Throttle position sensor

[Ricostreet]

I have read and understand the procedure for adjusting the sensor but can anyone tell me how it gets out of adjustment?

[Hamfisted]

Inexperienced people messing with it? The screws have a yellow "dork" paint on them from the factory to indicate if anybody has "dorked" with the sensor and disturbed the paint markings. Do you have a service manual for your motor?


Mike

[Ricostreet]

Mike, I do have a manual and have read the test procedure but I don't have the harness to check it. How important is it--can I just probe the wires with the meter? I'm not sure it's my problem but it has been suggested that it may be causing an irratic idle.
After reading the test steps the first question in my mind was how could it be out of adjustment.???? It has never been moved based on the paint you refered to. I can understand if it's bad and needs to be replaced but -are there moving parts or does something wear out? I didn't want to touch it and become one of the "Dorks" you refer to. I really would like to understand what I'm dealing with.

[Hamfisted]

Rico, yes if you have a service manual and you're comfortable playing with it you can just probe the pink and the orange wire or rig up a feed from the plug so you don't have to puncture anything. The measurement is taken with the throttle idle screw backed off. Only mess with the adjustment if the voltage reading is off. If you're working on an HPDI, they idle rough anyway. Yamaha kills a couple of cylinders on the HPDIs in neutral. I didn't mean you were dorking with it. The only Yamaha I've ever seen idle smooth was a 4-stroke.


Mike

[Ricostreet]

Thanks Mike, Appreciate your help. This is a '98 OX66 225 with a phase two installed--carbon reeds and modified cages.

[aquadj]

I spent countless hours trying to adjust the correct voltage for the TPS on a 98 OX66 250hp. I was able to get readings by probing the wires but the adjustments would always change each time I ran the boat. I finally bought a new sensor and realized when I removed the old one, the armature behind the sensor was gummed up and wouldn't allow for a consistent reading. Since i changed it, it's running good. Are the RPMs changing at all speeds or between certain ranges? Dave

[Ricostreet]

When I start the engine cold it will idle at around 1000 +-, after a short warm up it will drop to 700 +-, mid range and top end have not been a problem so far but when I come off of plane, it will drop to 400 and try to stall then pick up again and surge between 400 and 1000. When I start up again it will go through the same scenario. I have not adjusted the tps but I have tried the idle screw and either get too much or not enough. So far, no problem other than at idle speed. Maybe I should be happy?!!!
Were you having a problem at mid-range and top end too??

[aquadj]

My problem was only at mid range between 2400-3600 RPMs and not consistently.