'97 Yamaha 250 efi loss of power

[heatz]

I have a pair of 250s and just started having a problem with one of them. I can't get above 3600rpm, and all that happens when throttle is advanced is that the fuel flow goes up (way up). I put in a new 02 sensor last year, but this does not surge like the typical o2 sensor problem - it just wont go above 3600. I dont think it can be a filter issue since the fuel flow is way up there (up to 25 gph for 1 engine). All plugs look clean. Any ideas what to check next ?
Thanks,

 

[heatz]

Re: '97 Yamaha 250 efi loss of power

I have a pair of 250s and just started having a problem with one of them. I can't get above 3600rpm, and all that happens when throttle is advanced is that the fuel flow goes up (way up). I put in a new 02 sensor last year, but this does not surge like the typical o2 sensor problem - it just wont go above 3600. I dont think it can be a filter issue since the fuel flow is way up there (up to 25 gph for 1 engine). All plugs look clean. Any ideas what to check next ?
Thanks,

 

[heatz]

Re: '97 Yamaha 250 efi loss of power

this is an 0x66 engine..... mechanic can't come look at it for another week anyone... have any ideas ?
Thanks

 

[rodbolt]

Re: '97 Yamaha 250 efi loss of power

amy yamaha dealer can get you one. but it sounds like a fuel issue and no codes are set for O2 sensor data, that must be tested with an ohm meter and the test harness as per 3 tech bullitens.

 

[heatz]

Re: '97 Yamaha 250 efi loss of power

I swapped the 02 sensor (and tube) from 1 engine to the other and have the same problem with the original motor. could this be a VST issue ? Even if my fuel flow is so high ? Could it be a powerpack going/gone bad ? Please help !!!

 

[bernieb]

Re: '97 Yamaha 250 efi loss of power

Use the "search" all the way down on the bottom and put in "fuel problem"