F115 tps

[Yarblexed]

Hello,

I have a new to us 2005 F115 that is not getting enough RPM's. WOT we would spin around 4500. We were told that is to far down to be simply over propped so we started looking for other issues. All the cylinders seem to be operating correctly and the computer is not throwing any codes.

The computer shows that the throttle is only opening to 80 degrees with the control full forward. An inspection quickly found that the throttle linkage was not set up correctly as the throttle roller was not reaching the flats of the throttle cam. We went through the adjustment procedure and found the major issue was up front with the remote limit adjustment. So now we have the linkage adjusted to exactly as stated in the service manual.

The linkage is doing what it's suppose to be doing and at fully closed throttle we are seeing .733 / 0 degrees on the computer. However, at WOT (verified by eyeball) the computer is only showing 83 degrees of throttle, unfortunately I did not record the indicated voltage.

My question is, how important is the WOT indication? I can't find any reference to it in the service manual as it continually refers to the .733 setting. Does / should the computer see 90 degrees when the throttle body is open to 90 degrees? If so, is there away to calibrate / adjust this or do I have a bad TPS?

Thanks in advance,
Shane

[Inducted]

Those readings are probably correct for WOT. Do more research on your prop size. Maybe the boat was never rigged properly. How is your engine at idle? do you have proper rpms at idle? I'm thinking a bad tps would show up at idle, that engine has a very involved throttle valve and linkage setup. just a thought.

[Yarblexed]

Inducted, I suspect your right and the motor is a bit over propped; it’s a flats boat so it’s likely the first owner wanted it to “jump” out of the water.

That being said we have not had it in the water since we found the throttle linkage set wrong. At WOT the roller was still down on the cam and not in the asterisks depicted in the shop manual. After performing the setting procedure in the manual the throttle roller is on the “asterisks” or flat portion of the cam now at WOT, and where the computer was reporting 80 degrees it now reports 84 degrees.

I’m just stuck on thinking that if the butterflies are open to 90 degrees the computer should know that. Maybe I am making a mountain out of a molehill.

[boats.net]

Rarely ever see one go to 90% at wide open throttle, as long as throttle bodys are in sync and TPS is at 0.732(0.718-0.746 within specs) it is ok.