Hey guys I bought a 99 600 rmk with a 151 for my little guy to play with on the lake previous owner says the top end is rebuilt. Also stated the sled haven’t ran in two years after I added new gas couple good pulls it starts and idles fine when I took the carbs apart to give them a quick clean and blow out I noticed it had 180 jets for the mains that seems a little small for southern Ab I looked into it they should be 185s and that would be the stock sizes. Also after running for a while it had a slights hesitating and was back firing at idle. After a bit of research and looking at the Kline carbs the air mixer screw was way out like in on one carb and half out on the other I adjusted to 1.5 turns out from all the way in now it idles great. Took it to the lake today for a couple hrs to play around on it zero to mid throttle works great mid to full it falls on its face and back fires lots the sled also has a primer kit on it so couple good shoots of fuel and it almost reaches full throttle. It feel like there’s lack of fuel? Also changed the plugs and went for a good rip and checked the plugs after about 10 mins they are on the slight brown side like light brown to white ish that mean lean. Also the air box has been gutted and new carb boots.
1999 Polaris 600 back fire
- Thread starter Jkure
- Start date
ABMax24
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What are the needles set at?
And is the ACCS system still installed?
And is the ACCS system still installed?
52weekbreak
Active VIP Member
Just curious if you have had a look at the reeds. Had an 800 ETEC that was not running right and turned out had cracked reeds on one side and a small chunk was missing. Worth a look maybe.
ABMax24
Active VIP Member
Possible, but usually bad reeds cause a sled to run like junk at low thrrotle/rpm, and run good at full throttle/rpm.
- Thread starter
- #5
ABMax24
Active VIP Member
How about the fuel pump? If its on its way out it may pump enough fuel for low rpm but not enough for full throttle operation. I believe there are rebuild kits for them.
Could also be a fuel filter, I believe they are basically just a strainer in the tank on those ones.
It shouldn't be the ACCS as it should fail rich not lean. And 180 vs 185 jets won't be enough difference to make it not run, melt a piston maybe, but it should still run at WOT.
My bet is a fuel pump or filter.
Could also be a fuel filter, I believe they are basically just a strainer in the tank on those ones.
It shouldn't be the ACCS as it should fail rich not lean. And 180 vs 185 jets won't be enough difference to make it not run, melt a piston maybe, but it should still run at WOT.
My bet is a fuel pump or filter.
I would try and find a stock box. I gutted my 99 700 and didn’t rejet and it acted very similar. Bare minimum you will likely have to jet up from stock with a gutted box. JMO.
- Thread starter
- #9
Ok yeah I was gonna order stock jets again I don’t need to burn a piston up lol. Is there away to test these vacuum fuel pumps? Looks like it had been changed before due to the mounting locations not being the same as stock. There is a inline filter I blew thru it and there’s no restrictions looks new. Also good point in gonna check the screen on the pick up end in the tank.
If you have to order them I would get the stock 185's as well as a set of 190's. You could also try raising the needle (drop the clip) to see if it helps the mid to full throttle. I really think the jetting and gutted box are the likely suspects. Good luck - would love to here how it turns out.
retiredpop
Active VIP Member
Do you still have the ACCS system hooked up? If not where do the carb vent lines run?
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