I'm posting here for best traffic and also this could be encountered with any carbed vehicle. If mods feel the need to move it that's cool
Machine is an '04 Arctic Cat 400 4X4
Carb was all gunked up with old gelled fuel, etc, etc.
Ran the carb thru the ultrasonic, checked every jet and orifice out. Used a q-tip to clean the seat for the needle. It's clean.
Float is set according to Factory Service Manual- Just touching the tip of the spring loaded plunger on the needle. Yes, I'm quite certain it's properly set, I've verified it multiple times, trust me.
I cannot for the life of me get this needle to seal up. I have never had this issue before and I've been wrenching a long time.
I can attach a hose to the carb, turn the carb upside down and blow thru the hose and the needle will seal. Unfortunately that's not the position the carb operates in.
I set up a bowl of water and I sink the carb into the water until the needle seats and I also check the float height at the point the needle first seats. Gently blow thru the hose and I get air bubbles.
Sink the carb deeper into the water to the bottom of the carb throat, my attempt at trying to induce as much pressure on the spring loaded plunger as possible to seal the needle. Still get air bubbles.
I'm thinking that the crappy fuel sitting in the carb for an extended time damaged the seat by corrosion. The machine has sat for an extended period, over a year. Very hard to get a good close look at the seat area, even using a magnifer headband.
Have any of you guys tried "dressing up" the seat of a carb needle? Used to have a neighbor who would "touch up" the seat lightly with a sharp drill bit.
Seems like it might solve the problem, but I've never tried it.
A new carb is $400. No, I will not try one of the cheap Chinesium carbs off of ebay. Used carbs on the 'bay run 125 and up.
I would like to salvage this carb for the owner. Give me some ideas over and above basic carb cleaning..........
ETA-Rubber tipped needle