I've got a Yamaha 250 ox66. 2003. I have so far spent over 1000 or more on trying to have 1 particular issue fixed. When motor is at idle either just starting and not giving much gas or idling in somewhere and not giving much gas. It will spotter and stop and it won't start again. like it's out of gas. yesterday Saturday happened again I checked the bulb on gas line this time it was soft. I pumped it until it was full and still didn't start but 20 min later did. other times I did not check bulb. so far place said loose wores and wing nuts on battery loose. not the fix. next time ignition switch and they say kill switch wires cut. not the fix. last year I had electronic fuel injection replaced I don't know if that was related maybe so but not the problem. I can't keep spending money on random things that don't fix the problem.


Please any advice. thanks a bunch

I can check it out for you

Check with Wild Bill's in Oklahoma

Years ago I had a 2002 model 066 200. It developed a weird issue and would just die and after trying a few times it would crank again and run just fine. Took it in several times and always with no problem found. I started trying to trouble shoot it myself as it started happening more and more and seemed that it was taking longer and longer to get it to crank again. I took a meter with me and started watching voltage on certain parts. I discovered my problem when I started watching the power to the Injectors. I also discovered that the same feed for the injectors also provided power for the High pressure fuel pump. I traced that back to a relay or regulator (honestly it has been so long ago that I cannot ID the part but tracing that power wire back to it should point it out) before I ordered the part I decided to test this theory and ran a wire straight from the positive post up to the wired that fed everything and was able to crank and run without any issues. Once I knew I had my problem found I ordered that Relay or Regulator and replaced it and never had the issue again.

I hope this helps. Seems that the power wire for all injectors and the High Pressure Fuel pump was Yellow with a brown stripe. I could be wrong about that as I am working purely off memory from around 2006 or so.


Jody Kea

Won't fix your problem but if using wing nuts on batteries replace them with hex nuts.

makes sense

Had a few of the OX66 EFI do simular thing, Ended up changing out the EFI relay and fixed all of them , Here is the part # RELAY ASSY
65L-81950-00-00 ,,,,,,,,,,,,,,Very easy to swap , You can do it yourself 1 screw and a wire connector . If your looking at the parts breakdown
it's on #3 electronics # 34

Good luck