I used a pressure sprayer to clean the mud off of both AC 400s. Both started right away after cleaning the mud. While warming one of them up at idle, the RPMs started to smoothly rise by it's self and then quit running. It is full of gas, the starter turns the engine over, all the fuses are good, even the 30 amp fuse that is under the right rear fender well. Has this happend to anyone else? Maybe someone can give me a place to start to fault isolate this problem?

Thanks
Bajacat

 

your not giving us much to go on. do you have spark at the plug? is there water in the air box?

 

The air box is dry. No spark.
We were riding in mud and snow, no deep water crossings. I think I must have some type of water intrusion when I was pressure washing the mud off the quads. The funny thing is that, it started, ran great while warming up with the choke off, then the RPM's starting to go up and then it shut down.
Hopefully I can fix it at home and not bring it to the shop. My shop manual is at my place in Baja and I will not be able to get it until May. I hate to pay the dealer to fix it.
Thanks for answering my post.
Bajacat

 

Bajacat,

The only thing I can think of that would cause the RPM's to rise would be to lean out the carb or ahve the timing advance. Since the timing is automatically adjusted by the CDI I would check there for water issues. You might also want to check the coil as this is where the plug wire connects.

You may be able to let it sit in a warm garage for a week or so and dry it out to get it to tun again. If not then the increased RPM's and not running is a result of a short that may have damaged the CDI or coil.

Pressure washers are good for cleaning but if you are not careful where you point the nozzle and have the pressure cranked up it can peel stickers off and force water into places unknown. (like around bearing seals, electrical connects etc)

SJ

 

I wanted to say thanks for the replys. I went out to the garge this morning and it started right up. [img]i/expressions/face-icon-small-happy.gif[/img] Back to using the brush and hot water. [img]i/expressions/face-icon-small-tongue.gif[/img]
It looks like we are heading to the Desert this weekend with two quads! The fun never ends.

Thanks,
Bajacat

 

You may want to look into it more later because I would hate to see you post on here some time in the future that you went through a little bit of water some place and the same thing happens again. Only this time from water spashing.

I use dielectric grease and goop up every connection I can find whenever I can. Usually when I do my yearly oil change, etc. You can find a tube at your local auto parts store for around $5. Well worth the $.

If you pressure wash use low pressure, I turn mine down I think its at 650psi and keep the nozzle in a flat spray not a stream.
Have fun in the desert, I still have too much snow here to do too much riding. (or should I say ice as it is raining a little today)

SJ

 

Check Air box for water.
Check spark plug.
Check for fuel in the gas line.

 

Glad to hear you got it running I would do what swampyjunior said about the dielectric

 

one other thing that i did with my quad is i bought liquid electrical tape and coated all of the connections. i thought about using grease but that can wash out over time.

 

Did you accidently turn the gas off. As an engine gets lean (running out of gas) it will rev up. Once out of gas it will quit.

Dirty air filter
Obstructed gas line - blocked
Dirty carb