TRX300 Leaking carb PROBLEM and Resolution

[Pilgrim 37]

I’m writing this in hopes it helps someone else someday with a most frustrating experience I have had. It’s a bit lengthy but wanted to share ALL my frustrations.

BACKGROUND:

My 1994 TRX300 that is only used once a year for month of November for deer hunting in Maine developed an out of control unstoppable slow fuel leak from drain hose at bottom of carb when I took it out of the shed to get ready for upcoming season.

 

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First thing I did  was remove bowl drain screw to make sure it was clean. it appeared a bit discolored so I gently polished the tip with very fine steel wool.

This did not help.  LEAK REMAINED.

 

Next I tuned in to the chat room here and got several good ideas…….tried cleaning the seat in drain screw with Q-tip and toothpaste; LEAK REMAINEDJ.

 

Chatters led me to go investigate float and needle valve that regulates fuel into bowl so I removed the carb from machine and removed the bowl. Carb was spotless inside. Had to determine if float and or needle valve was the problem.  I rested the bowl in my vice and poured fuel into bowl; no fuel leaked out the drain hose so I knew the drain screw was NOT the source of the leak.

 

As the chatters suggested I directed my efforts now to the float and needle valve. The float appeared clean and it had no leak in it whatsoever. It has to be the needle valve not sealing correctly so I replaced the needle valve with a 5 year old needle valve that had never been used,  Reassembled the carb put it back on engine….LEAK REMAINED!

 

Removed the carb once again, removed the bowl, removed the needle valve. Now I cleaned the needle valve  brass seat with toothpaste and Q-tip as it looked a bit corroded. Reassembled carb and installed on engine LEAK REMAINED.

 

Figured at this point the needle valve I used was bad so I ordered a shinty carb kit to get a brand new needle valve.  Still waiting for kit to arrive as I write this now.

I removed the carb from engine once again while waiting for carb kit; this is most frustrating at this point.  Removed the float and needle again.  I know the float is good so the problem has to be related to the needle valve  and seat so I got a magnifying glass and small flashlight to get a real good look at seat. The bottom of the seat was real clean from the Q-tip and toothpaste cleaning but I noticed the walls of the seat were still tarnished so I wrapped a vey very small piece of fine steel wool around the stick of the Q-tip and removed the tarnish ever so gently. I inserted the needle valve in seat without the float to see if it moved freely now that walls of seat were cleaned.  To my surprise The needle valve didn’t move very smooth. Using the magnifying glass and flashlight on the needle valve I noticed small amount of corrosion on the 4 ribs of the needle valve that come in contact with walls of seat so I removed the corrosion with the fine steel wool and the needle valve then slid in and out of the seat with ease.

Reassembled the carb put in back on engine opened petcock…………………..NO LEAK WHATSOEVER PROBLEM SOLVED.

 

Thank you chatters for guiding me through this most frustrating problem. So glad I did not throw the towel in and by an OEM carb for mucho dinero.

 

[Fishfiles 20,145]

Pilgrim > Glad you got that leak stopped !!!
 

A few things that we might add for future leakers :

 

You can put that Q-Tip swab with tooth paste in a drill and make short work of  the buffing of that brass needle valve seat

 

I think most overflow leaks are cause by contamination from the fuel tank , all it takes to cause a leak is a piece of  rust particle , a piece of  crystalized ethanol gas , algae or dirt  >> many people clean the carb and don't clean the tank and just recontaminate what they just cleaned 

 

If you are having over flow leak problems , I suggest adding a screen fuel filter before the carb 

 

I put a shot glass of Sea Foam in every tank of non-ethanol gas -----  if you can , stay away from ethanol gas ---- if you are burning fuel fast , you can get by with the ethanol , but if it is going to stay on the tanlk any length of time , you are asking for trouble 

 

 

[Pilgrim 37]

Fish this is good advice on the screen filter and sea foam.  Wish I thought of the Q tip in drill trick  that would have buffed out the seat walls in no time. I was initially focused on bottom of seat where the rubber tip meets the brass opening.  i've not had any trouble with this carb for last 15 years that i've owen it.  Hopefully this issue doesn't raise its head for a long time.  By then i'll be to old to remember how to fix it.   God Bless this forum.  wouldn't know where else to get help.  None of the shops here will work on anything older than 10 years and they charge $108/hr!!

[Fishfiles 20,145]

28 minutes ago, Pilgrim said:

Fish this is good advice on the screen filter and sea foam.  Wish I thought of the Q tip in drill trick  that would have buffed out the seat walls in no time. I was initially focused on bottom of seat where the rubber tip meets the brass opening.  i've not had any trouble with this carb for last 15 years that i've owen it.  Hopefully this issue doesn't raise its head for a long time.  By then i'll be to old to remember how to fix it.   God Bless this forum.  wouldn't know where else to get help.  None of the shops here will work on anything older than 10 years and they charge $108/hr!!

$108 is cheap , lol.   Honda of Slidell charges $160 per hour and they won’t work on anything older than 10 years either.  
 

Here is another note ^^^^^^.    Even though it can be a pain in the butt.  I try to shut off the peacock when it is going to be parked for extended time.  Sometimes that over flowing gas finds its way into the cylinder. Leaks by the rings and dilutes the oil in the crankcase as well as make for a thinned oil start up on the rings.  
 

Remember you are only as old as you let yourself be.  
 

One of my favorite stories to tell. The Johova Witness people use to stop by. I always was nice to them even though I Dont agree with their philosophy.  I invite them to the patio and have a drink So the lady looks around the yard and says “ it looks like you like to ride 4 wheelers.  She says , can I ask how old are. How many more weekends can you still ride and are you preparing for when you can no longer do it. “”.  Well I been partying like it is 1999 ever since. 

 

Don't forget the Sea Foam 

 

[jeepwm69 7,611]

Thanks for the write up.  I've always looked at the seat and the tip of the needle.  Never thought about the thing hanging up on the walls of the seat!

[spock 42]

When ever I'm dealing with a leaking carb issue, I like to bench test it before installing it back on the bike/quad. If you can mount it in a vice, then fill the carb with fuel using a clear fuel line. You can observe the fuel in the line & see if it drops while sitting - quite often it takes a while when the leak is slow. Beats putting it on & off the machine when the leak persists!