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Discussion Starter #1
Hi All

New to the forum but have an issue with my 2007 Grizzly 350 that I can't solve alone...

We've had it for 3-4 months now and always started and ran fine. Haven't used it for about 3 weeks and when I came to start it up it didn't want to know. Cranked over but would barely fire and ran really rough. I suspected clogged carb so I removed, stripped and cleaned it thoroughly but just rebuilt everything and it's still not happy. Starts and runs now but pops back through the carb and won't idle for more than a few seconds before stalling.

Done so far (having read many posts here):

Carb stripped and cleaned
Mixture screw replaced and set to the exact position it was originally in (2 complete turns out)
Valve clearances adjusted
Tank emptied, fuel tap removed and cleaned
Fuel cap vent cleaned
2 gallons of fresh fuel added
Carb cleaner sprayed down intake when running in case of sticky/gummed up valve (mostly just stalls when I do that)
Static timing marks on crank and cam checked and are aligned correctly at TDC

I'm out of ideas so would be grateful for any suggestions you can make on where to look next. Thanks!
 

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Discussion Starter #2
Today I fitted a new carb mount and O ring to replace the slightly cracked old one but it's not made any difference to the popping back and stalling problem I have at idle.

The engine will idle for a few seconds but then miss and stall. At low revs I get occasional popping back through the carb and a simultaneous 'knock' from the cylinder. At higher revs it's fine and plenty of power.

Any ideas guys on where I should look next?
 

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Welcome from Colorado.
I would check and set the valve lash, this requires confirming the cam timing is correct to adjust the valve lash.
 

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Discussion Starter #4
Thanks. Valve clearances/lash already checked and set. Inlet was slightly out but not much, exhaust was already OK.

To be honest the problem was the same before and after adjusting the inlet so I wasn't convinced that was where the problem was.

At the moment I'm a bit stumped on what to try next.
 

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Carb cleaner will foul a new plug, I would install a new plug and use starting fluid (ether) to get'er' going.
If you have the timing right, the top end in proper adjustment fuel and fire she should light up.
 

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Discussion Starter #6
The plug is new too. She fires straight up and runs, but with this occasional 'pop' and stall. Sometimes will idle fine for a minute or so and other times will stall almost immediately. Under power/revs is always fine.

Mixture is set where it was originally (when it ran well) so didn't want to mess with that.

Considering a carb rebuild kit next but don't want to just throw parts at it without good reason to think it's the cause...
 

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Discussion Starter #8
Not yet. I’m considering a carb refurb but also the possibility of a sticky valve. The head may need to come off to check that.
 
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