johnny7

Well Guys
I pulled the twin Keihen carbs off yesterday and took them down to the Polaris dealer. I had them check the needle and seats and they said that there was nothing wrong with them. I came home and checked them myself with a magnifying glass. No ring on the needle and seat was fine. These carbs are 39mm pwk carbs. I found a site that said the float should be 16mm from the base of the carb to the bottom of the float with the float just touching the spring needle on the needle itself. They were at about 13 mm and the float was actually bottoming out on the carb base. I set them at 16mm and reinstalled. This setting is still very close to touching the carbs . I immediately noticed better performance at idle. She use to load up with fuel sometimes even coming out the exhaust joints and was also boggy until you got going. No excess fuel and very peppy. I was popping wheelys on my back lawn.

Only problem I still got a table spoon of fuel out of the crank after I let her sit overnight, what ever is between the fuel shut off and the carb.
Does anyone know is 16mm the right height for the float.?? If I set it more will it do anything to the performance with a slight change?? I was also toying with the idea of installing a fuel shut off right at the carbs. That would eliminate the fuel from draining out of the line and the starting problem. The line fuel would not drain into the crank.

Some experience and help would be appreciated

tundrapolaris

Are both carbs draining into the crank? Try to determine which one is doing it by pinching off one line at a time that feeds each carb. Did this just start to happen all of a sudden or did you just get this sled?

johnny7

Hey Tundra
As far as I know the crank is seperated by a sealed bearing. Thats because the fuel pump only gets a pulse from one side of the crank.

Yes I'm getting fuel on both sides, so what ever is happening it is to both carbs

tundrapolaris

Very puzzling. Did you just get this sled or have you owned it for a few seasons. The reason i ask, has someone played around with it or did it just start doing this. Carb floats don't just go out of wack by themselves. Are the carb float bowl vents vented to the air box with hoses? Or has someone capped them? The only reason you are boggy in bottom is the excess fuel in the crank case (like leaving the choke on) That brings another thing to mind. Is your choke cable releasing the plunger completely?

johnny7

Hey Tundra
No everything is hooked up properly. The only problem is the fuel draining into the crank. The choke seems to be working fine. When you snap it off it doesn't hesitate to change.

I ve had the machine for a few years never drove it last year. Put 256 miles on it the year before that. That 256 is on a full overhaul. Sliders, bearings, pistons rings, cylinder deglasing, shocks, Machine is mint condition. She'll almost pull your nuckles out of their sockets in mid range. The problem was there after i put on about 150 miles when i bought it. I had the carbs apart last weekend, they were spotless inside. No tarnish or residue, no water. I'm just wondering if I need to set the float more. Couple more mm. Not sure what to do. Takes a couple hours to make a small adjustment.

John

tundrapolaris

What puzzles me, is why would the floats change. I've had multiple sleds and have yet had to adjust floats. I've seen where the float needle(check valve) has stuck or gotton dirt in it. Please make sure that the choke plungers are closing completely. When setting the cable for the choke (assuming this is single cable to the rack) it should have a tiny bit of free slack when released. The other thing i've seen multiple times, which will leave the excess fuel in the crank case,exhaust ect. is a partially plugged exhaust pipe, usually from mice making a next inside of it. They will usually start and idle but not rev well and act as if flooding. You adjusting the float may have created a bit of a lean mixture (kinda like running out of fuel) which may make it seem like you fixed it. You did say you had fuel coming out exhaust joints. A sign of incomplete burn and plugged exhaust. Its hard to determine if its plugged. It may seem like air flows through it fine but in fact when engine is running it needs more flow. The only way to get the s$$t out is to cut it and i'd hate to see you do that and it not be the problem. But i'm tellen ya i've seen it too many times. You could try a strong shop vac both ways. Let me know!

ppolaris1010

Does your sled have a primer?If not did you check your floats for having fuel inside them? Take the float off and shake it see if theres liquid in it.If not put new needle and seats in it there cheap.