

[Jediropemaster]

I just purchased a 2004 Seapro 190 Bay Boat with a Yamaha 115 fourstroke. When I throttle up it bogs down, vibrates, and takes a long time to get up on plane. I have to put weight in the front to get there. WOT is 3800 to 4000 rpms. I have read online that WOT should be 5000 to 6000. I just pulled the prop and it is a SS Stiletto Y1317.

Any ideas?

[99yam40]

You have a motor problem, fix it before you trash the motor by running it that way

[CatCam]

It could be many things. How is the idle?

Could be a Clogged injector? What you could do to see what cylinder is not working, try disconnecting one spark plug wire at a time to see what cylinder is giving you the trouble....Do this until you find one that does not change the problem. Then you have narrowed it down a bit. Try a new plug on that cylinder....if thaat doesn't do it it is probably the injector.

Your prop size seems about right.

MAKE SURE YOUR FUEL SYSTEM IS WORKING PROPERLY! TANK VENT, PRIMER BULB, ETC.

[Jediropemaster]

The idle is fine. It cranks easily and runs smooth once on a plane. I noticed that the priming bulb doesn't seem to get firm.