I tried to start my '98 Grizz today since it was a balmy 35 degrees. It's always started fine and gets year-round use. Today it tried to start and would stay running with the starter, then die. I could get it to run for maybe 10 seconds then it would die again. It sometimes seemed starved, then needed choked. There is a good fuel supply to the carb and there are no restrictions blocking the air to the carb. I do get an occassional backfire and other times it runs beautifully for all of 10 seconds.

I'm thinking maybe the problem is electrical now, but had to quit due to lack of light and frozen feet. Tomorrow I will check the spark's strength and consistency. Any ideas where to look for electrical or other related problems? Thanks in advance for any help!

 

Sounds like a carb problem/ fuel problem, to me. How old is the gas? If its more than 2 months old and you didnt add stabil when the gas was new....then the gas is bad.
The backfiring is usually a sign of lean carburation. Which could be a few things...fuel mixture screw out of adjustment, low float level, bad gas, dirty or plugged carb.

 

Thanks for your note. The gas isn't that old and has no stale odor, etc. The strange thing is that it seems to be flooded at times, then runs for a while (kind of cleans itself out), and then needs to be choked to fire again. That's why I was thinking it might be losing spark. It hasn't run enough to warm up to the point that it doesn't need choked. I might go ahead and try new gas just in case though!

 

It could be a vacum in your gas tank causeing it to back fire *a friend who went riding with us before thats what happened to his grizzly* He went down a hill and it backfired but the guy who we were riding with *another one* said take off the lid and it might start and he did and it started right up

so give it a try if u already didnt

 

The 600 Grizzlys are plagued with the Yamaha "dry rot" intake fiasco.

It's the boot between the carb and the "Y" aluminum intake on the head.
If it has any cracks, that is most likely your problem.

 

That would definitely explain its behavior, going lean and all. I can't wait to check that out tomorrow, thanks!!!

 

Just took it apart and checked the boot out. It was fine, still pliable and no cracks. Is there any chance that the decompression cam could be acting up? I was hoping that the intake boot was the problem! Any other ideas?

 

you also could had a little dirt or even if you have a little water in the fuel you could have ice in the bowl of the carb! it can get in the main jet and restrict it just enough to keep it from running right or create the problem your talking about where it only wants to run with the choke on also my bike in the winter will foul plugs ! they dont look too bad but i put a new plug in and it will fire right up

 

Keep checking for things which would cause it to run lean. Mixture screw, vacumn leaks, bad gas, low float, plugged passages in carb, fuel line/fuel petcock restricted, dirty fuel filter.

 

Thanks guys,

I will be checking into the fuel situation. The fuel flow is great through the filter, but I'm wondering about the ice idea in the bowl. I'm going to drain all of the fuel from the tank and carb and try new fuel. If that doesn't help, I'll take the carb apart and see what's going on.