Author Topic: 266 backfires and then dies.  (Read 866 times)

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Offline raumato01

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266 backfires and then dies.
« on: August 09, 2015, 06:23:05 am »
I just bought a 266 project, it was complete so I started it up and it ran for a few minutes nicely then it started backfiring and then it died. It started again and idles nicely but when you give it throttle the backfiring started again.
I'm thinking either air leak , seals or maybe an electrical short? Any thoughts before I start tearing it apart?

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Online jmester

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Re: 266 backfires and then dies.
« Reply #1 on: August 09, 2015, 10:45:40 am »
It sounds to me like an ignition problem.
FEAR NO TREE. FEAR GOD.

Offline Cut4fun .

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Re: 266 backfires and then dies.
« Reply #2 on: August 09, 2015, 11:56:19 am »
Start cheap. Try a known good plug.  Had this type deal happen to just be a bad plug before. If you get lucky. ;)
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Offline raumato01

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Re: 266 backfires and then dies.
« Reply #3 on: August 09, 2015, 02:12:15 pm »
Cheers for the replies .Changing the plug was the first thing I did and nothing changed , so next I go over the wiring and see if there are any cuts or nicks in it? What are the chances of the flywheel being an issue?

Online jmester

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Re: 266 backfires and then dies.
« Reply #4 on: August 09, 2015, 02:27:58 pm »
How does the magnet look? My guess would be the module. I would also check your air gap.
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Offline Eccentric

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Re: 266 backfires and then dies.
« Reply #5 on: August 09, 2015, 06:09:47 pm »
Could also be a sheared (or missing) flywheel key.  If the FW is not positioned right the timing will be off...
-Aaron

For older saws:
Tune the H side so that it 4-strokes (burbles) at WOT unloaded and just cleans up when under load.
When you lift cutting load, the saw should immediately revert to 4-stroking.  Fine tune the transition point for the wood you're cutting.

Offline raumato01

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Re: 266 backfires and then dies.
« Reply #6 on: August 09, 2015, 06:22:53 pm »
Cool, I'll check the gap and then the flywheel and report back.

Offline raumato01

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Re: 266 backfires and then dies.
« Reply #7 on: September 19, 2015, 10:58:56 pm »
Well it isn't the flywheel, took it to a small motor mechanic to get the flywheel off and he said the compression was low which could let unburnt gas through. So much for a cheap project, I might put a new meteor piston in it.

Offline wild262

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Re: 266 backfires and then dies.
« Reply #8 on: September 20, 2015, 09:39:44 am »
     Not sure that's the problem.  What was the compression reading?  Did he show or tell you?  I have had saws that ran fine at 115-120 lbs. outside of being alittle low on power.  Most dealers would say to that, "you need a rebuild".  You may have other issues in addition to that.  Check the ignition system first, esp. the coil before you spend your money on a rebuild, or another saw.  Could be a carb issue as well.  Just don't be to hasty taking a dealers word for it.  Some are very dishonest and just want to make a sale.  Good luck.

Offline raumato01

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Re: 266 backfires and then dies.
« Reply #9 on: September 20, 2015, 06:22:05 pm »
Thats good advice, but I should have mentioned the guys not a dealer he has a little workshop and just services outdoor gear. He pointed out theres a nick in one of the coil wires which might short out and said it will need at least new rings although it does still run ok but like you said down on power.

I think you're right and will try heat shrinking the nicked wire first and then work up from there.


 

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