Yamaha 150 four stroke stalls

[high sierra]

My first post on this site. I have a 2007 Yamaha 4 stroke that has a stalling problem when throttle is applied. I synch(d) the linkeage and balanced the throttles with my mercury filled vacuum tester. I set the tps at .70 with the engine stopped. When started the engine stalls or stutters badly when throttle is applied. When I start the engine , the tps will have changed to .7 to roughly .735 and varies each time the motor is started. If I set the throttle positiion sensor to .7 with the engine running, idle has changed somewhat and the engine still stutters when you try to raise the rpm. I have disconnected the shift cable and the throttle cable and when advancing the throttle at the motor I still have the same problem. Sometimes it is worse and sometimes not so bad. I have taken sensor readings and the they seem to vary quite a bit. When you try to set the .70 =- 02, the tps sensor has to be moved so little , it is very hard to do. Even tightening the screws changes the reading . So , do I have a bad TPS? Do they all act this way.? I have the factory manuals and and am quite familiar with motors, but this one is giving me trouble . I hate to buy a tps without being very sure of its need. Thanks for any help. high sierra

[high sierra]

Yamaha 150 4 stroke stalls

Anyone with l\knowledge on tps?

[seanfisho]

150 stalling

does it stall all the time or just now and then and when
you do start it does it fast idol first and then drop down
the revs when hot.
sean

[high sierra]

150 stalling

Hi Sean, it starts and runs on fast idle perfectly. When it drops to regular idle, it runs perfectly. Only when you start to bring up the rpm, does it stumble or shut down. I have noticed that the tps sensor reading changes somewhat when you restart. Also wiggling or tapping on the sensor will change the reading a small amount.(.7 to .735 roughly) Jamming the throttle partly forward (most of the time) causes it to catch and explosively accelerate. I took out the sensor and checked it and of course it was clean. When I put it back in, the numbers changed again but were more stable. high sierra

[jiggamurf]

150 stalls

high sierra, did you get your issue resolved? if so what have you found?. im having a similar problem i have a 2006 f150. ive' cleaned injectors (professionally), replaced vst filter, all engine filters, including air filters. boat fuel filters. all seemed to help. on one of my engines the problem went completly away all of a sudden but the other one still has the problem very minimal. im not satisfied because i still dont know what caused it and what fixed it. i have seen this problem very often.

thanks
ric