Viper backfiring out of carbs

hibshman25

Member
tya
Joined
Nov 10, 2004
Messages
30
Age
40
Location
Myerstown, PA 17067
I'm stumped on my buddies 03 viper.

Sled sat for a few years. Ran perfect when parked. Sled starts hard and when running it misses and backfires out of the carb. You can actually see the flashes when looking in the carbs. It only appears to be doing this on the mag cylinder, and center cylinder. The TORS system is by passed.

Today my buddy said he got it running again and it was still back firing and acting up. He had it running for a little and then noticed that the exhaust pipe was glowing red hot!

Could it be detonation from 2 year old gas? I did drain tank and put some fresh fuel in but it doen't seem to run any better.

Anyone have this happen before?
 

I would pull the reeds and check them out, if they are cracked or missing petals they need to be replaced. Bad reeds could also explain your hard starting.


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If its been sitting for 2 years the carbs need a good cleaning for starters. You building up heat in exhaust my bet is a mouse nest has clogged up things. Take it apart and give it a good cleaning.
 
Clean the carbs and check the exhaust for any restrictions like super1c said. Also while the carbs are off you might want to check the reeds and what the heck check and clean the powervalves as well.
 
Glowing red hot exhaust sounds like very lean. Definately check everything noted in the 3 posts above, and I would be inclined to at least pull the spark plugs and check condition of the piston domes as best you can. If there is that much heat in the exhaust, it was also very hot in the cylinders. If you have or can get ahold of an inspection camera that will fit thru the spark plug opening, it would be worth a closer look.
 
I would drain the tank and start over. Hope that there is no ethan poo left in there and that you can suck it all out. I would fish out the gas line and change the fuel filter in the tank. These sleds use a paper style gas filter clamped on the end of the pickup as the clunk instead of a weighted brass screen with an inline filter after the tank. Bad gas for sure, I don't care what was in it to try and preserve it that gas is junk now. I've gotten to the point where I leave my sled dry, it's just not worth the risk and by draining it in the spring that gas is still good and I can put it in my wifes car instead of throwing it away. You could have already passed dirt back into the carbs and plugged the jets. The reeds could be damaged from all that backfiring.
 


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