250 TPS Adjustment?

[Salty Dog]

Tomorrow I need to change the TP sensor on my 93 250 Yammie and have no idea how to adjust it. Any help would be appreciated.

[boats.net]

Your best bet is to get yourself a service manual the carbs need to be sycronized before adjusting TPS and carb linkage on that engine is a little complex. But the TPS adjustment is simple: back off idle speed setting screw to allow throttle plates to close completly, connect voltmeter positive lead to pink wire and neg lead to orange wire( you will have probe TPS wire connector can use a paper clip to probe into connector)turn ignition key on and loosen 2 screws holding TPS to bracket and adjust TPS to obtain .51 volts tighten TPS and open and close throttle plates several times and recheck voltage.

[Salty Dog]

Thank You!!

[Salty Dog]

One more question please. My manual says to adjust the idle screws on the top left of the carbs 5/8" out. They were all out at least one turn and now it idles like crap.

[Salty Dog]

One more question please. My manual says to adjust the idle screws on the top left of the carbs 5/8" out. They were all out at least one turn and now it idles like crap.

[Salty Dog]

With the TPS connected it reads from 3.7 to 4.9 volts closed to open throttle. I reinstalled it 5 times flipping the plastic connector around each time. The local Yamaha dealer won't touch anything older than 95 so I'm on my own.

[boats.net]

The pilot screw setting is 5/8 plus or minus 1/4 turn, I usually set to 3/4 turn. Are you sure you are using the pink and orange wire on TPS voltage. The orange and red wire is the input voltage to TPS and 3.7 to 4.9 would be ok between orange and red. The pink and orange are the output wires the voltage should increase when open throttle on carbs by hand, if no voltage increase then TPS is bad.

[Salty Dog]

Thanks for the reply. I think there are only 3 wires, orange pink and black. I'll look tomorrow when It gets light out.

[Salty Dog]

The sensor has red, pink and orange and the motor has black, pink and orange. I was getting the 3.7 to 4.9 from the pink and orange wires. Should I try a different set of wires? Thanks.

[Salty Dog]

bump

[boats.net]

Yes, open throttle and watch voltage it should increase in voltage when throttle as the opens if not then try the other wires.

[Salty Dog]

OK, I just set the TPS and it still won't hold and idle. WHen I unplug the TPS it idles but not great. Anymore help is greatly appreciated.

Thanks,
Ron

[Hamfisted]

The manual enrichment valve is closed right? Did you try just turning up the idle screw? You said you had new sparkplugs right?


Mike

[Salty Dog]

Yes,no and yes. If I adjust the idle screw do I have to reset the TPS. I set it with the idle screw turned in 1.5 times. Also had a mechanic tell me this engine has a primitive computer and gives trouble codes. Is that true?

[boats.net]

Adjust TPS with throttle plates completely closed after adjusting then adjust idle screw to set idle rpm to 700 rpm's. Do not make any more adjustment's to TPS.