Throttle Position Sensor could be bad?

ITBeachbum

Cadet
Joined
Aug 17, 2008
Messages
7
Hey Guys. First and foremost I wish to commend everyone on this site. I have gained a wealth of information and saved hundreds of dollars. For that I thank you.. ( Tipping of Hat).

I've been toying with my 2001 Yami ox66 250 for a while now and trying to understand why I can't reach over 5000 RPM, I understand WOT should be around around 5500. My first thought was the prop, so I called Edgewater and asked a silly question. "What should the proper prop be on a 2001 225 CC with a Yami 250. The response was a 19 pitch. or 19M which is stamped on the hub. The diameter I think is 17, but I'm not 100% sure. So the prop appears to check out. I remember someone having a similar boat and setup, only he was able to reach 5600, and 48 MPH. NICE!!!!!

Anyway, after going through the service manual about 4 times, and the SELEC service manual I decided to look closer at the TPS. I followed the steps by first disconnecting the linkage on the #1 throttle body, and check the voltage between the orange and pink wires. The voltage was reading low so I made the adjustment to read .5 volts. (spec .5 - 5 volts). Only my DVM at WOT was reading 4 volts. So could this sensor being going bad bacause of the voltage drop of one full volt, and could this be the reason why I can't reach top RPM? The sensor is not cheap so I need to exercise caution when replacing expensive parts.

In addition, I have adjusted the oil link to spec. Cleaned the O2 sensor, cleaned the VST filter, fuel filter, water sep filter, and replaced the plugs. Of course all of this items were addressed throughout the summer. The only other three items I'm have not ruled out are the pumps, replacing the O2, and TPS sensor. Also cleaned the fuel injecters filters. but they looked fine.

Commpresson check fine...

She runs fine, and even better once I adjusted the oil link and TPS. As before she would run rough and hesitate a little out of the hole. So I may be onto something with this tps sensor I believe.

Any ideas?

James

Stuart, FL
 

TimC2520

Cadet
Joined
Mar 16, 2008
Messages
21
Re: Throttle Position Sensor could be bad?

Personally, I would not worry about it. Doesn't the manual say max rpm's in a range of 4500-5500? I understand closer to the high end would be better which you are at.
I have never been able to reach the top at 5500 but can get to 5300 and that is early in the season, April/March. By Aug/Sept/Oct, getting to 5K is difficult, but if it's running great, why mess with it? :confused:
 
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