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Discussion Starter · #1 ·
Have a 1999 300 4x4 fourtrax and it idles fine. When I give her just a little bit of gas it spudders until I give it 25% throttle or more then it smooths out. This is when I am starting from a dead stop. If I am moving and in third gear or higher, it's smooth sailing.

I have done searches and came up with cleaning the carb, and getting a carb rebuild kit. It doesn't matter what what jets I have in the results are the same. Checked my plug and it looks good, but replaced it any way. I'm at the point of taking her in to the shop and having a mechanic give it a look over, but I was hoping someone might have a suggestion or two I can try before I admit defeat.
 

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start with a carb rebuild kit, it will be a lot cheaper than what a shop is going to charge you !!!..lol. check to make sure your getting plenty of fuel reaching the carb ?. vent on gas cap set to '' on '' ?. petcock under tank clean ?..the bowl under it needs cleaning time to time :). check your air filter, clean ?. oem snorkel have an dirt dobbers nest in it ?. any air leaks from carb to intake around the intake rubber boot ?.
 

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Discussion Starter · #3 ·
Ok time for an up date.

Took apart carb, and dropped it in the parts cleaner, again. Blew out all openings, jets, etc. Tried the card rebuild kit and the stock parts and no change.

Checked snorkel and found dead mouse. Hope that would have fixed it, and nope. Air filter is new.

Adjusted air/fuel screw again and tried running it rich, lean, and just right and it still spudders under light throttle.

Opened up the drain on the bottom of the carb and fuel flows freely through it. Pulled the petcock and looked inside and she is clean and the filter is not obstructed at all. Nothing made it any better, but nothing made it worse either.

It acts like it's not getting enough gas, but when I give it more throttle it smooth and runs good.

Hoping someone can pull a mirical from their magic box of knowledge on this one.
 

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Ok time for an up date.

Took apart carb, and dropped it in the parts cleaner, again. Blew out all openings, jets, etc. Tried the card rebuild kit and the stock parts and no change.

Checked snorkel and found dead mouse. Hope that would have fixed it, and nope. Air filter is new.

Adjusted air/fuel screw again and tried running it rich, lean, and just right and it still spudders under light throttle.

Opened up the drain on the bottom of the carb and fuel flows freely through it. Pulled the petcock and looked inside and she is clean and the filter is not obstructed at all. Nothing made it any better, but nothing made it worse either.

It acts like it's not getting enough gas, but when I give it more throttle it smooth and runs good.

Hoping someone can pull a mirical from their magic box of knowledge on this one.
check the area where the dead mouse was , see if you missed any nest/hay/whatever ?. the oem snorkel must be completely clear !.
 

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Discussion Starter · #6 ·
I really hate to say it, but she is clean. I started with compressed air and nothing else came out. Then I took the hose to it, and still was clear.

I hate to say it, but I think I might be doing the drive of shame.

Wait!!!!!! One last question. I usually keep my tank low because I don't want a lot of gas sitting in the tank for long periods of time. I have the pet cock on reserve and the tank is on the low side. Would it make a difference if I filled the tank up and switched back to the on position?
 

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I really hate to say it, but she is clean. I started with compressed air and nothing else came out. Then I took the hose to it, and still was clear.

I hate to say it, but I think I might be doing the drive of shame.

Wait!!!!!! One last question. I usually keep my tank low because I don't want a lot of gas sitting in the tank for long periods of time. I have the pet cock on reserve and the tank is on the low side. Would it make a difference if I filled the tank up and switched back to the on position?
don't know if it will help ?, but keep it filled, and make sure gas tank cap vent is set to '' on '' ?. and never keep a gas tank low !!!!. reason ?, more chances or moisture building up in the tank. its best to keep the tank full if posb.
 

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My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
 

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Discussion Starter · #11 ·
Those ideas were floating around in the back of my mind, but to be honest I had reached my frustration limit. I had thought about just buying a new carb, cheaper than going to the shop, but decided that if the problem still existed after I put on the new carb I would have gone way past the frustration limit.

Once the shop figures out the problem, assuming they do, I will consider this a paid for learning experience.
 

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Discussion Starter · #12 ·
My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
I really hope it is something as simple as what you experienced. Hopefully won't take 5 hours to diagnose.

No I do not have a servise manual. Where might a guy look to find one?
 

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My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
that tab your speaking of ?, that makes a world of difference on how it runs !. most people don't understand this ?. not sure if I brought that tab to your attention awhile back ?, but yeah, it has to be correct !.
 

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My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
I really hope it is something as simple as what you experienced. Hopefully won't take 5 hours to diagnose.

No I do not have a servise manual. Where might a guy look to find one?
you may be able to down load it from our site here ? :).
 

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Discussion Starter · #15 ·
My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
that tab your speaking of ?, that makes a world of difference on how it runs !. most people don't understand this ?. not sure if I brought that tab to your attention awhile back ?, but yeah, it has to be correct !.
Just for reference, where is this tab? Is this different than fuel/air mixture scre?
 

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My old 1986 350 fourtrax had the little bit of throttle spudder awhile back plus the idle was not real good. Engine would run ok once it got past the spudder.

I could see what appeared to be richness (little soot) in the exhaust when it was spuddering

I removed the carb and give it a good cleaning, no kit and still same.
I removed the carb again, installed a new kit and used a Honda service manual to carefully check all settings and found that the throttle valve synchronization was off on the carb due to some Bubba being in the carb previously making bend adjustments.

Both the new kit and getting the carb throttle valve synced cured the spudder at low throttle.
If that had not cured it I was headed towards, spark plug, timing, valves, etc.

Do you have a service manual for reference?
that tab your speaking of ?, that makes a world of difference on how it runs !. most people don't understand this ?. not sure if I brought that tab to your attention awhile back ?, but yeah, it has to be correct !.
Just for reference, where is this tab? Is this different than fuel/air mixture scre?
nothing to do with the pilot jet needle. this tab is on the right hand side, behind the black plastic cover that is over the throttle cable. these tabs we speak of, one is flat, small. the other is what I call a fork, when this fork gets wide/bent/open ?, it messes up the throttle response so to speak.
 

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Discussion Starter · #17 ·
that tab your speaking of ?, that makes a world of difference on how it runs !. most people don't understand this ?. not sure if I brought that tab to your attention awhile back ?, but yeah, it has to be correct !.
Just for reference, where is this tab? Is this different than fuel/air mixture scre?
nothing to do with the pilot jet needle. this tab is on the right hand side, behind the black plastic cover that is over the throttle cable. these tabs we speak of, one is flat, small. the other is what I call a fork, when this fork gets wide/bent/open ?, it messes up the throttle response so to speak.
Got it. Thanks for the info.
 

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Discussion Starter · #18 ·
Well the Servise Manager called from the Honda shop and said they could find anything wrong outside of the carb, so now he is going to pull the Carb and look for an internal issue. With my luck they probably won't find any issues. Then I will have a bill for two shop hours and nothing to show for it.

How much more effective is boil water with lemon juice and letting the carb soak, instead of using parts cleaner?

At some point in time I might just look into getting a new OEM carb!!!!
 

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Well the Servise Manager called from the Honda shop and said they could find anything wrong outside of the carb, so now he is going to pull the Carb and look for an internal issue. With my luck they probably won't find any issues. Then I will have a bill for two shop hours and nothing to show for it.

How much more effective is boil water with lemon juice and letting the carb soak, instead of using parts cleaner?

At some point in time I might just look into getting a new OEM carb!!!!
if this is an old trx350 ?, you won't be able to buy an oem carb today ?..they are discontinued !. your best bet ?, buy a carb rebuild kit, read my sticky on how to clean a carb in the repair section. how in the world did you get a Honda dealership to work on this ?..most dealerships won't touch anything that is 10 years old or older ?.
 

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Discussion Starter · #20 · (Edited)
It's a 300. I get funny looks from a lot of guys when I go hunting with it. Something about a 300 would be great for their daughter. I have no idea what they are talking about. That little sucker has hauled a ton of hogs, deer, and elk off the hill just fine.

I did a search and it looks like there are a few places that have an OEM Carb still. Think they wanted 250 dollars or so for it. I'll double check to make sure it isn't a China Special.

The Honda shop was more than happy to take her in. I have a feeling I will be forking out two shop hours and it still won't be right. I already tried a rebuild kit, but I will go over your post on how to rebuild a carb.

I'm not sure if you mention it in your post, but boiling some lemon water and soaking the carb in it better than the cleaners available these days. My hope is maybe there is a little gunk in the path way bellow the low speed jet that the parts cleaner couldn't get out.
 
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