throttle hesitation

[coopersvilledump]

I just bought a 2007 nytro with 5000 mi. I recently cleaned the carbs, but this thing has a hesitation or a bog when i hit the gas. I have to feather the throttle to get it going or it sometimes stalls.I have let it warm up for plenty of time. I added a couple gallons of fresh gas along with stabil. It has new plugs and Holtzman springs. My old skidoo used to do this and I played around with the pilots. That solved the problem. Any info would be great. Thanks

 

[jamesc]

i'm new to sledding so i can't speak from experience with sleds but you may well be on the right track. due to emission restrictions all engines are being calibrated really lean these days. i had the carbs off my brothers sled recently but didn't look to take notice of idle mixture screws. if they're present they're often plugged to be "tamper" (read properly adjusted) proof. i have a DR200 dirt bike that was the most miserable engine i ever delt with (and i've delt with thousands) till i drilled the plug out and fattened up the idle some. if it has idle mixture screws you can try that.

 

[woolyviper]

RX AND RS carbs are notorious for plugged pilot jets. clean the carbs and it should take care of the bog. make sure the pilots are as clean as possible.

 

[coopersvilledump]

Well, I guess I will pull the carbs off again. I might even drain the tank and start with new fresh gas.

 

[jamesc]

don't think you got them clean first time? pilot jets are small and plug easily it's a good idea to get a small piece of wire and make sure they're clean. carb cleaner and compressed air helps.

 

[Metallicat]

Are you running it on the jackstand? Mine will bog and cut out while warming up on the jackstand if I'm agressive with the throttle. Mine has done this since it was new, these engines like to be warmed up for a while on a trail before you get into the throttle. I pull my pilots and mains every fall and let them soak in carb cleaner, mine wouldn't even idle this year after sitting all summer with a tank full of fuel and Seafoam stabil. Pilots were choked.

 

[Wertles]

I love to add Sea Foam as a stabilizer and as a carb cleaner. I haven't tried all the products out there but out of the 30 or so I have, it's the only one that I have EVER seen that has worked miracles. Lots of really crappy running engines have been brought back to life with that stuff around here. Expensive (around $9 bucks) but available everywhere.

 

[coopersvilledump]

I do have it on a stand and I let it warm up for a long time. I know my way around carbs pretty well and had them clean, but sometimes you have to do them twice. I will try seafoam. I have used it in the past with good results. I have never ridden this sled yet, so I do not know how it will run with a load on it. I am awaiting the snow. thanks

 

[Groomerdriver]

This is not a 2S engine so unless you want to gamble with burning down your motor, I would not play with the pilot sizes.

The pilots in these carbs are sooo small that you might think they're clean if you cleaned them the same way you cleaned a 2S pilot jet. Some people just go out and buy 3 new pilots instead of taking the chance that a wire will damage the orifice.

Also, IMO...carb synch is critical on these sleds to having them run top notch. I would have the carbs professionally synched if you don't have a good synch tool.

As Metallicat says, my carb'd 05 Vector will hesitate and burp a bit until it is completely warmed up. I have a digital temp gauge on mine so I can watch the engine come up to temp.

 

[hossZ28]

I just went thru the same problem with my 2006 Nytro I removed the pilot jets and main jets and soaked them in a paint can cap of Sea Foam to soften the algae or whatever you call the gunk then I gently took a fine oxy acetylene torch tip cleaner to help force the crud out of the jets then soaked them again and blew thru them with compressed air I like the sea foam product for fuel system cleaning but for long term storage I am experimenting with the Star tron product hope this helps also I agree on the carb sync these carbs dont take much to get out of sync and IMHO should have the sync checked every season!! I just noticed you say you installed the holzman carb springs I have read in other posts that the carb diaphraghms could rip or swell and not reseal in the chambers did the sled run ok before you installed the springs

 

[coopersvilledump]

Looks like I will be getting them synced. I just took them apart and the o rings around the mains are shot. So, I will replace them while I am in there. Now I have to find a buddy who owns a sync tool.

 

[Metallicat]

My carbs were way out of sync last year. I adjusted them and gained 600 rpm on top, back to where it was when it was new. It was running really crappy before the sync and was down on rpm. I purchased my own sync tool. It is pretty easy to do on your own and should probably be done every year. I'm going to do mine again this year.

 

[homer2210]

So if i clean my carbs do I have to sync them? Where do I get a sync tool and is it hard to do?

 

[tristan]

I had the same problem all last year but dealt with it on the 05 venture. This year I tried the seafoam and cleaning myself, better but not quite right. I broke down and took it to the dealer for a once over and sure enough, I didn't get the carbs completly clean and they were way out of sync.
All clean and sync performed, it purrrs like new.
I will be doing the work myself in the future but it's nice to have baseline of good performance.

 

[Metallicat]

So if i clean my carbs do I have to sync them? Where do I get a sync tool and is it hard to do?

You could have a dealer sync your carbs for you. I purchased the Morgan Carbtune for around $100 and it works good.