1998 Yamaha 250 OX66 Cuts Out

[jwbergeron]

My starboard motor cuts out intermittently. When the motor runs, it runs fine....but once in a while it will cut out like a key is turned off, eventually it will start again. When it cuts out, the high pressure fuel pump doesn't run at the turn of the key. But if I let it sit, eventually I'll turn the key, hear it run, and it will start right up. I've swapped complete vsts from one motor to the other and continue to have the same problem, so I'm pretty sure the fuel pump is fine...somewhere along the line, somethings not telling the fuel system to run.

I would greatly appreciate any thoughts or suggestions anyone might have to help troubleshoot this thing. Thanks guys

 

[rodbolt]

Re: 1998 Yamaha 250 OX66 Cuts Out

ok
on that motor the pump is controlled via the ECU.
the red/yellow pump wire is 12V+ anytime the key is on.
the blue is controlled at low speed via the ECU and the resistor, above about 1600 RPM the blue(ground path) is controled by the ECU.
now ya gotta find which one is failing.
a clogged VST filter will give you the same indications as will a bad lift pump.

 

[jwbergeron]

Re: 1998 Yamaha 250 OX66 Cuts Out

Thanks Rodbolt. The VST is clean as a whistle. Lift pumps all replaced last fall. Now I've got to wait for it to fail again...

 

[jwbergeron]

Re: 1998 Yamaha 250 OX66 Cuts Out

Pretty sure I found the problem...power side. Its the relay...I happened to tap it and notice I got voltage back. I pulled it loose and any time the motor cut out a couple taps on the relay would bring it back (and visa versa). The part is on order (200 big ones), so I'll follow up if anything different.

Many thanks Rodbolt (as always).

 

[rodbolt]

Re: 1998 Yamaha 250 OX66 Cuts Out

if you can tap the relay and make it work or quit you may have found your problem.
any yellow/red lead on your engine should be 12V+ at key on.

 

[cousinabe]

Re: 1998 Yamaha 250 OX66 Cuts Out

just curious,
is it part# 65L-81950-01-00 inside the electrical cover area?

thanks.

 

[jwbergeron]

Re: 1998 Yamaha 250 OX66 Cuts Out

yes...top left corner under the cover as you face it. Trace the red/yellow wires to it. One screw holds it on.