Hi Guys,

I have been having a fun time trying to diagnose this one. First let me describe the issue.

Problem : After running the ATV for a while (10-20 minutes) it will die when I let off the throttle. Everything goes dark. The console shuts off, lights, ect. If I let it sit for a minute or so and turn the key again the power returns. If I try it immediately the console does not turn on.

Things I have changed/checked:

- I removed the cable to the thermistor and the fan runs constantly and the speedo blinks and warns me of high temperature. This leads me to believe the unit is not overheating.
- Fan does work if I apply 12 volts to it.
- solenoid and starter are both good.
- kill switch is off
- good gas

Second Problem :

- Is there a better way to bleed the foot brake. No matter what I do can't get it to bleed properly. Does the master cylinder go bad often ?

To bleed I opened the res and poured in some fluid. I pumped the foot brake about 15 times to get all air out of the res. I capped the res and had someone push on the foot brake. I opened the bleeder valve and then closed. Then I had them release the brake. I did this a few times.

Thanks for your help in advance...

 

Slice the pouch open on the sealed thermal circuit breaker located up from the battery. If it's corroded,it can over heat and cut off power. Then when it cools down it can work for awhile. You can get these 20 amp breakers at any auto store if needed. If the circuit breaker is ok,then it could be an ecm module over heating causing problems. Item #2 and 28. Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
You can use a Mityvac brake bleeder on the rear caliper to see if it helps on bleeding while you pump the brake pedal. The small rear m/cylinders are a pain to bleed at times,plus they do have a habit of leaking air at the seal if the brake pedal isn't used every now and then. Not cheap on these small master cylinders if it needs replacement. Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

Thank you very much.

Is there any way to test the ECM ? How often does this occur in your experience ?

Can I just install any 20 amp breaker ? Not sure how to troubleshoot this without destroying the pack ? Can I just install an inline fuse and ride for a bit ?

Man this is an pain... While troubleshooting this one the starter went bad. WOW was it a project to get that out. All set on that project though.

Thanks again

 

Don't use an inline fuse. This breaker kicks off and on if there is a problem.Very easy to replace if needed. Just check that you have power to each side of the red wires leading in and out of the pouch,BUT if terminals are corroded,may show good until it heats up and trips. Just slice open the pouch. Ecm mainly controls the charging to the battery and power to the fan,but can short out causing problems also.Really no test on it,just check that the battery is charging 14-14.5 volts while running. Fan also uses a thermistor sensor in the oil cooler that goes to the thermistor module under the front panel,but both these rely on the ecm also. Best to have a manual that you can look over that shows help on repairs,trouble shooting and maintenance.Here's cheap one.2004 Polaris Magnum 330 Service Manual PDF Download
Plus here's what the circuit breaker looks like.