Polaris 600 VES rich condition and fuel pump problems.
In the UP, my sled was running bad again. Really rich and fouling plugs. I'd have to pinch it to the bar and wait five seconds for it to clean out and run strong. Still ran bad when I got home. Low, crappy idle, some backfiring, and kind of weak and laboring in the upper midrange. Well, I borrowed Baller's fuel pump last night and my sled ripped. It idled and warmed up pretty nice with no attention, and then it ran clean and strong. It picked up the skis every time I pinched it, and it was way more responsive than in Michigan.
So what's going on? Baller's fuel pump has the stiff, clear plastic diaphragms like mine originally did. So when I rebuilt mine, all I could get was Mikuni rebuild kits that had kind of woven, tan, fabric looking diaphragms. They're quite a bit more pliable than the clear Walbro's, and they rip almost every time I ride. I've torn 4 of the tan Mikuni's now. So is this my problem? Is this why I'm rich, and where the heck do I get clear plastic Walbro rebuild kits?
Rebuilt fuel pump and new exhaust valve bellows solved the problem. Me and Gerbil put on 20+ miles today and my sled ran really well. It runs WAY better than it did in the U.P. Totally new machine compared to that trip. Gerbil's new sled (another Boonditcher Pro Model) ran well, but it has a midrange issue. It's kind of unresponsive at first, and then after being doggy it rips at the high end. We're going to check out the secondary for issues and see what we find in there.
I have a 2001 and a 2003. They both have new exhaust bellows and carbs were gone through and cleaned on both before season started. They have only been ran about 400 miles this season so far in the UP one weekend. They both have similar issues, plenty of snap from the start, but if you're running half throttle and mash it, they stumble anywhere from 1 to 3 seconds before they come alive. They don't always do it and can't do it consistently every single time. Sometimes it's good, then sometimes they're terrible. My 2001 seems to be worse. Both motors have good compression, as a matter of fact I just rebuilt the 2001 700 miles ago. The 2003 only has 3300 miles on it. They're both stock for everything. I could maybe see fuel pump for the older of the 2, but for a sled w/3300 miles to have the same issue, I don't know? I go through these sleds with a fine tooth comb year round and they are maticulate inside and out, I just think I am missing something here. Any help is appreciated!
Stock is in the number three slot. (Counting from the top) Setting it in number two will help clean up the midrange.
If you have a really bad fuel pump, you will know it. If you leave the fuel on overnight, you will fill the crankcase with gas. I think last spring I had a leaking needle and seat. I flooded the case, and then I tried to start it and the added pressure coming through the impulse line tore the fuel pump. Then I had fuel running through the pump after I'd dealt with the needle issue!
In my opinion, the fuel pump should be fine unless you had backfiring or flooding issues in the past. Both of those things will wreck your fuel pump. Our Ski Doo dealer in town says they haven't seen a fuel pump failure in almost 30 years. Believe that if you want, but that is an indication that a fuel pump problem might be rare if there hasn't been any issues that might cause it to fail. If you are curious about the pump though, it is very easy to check on those sleds. Remove three hoses and two nuts, and it's off. Then just pop it apart and carefully inspect all the diaphragms in there.
I'd really check that jetting first. Go run one of the sleds for awhile and pay close attention to how it runs in those conditions. Then drop the needles one slot and run it again. You should feel a positive change. You could change the mains after that. You should feel more gains after doing that. When you have the carbs out for the jetting change, check your float assemblies (needle and seat) for problems.
Another problem you might have is your TPS. Unplug the TPS harness from your carbs. It's the rectangular plug on the mag side top of your carb rack. If it runs better with it unplugged, you may have a problem there.
Thanks a ton! I will check the needle clip first. I am assuming that if they have never been moved, they're in the 3rd spot. I will try the worst sled first and let you know. Thanks for the link too. I don't think it's a fuel pump personally either because they never get flooded or start hard. They start cold or warm with no problems. They don't seem to get fat until after you roll into the throttle all the way to 1/2 - 3/4 throttle. Thanks again Rubi !
I just moved my e clips up to the 2nd notch to lean things out a bit and gonna drop in another new set of plugs to test it out. What would be a good gap to set at? Right now I am gapping .035, but is that too much?