03 Viper High Idle and Backfiring

Okay. I didn't get a chance to mess with it any more yesterday as I had other obligations, in lieu of hat I never got the chance to connect via phone for more assistance. I dont understand why things have changed with this machine and I would really like to, but anyway..... I took the carbs off again and verified fuel screw settings, they r slightly over 2 turns out. When I got it started it would not stop doing the same thing it did just a few posts ago. I backed the idle screw out a ton to start fresh. With the choke on it idled super high so as I let off the choke and it started coming down I started to meet it by screwing in the idle adjuster. It began to idle at 1800 like normal and was doing so just fine but I backed it off more and got it back down to about 1400. After a minute or so I brought it up to 1500 and left it. I took it for a spin and it runs well. Comes back down in what I would consider a normal fashion and idles well. Out of the hole it stumbles just a bit <--- is that an indication that one of the fuel screws is slightly off from the others? If so, would the plugs tell me which one after it idled for a bit and I shut it down? When I was out on my test run I stopped at my archery club and shot the air with some fellow archers for about half an hour. When I got back out to the sled it didn't want to start like normal. I'm interested to see how it starts tomorrow when dead cold. Its previously always started on the third pull. My apologies and gratitude to Mrviper700 and Ding
 

Yeah. Idles well at 1500 - 1600 rpm....usually stays at 1500… bump the throttle and it comes and it back down normal as I would consider it. Slight stumble if I pounce on the throttle from idle but then picks up again almost right away. It acts darn near normal but the settings aren't which is what gets me.
 
Yeah, I got over the settings. My guy told me "these settings work for our area", basically saying you have factory, and then you need to tune. He said as they age, and parts age, you need to compensate. I can live with that, my sled runs like a top!
 
Update on this thread which is way overdue. Got it so it would run, although it atill acted funny compared to "normal." Went out on the trail and was riding at 50mph and the center piston seized to the wall of the cylinder. I knew something wasn't right. I'm going back to my, it's a stock sled and everything should be stock settings just as they always have been in this area, mentality. Im just now getting to tearing it apart. It's been over a yr and with all the frustration, I just said screw it. Now I'm getting into it. Tons of flakes on the top of the piston. I haven't had the jug off yet but I've only found one area that looks to have build up on it rather than a groove or cuts into the cylinder wall. I'm certainly into territory I've never been in just by taking the head off. Regardless, there's no reason this should have happened in the first place so now I have to start all over and make it so it's all right.
 
Last edited:
Sounds like you had an airleak, this can happen when seals and gaskets get old and start to harden and crack. You need to preform a leak test to make sure the engine holds pressure, that is the only way to know you are leak free. This should be done on any freshly rebuilt engine as well as one experiencing problems.

Picture below is a tester I made on my srx. It should hold 6 psi for at least 30 mins to be safe. I have seen lots of leaks between the carb boots and engine, I could not get the stock gaskets to seal without some silicone.



 
You must log in or register to reply here.


Back
Top