[Username954]

Hey everyone im new here and was recommended to come here for the best help . And No one else can figure it out .I fixed many atvs but this one has me stumped . It's a 2005 Honda 350 TRX fm rancher 4x4 . The problem is when it starts up it won't stay on long and when i give it gas it dies it's not accelerate at all instead it just completely dies instantly each and every time I try to give it gas. So initially I thought it was a carb issue .so I cleaned/rebuilt it to perfection and no difference . So finally I replaced the carb with a brand new carb in addition I flushed gas tank and added fresh gas ,new ngk spark plug , new uni air filter ,fresh castrol oil and oil filter . And still it will not run correct . It will start right up and idle briefly then died or when i press the throttle it dies immediately . Can anyone help please .thanks .

 

[shadetree]

remove the carb, put the old carb back on, trash that china carb..its junk !!. have you checked to see if you have a air leak around or at the intake carb boot ?. are you sure your getting plenty of fuel to the carb ?. is the fuel tank venting right ?. have you checked the top of the carb for a tear in the diaphragm that sits on the very top under the cap ?. is it attached correctly ?. checked the timing ?. checked the compression ?.

 

[shadetree]

oh, and please put this thread in the repair section, this section is for intro only, not the history of your atv..lol.

 

[shadetree]

i'll move this thread .

 

[Username954]

Thanks for fast response shadetree

The old carb was previously tampered before I got it and seen better days it's not oem. I put the new carb on .And still same problem .I don't know if the tank it vented but gas if flowing perfect from gas line coming from tank .the carb has a vent line does that connect anywhere ?I didn't check compression and didn't check timing I'll have to check those

 

[Username954]

And yes I checked air leak by spraying carb cleaner and no response .it almost seems like it's not geting gas to the engine from carb .

 

[Goober]

The old carb was previously tampered before I got it and seen better days it's not oem. I put the new carb on .And still same problem .I don't know if the tank it vented but gas if flowing perfect from gas line coming from tank .the carb has a vent line does that connect anywhere ?I didn't check compression and didn't check timing I'll have to check those

Actually very good to know the carbs are both suspect.
Download the service manual and check out the parts link in my sig block. You can verify which carb you should have and then visually inspect your carbs to see if they are genuine oem.
I had two shop rigs with constant drive ability probs—wrong carbs—i bought two new carbs and they run great now. So i think if you have aftermarket carbs, the choke and throttle cables don’t fit right and you simply can’t get reliable rebuild kits for them

 

[LedFTed]

how is the flow from the gas tank. disconnect hose from the carburetor an check flow. maybe your not getting enough gas to the carb. seems i remember a problem with the vent cap, not working properly, or shut off valve, also.

 

[Username954]

The quad was running great a few months ago with a aftermarket carb . And the carb I just bought is oem standered for my model 05 Honda TRX fm rancher 4x4. Here's the carb I just installed. Also I pulled the gas line from carb and it has a nice flow goung to carb .I removed gas cap no difference with cap on or off . I have to check compression , valves ,and timing today (shadetree)?

 

[shadetree]

The quad was running great a few months ago with a aftermarket carb . And the carb I just bought is oem standered for my model 05 Honda TRX fm rancher 4x4. Here's the carb I just installed. Also I pulled the gas line from carb and it has a nice flow goung to carb .I removed gas cap no difference with cap on or off . I have to check compression , valves ,and timing today (shadetree)?

thats a china after market piece of junk !..lol.

 

[wheeler]

Ya when dealing with carbs I ALWAYS stick with OEM...

I agree with everyone else, make sure you have flow to the carb, take the original OEM carb & go over it again! You very well could have missed some small spec of dirt even though u "think" it was perfect like you say. You say you couldn't give it any throttle at all or it would die & wouldn't run long or die.. I would check your float & needle valve. I've had a throttle cable get pinched before giving me issues so maybe check that as well...

 

[Username954]

Thank you guys so much for all the info .I'll be back in town in few days and I'll go over everything you guys said and let everyone know what I find out .

 

[Username954]

Hey everyone .got back today . And did a compression check and I got a reading of barely a 100 PSI .LOW ! AND YES I had throttle wide open. So what should I check first valves and piston rings ?

 

[Username954]

Also i borrowed my buddies OEM carburetor he has the exact same ATV his is running perfect . I put his carburetor on my bike and it acted the same exact way as the aftermarket brand new carburetor that I just bought . It will start up in idle briefly and turn off and it will not let me accelerate the throttle or it turns off instantly

 

[shadetree]

time for a top end repair. this means pulling cylinder, spec'ing it, and see where you can go from there ?. if its been bored over too many times ?, you will need a new cylinder to start fresh with. if the cylinder is not over spec's of service limits ?, then you can bore it out ( over ) another time, start with a new piston kit. while you have the top end down, this is the time to inspect the crank rod for any top play at wrist pin, and play at bottom end of rod. if either one has ANY play ?, then the rod MUST be replaced !!!. or you will just throwing time and money away.