07 450 Grizzly will not idle, pop through intake - Yamaha Grizzly Forum : GrizzlyOwners.Com Yamaha Grizzly Forums

sulacracker01 · 01-17-2012, 01:46 PM

I have a grizzly that will not idle, ithe exhaust wants to backfire and it is poping through the intake. The valves seem good, the jets are clean. I do not know where to adjust the air/fuel screw. That is the only thing I could think it is. I put a new spark plug in it... If anyone knows what is causing this, please le me know. If not I think I am going to order a new carb this week. Thanks

mbudzynowski · 01-22-2012, 05:05 PM

The air/fuel mixture screw is on the bottom middle of the carb towards the front where it goes into the intake boot. How does it act when you give it throttle? What about when the choke is on? My 660 did this when it was cold, I took the carb apart and cleaned everything out twice and it didn't change it, then I checked the valves and they were way tight, I adjusted them and it ran like new.

Also, did you take the jets out of the carb to clean them and possibly switch them? I don't know if you can do that on your carb but I did that on my buddy's Warrior and it caused the same problem you're having.

gregp · 01-28-2012, 10:04 AM

I agree with this. Check your valves! Be certain that they are not too tight. If they are OK, then you probably have low speed carb circuit troubles (pilot jet clogged, air leak, etc.). You can adjust the fuel screw, but you will need to remove the carb, and drill out the small brass plug that is covering it up. The fuel screw is located on the "engine side" of the slide, in the center of the carb (longitudinally), on the bottom. Use a small drill bit to drill only through the cap, then use a small sheet metal screw to pop the plug out. You can discard it after you get it out.

01-17-2012, 01:46 PM	#1 (permalink)
sulacracker01 Junior Member Join Date: Jan 2012 Posts: 1	07 450 Grizzly will not idle, pop through intake I have a grizzly that will not idle, ithe exhaust wants to backfire and it is poping through the intake. The valves seem good, the jets are clean. I do not know where to adjust the air/fuel screw. That is the only thing I could think it is. I put a new spark plug in it... If anyone knows what is causing this, please le me know. If not I think I am going to order a new carb this week. Thanks

01-28-2012, 10:04 AM	#3 (permalink)
gregp Junior Member Join Date: Jan 2012 Posts: 5	I agree with this. Check your valves! Be certain that they are not too tight. If they are OK, then you probably have low speed carb circuit troubles (pilot jet clogged, air leak, etc.). You can adjust the fuel screw, but you will need to remove the carb, and drill out the small brass plug that is covering it up. The fuel screw is located on the "engine side" of the slide, in the center of the carb (longitudinally), on the bottom. Use a small drill bit to drill only through the cap, then use a small sheet metal screw to pop the plug out. You can discard it after you get it out.