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Discussion Starter #1
My old trusty 366 has been acting up. Starts right up when cold and runs fine. Last two times I ran it, it would sometimes be very hard starting. Cranking with no fire. Sometimes would take up to 2 minutes to finally get it to start. Did notice fan wasn't running much, so I suspected it was running too hot. Dug into today, first changed the spark plug, didn't look bad, but figured it couldn't hurt to eliminate it. Dug into the wiring and discovered an intermittent connection to the fan sensor. Re-soldered it and started it up and let it idle and the fan came on like it should and shut down as it should. Ok so now its running at the right temperature and the cooling is working. Shut it off, let it sit for a few minutes, sure enough, hard starting. It was not as bad as before, but still took 20-30 seconds before it kicked over.

Last year the valves were checked and adjusted, this quad doesn't get many miles put on it as its the spare machine so I doubt they are out of adjustment again.

I also made sure it had fresh gas, I do use Sta-Bil with this machine since it does sit for awhile.

Any ideas what to look into next?

Mike
 

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It does sound like the starter jet may have crud in it.
 

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Discussion Starter #3
I do have an inline fuel filter installed. Would think it would prevent that
 

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You could check the coil output to be sure it’s in spec and make sure the plug wire/boot are in good condition.

Is it turning over fast enough ?
 

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Discussion Starter #5
Yes turning over strong. Battery is in good condition. Replaced the spark plug and looked over the coil, wire and boot.
Did not meter the coil out, could try that next

Mike
 

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Discussion Starter #6
With the changes Arctic Cat has done, I no longer have a dealer in my area. He took care of stuff that I couldn't do.
Ive never messed with a carburetor before, do you have a suggested video I could watch to try it myself?

Mike
 

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Discussion Starter #8
Thanks, I bookmarked it to have it handy in the future.

I think I may have found the issue. Yesterday I pulled the coil and tested it. Everything tested corrected according to the manual. I fired up the quad and let it heat up until the fan ran. Shut it off and within a minute, cranked it. It fired right back up. I did this two more times and each time it started right back up. Let it sit for about 10-15 minutes and guess what, would not start. I had the seat and side panels off because I was doing these test and then I noticed that the fuel filter had no gas in one end. The line from the side that was empty leads to the carburetor. So I cranked it and slowly it started filling back up with fuel and then it caught and started (sputtered at first, but exactly like how its been acting) Once the fuel filter was refilled, it idled normally. This is exactly how its been acting. Once I get it started, it runs fine.

During the time it wouldn't start, I pulled off the spark plug boot and used a spare plug to verify that I did have spark and it was strong. That eliminated the coil assembly as an issue.

Apparently the last time I had it in for service the dealer replaced the fuel filter and routed the fuel line over the intake creating a hump (vertical rise) in the line. Since this is an air/oil cooled machine, the operating temperature is higher then a liquid cooled machine so I am thinking the gas is boiling off inside the carburetor and emptying the fuel line up to the filter.

I routed the fuel line under the air intake so its lower so I will see if this makes a difference. It was later in the day so I did not have time to run another test. I think this is the problem. Pictures are kinda crappy, but you can see what was going on.

Mike
 

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That is definitely plausible.
 

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Discussion Starter #10
Rode yesterday and did not have any problems with hard starting so I am confident that was the problem.

Mike
 

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Discussion Starter #11
One thing that did happen is the rear bearings in the quad were bad. Looking back in my logs I changed these out three years ago, but had only put on 550 miles since replacing them, that was weird. I always use the Koyo bearings and they should have lasted much longer.

Mike
 
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