The sensor is used by the computer to control the fuel injection system
according to the amount of air being fed into the motor. The o2 sensor
closes the loop in terms of lean or rich by small amounts but the TPS is
where it starts. Given a set throttle position there is a certain amount of
air flowing thru the intake and therefore there is a certain amount of fuel
needed to create the correct combustion.

As for the warrenty - should be covered as long as any of the electronics
are covered. If this sensor is not set right - you stand a chance of
running the engine lean and burning it up. I think they had rather adjust
the sensor than replace the engine. I would get a shop manual for this
engine and find out how to adjust. It is usually a certain resistance or
voltage at fully closed and/or fully open.

As for the trash - definetly get a water seperator filter installed if you
don't have one already. And replace the existing fuel filter. If trash is
getting into the fuel pump it is coming from the tank and you want to keep
it out of everything. Water seperator filter will do the trick. And by the
way - trash in the engine is not covered by warrenty so if the engine goes
down and they find trash in the fuel pump - they may not warrenty it
depending on the dealer and how much he likes you.

--
Tony
my boats and cars at http://t.thomas.home.mchsi.com

wrote in message
oups.com...
I have a 1 year old 250 DT (two stroke). It started running rough just
before the 20 HR check up. The dealer adjusted the Throttle Position
Sensor (or throttle position valve)at that time and the engine ran
great for the next 50 hours.

The engine began to die at low (750 - 1000) RPM and would not start
untill the gas "bulb" was pumped up again.

At the 100 check the dealer found "debris" in the high pressure fuel
pump. However, they did not replace the fuel filter ? They also
adjusted the Throttle Position Sensor again. It runs smoothly at my
house. I have not had chance for all day fishig trip to test it.

My question, is anyone out there familiar to TPS (or throttle valve
sensor). The dealer claims it can be "adjusted" but only by the dealer.
In addition, they say that this is covered by warranty for only 30 days
after purchase ?

Any advise will be appreciated.

SpeckTater