Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Husqvarna => Topic started by: raumato01 on August 09, 2015, 06:23:05 am

Title: 266 backfires and then dies.
Post by: raumato01 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?
Title: Re: 266 backfires and then dies.
Post by: jmester on August 09, 2015, 10:45:40 am
It sounds to me like an ignition problem.
Title: Re: 266 backfires and then dies.
Post by: Cut4fun . 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. ;)
Title: Re: 266 backfires and then dies.
Post by: raumato01 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?
Title: Re: 266 backfires and then dies.
Post by: jmester 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.
Title: Re: 266 backfires and then dies.
Post by: Eccentric 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...
Title: Re: 266 backfires and then dies.
Post by: raumato01 on August 09, 2015, 06:22:53 pm
Cool, I'll check the gap and then the flywheel and report back.
Title: Re: 266 backfires and then dies.
Post by: raumato01 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.
Title: Re: 266 backfires and then dies.
Post by: wild262 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.
Title: Re: 266 backfires and then dies.
Post by: raumato01 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.

Title: Re: 266 backfires and then dies.
Post by: aclarke on September 20, 2015, 06:32:30 pm
I know you said you had the mechanic pull the flywheel, but was the key intact??
Title: Re: 266 backfires and then dies.
Post by: raumato01 on September 20, 2015, 06:35:41 pm
Yeah it was, nothing wrong with the crank or the flywheel.
Title: Re: 266 backfires and then dies.
Post by: aclarke on September 20, 2015, 06:40:21 pm
Two piece coil assembly! I.e main coil and secondary on left /rear side of case
Title: Re: 266 backfires and then dies.
Post by: wild262 on September 20, 2015, 09:16:16 pm
Yea usually the ignition module is the one that goes out 1st in them 2-pc. but again not allways.   I have noticed now that there are a few companys starting to offer new AM ones now on Flea-bay. Pricey though. Also, make sure there are no nicks on your plug wire and shorting out or crossfiring.  And  where the wire goes into the coil pack, they sometimes work loose for some reason.
Title: Re: 266 backfires and then dies.
Post by: raumato01 on September 20, 2015, 11:15:20 pm
I taped up the wire that had the nicks in it, no more backfiring but not running 100% smooth. I think I might replace the seals and maybe the coil.
Title: Re: 266 backfires and then dies.
Post by: jr27236 on October 04, 2015, 12:00:18 pm
Your coil is probably on its way out and you can get a new piston and jug for it Fairly cheap.  A meteor piston kit is sold at HLSupply.com for $30 if the jus looks good and not scored I would just do the piston and rings or just ring I  believe in the 266 case.

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Title: Re: 266 backfires and then dies.
Post by: mikehonda on October 25, 2015, 09:19:53 pm
ive got a good piston for that model i belive, ill measure it