Hello,
Ive cleaned the carbs half dozen times and correct adjustments put new fuel lines on still have same problem. You have to always choke it to start (when hot) then you feather the throttle to get the rpms up then it will go and goes good but when you let off you have to feather backup to go and wont idle just dies. I did notice that fuel will stop flowing from the tank to the pump when it idles down then dies but it still has gas in the lines. Do you think it needs fuel pump rebuilt. Or am I heading in the wrong direction. 92 polaris indy 440 L/C Any suggestions will be helpful!


Thanks

A plugged pilot jet will cause that symptom. Even though you've cleaned the carbs many times, you'll need to find a parts fiche and figure out where the pilot jet is.

If the fuel pump is failing you'll experience a fuel delivery problem at higher RPM before you see a problem at idle.

The fuel stops flowing at idle because it has no where to go.

I would also do a compression test. I have a 92 polaris sp 500. It would not idle, always had to hold the throttle to start it. Ran ok when rolling. Every time I stopped, it would die. Ended up losing a cylinder the same day. Losing compression.

Its worth a check. If you have a cylinder that is running less than 100lbs compression, theres your problem.

I took the carbs out and cleaned them. They were clean. Checked crank case for leaks by spraying WD40 around seals. It has 110psi on each cylinder. If I set the fuel air at about 1/8 turn it will idle and start good but you still have to feather the rpms up to 2500 to 3000 before it take off

Anymore ideas

Not sure if it has a fuel or air screw (or both) but maybe try one full turn out from lightly seated.

1 screw adjustment besides the idle screw I tried from 2 full turns down to 0 1/8 increments. At 1/8 out it will idle any more it wont idle. But it still bogs and slowly revs up 3000rpms then revs out good.

It sounds like a fuel delivery issue in the 0-1/4 throttle range. If these carbs use an air screw, opening it up more than 1/8 is probably giving it too much air for the amount of fuel being provided. The pilot jet is the only thing that controls fuel delivery, until the throttle is pushed in enough for the needle jet to start providing fuel. Have you identified the pilot jet and ensured that it's clear? It took me 3 tries on an 87 yamaha 340, and I knew 'in theroy' what I was looking for.

They only other things, I can think of would be stuck choke drowning it out, or float stuck or out of adjustment.

I took the carbs apart again last night everything looks good and clean, no build up or blockages at all in the pilots. So does it sound like its not getting fuel or to much fuel? When you pin it from a idle or low rpm it bogs and sometimes spits & sputters (slight pop). The plugs are a cardboard brown color.

One way to narrow it down whether it's too much fuel or not enough, is to get into that failing condition and apply the choke at half. If it gets worse you already have too much fuel, and if it improves it's not getting enough fuel. Have you checked for exhaust obstructions. I don't think that would be the case if it runs fine over half throttle.

my old 440 indy trail did this! it had a cracked diaphram in the fuel pump, it was sucking fuel in through the crank pulse hose flooding out one cylinder, it took for ever to get it going but once u had it pinned and the rpms were up there it would run fine.

If you pull the choke it does get better.

I took the fuel pump apart it looked good. I still rebuilt it anyway but it did not help

Is all this correct? You symptom is that it won't idle once the choke is off and it's warmed up? You were able to get it to idle a bit by setting the air screw 1/8th turn out? You need to keep the throttle lever pressed in slightly to keep it running?

To me this still points to pilot jet. It's a $4.20 part, 3130065 (if I got the right model). I would start by replacing that and setting the air screw one full turn out, unless someone knows the correct air screw setting.

I think that is what Im going to do that next. The ones in the carb might be the wrong ones. I dont know who hand their hands on it before me.

And thanks to everyone thats helped me with this problem! Great forum