Author Topic: 61 or 266 to 272 builds.... a fix to an issue  (Read 216 times)

0 Members and 0 Guests are viewing this topic.

Offline weimedog

  • 6 cube
  • ****
  • Posts: 260
  • Karma: 57
61 or 266 to 272 builds.... a fix to an issue
« on: May 15, 2015, 07:57:46 pm »
A humbling experience, but one worth passing along. I've done several of those early Husqvarna 61/266 to 268/272 conversions. But none really had to work a real job. Like mine, most would get run for an afternoon and then sit the shelf in retirement for a couple of years before being brought out to entertain at GTG's or some such event, then get put back on the shelf.

I built a 266 "Twin coil" ignition with an upgraded top end, a 272 to be exact with a 272 manifold and carb as well. Mild muffler mod to top it off for a guy who mainly used it for firewood. That was three years ago. Then last fall he brought it to me because it had quit.... the old original ignition had fried. SO I ebayed an OEM replacement,  made in Brazil. Ran. Sent it back.... he starts working full time for a logger and also starts picking up  his own work. NOW that saw is being run 8 hours a day, 6 days a week! And he brought it back again.....I couldn't figure it out. It would start, idle, but wouldn't rev past 10k. Almost like a rev limiter. SO I do the usual... nothing helps... out of desperation I swap ignitions with my 61/272 and its... better. Good enough to send back.... and then its back in my shop a week later. In the mean time, I've lent him a saw so he's not out a saw and doesn't miss any time working.... he's still happy, but I'm.... frankly embarrassed. Never been stumped like that before.

SO>>>> Now I start really looking this situation over, as I should have from the get - go. AND notice signs of arcing between the spark plug wire and the cylinder.

Remember.... the 61 cylinder is SHORTER than the 272 and so is the ignition wire. Out of shear frustration, I yank the plug wire out of that OEM Brazil coil (The small one with that plug wire) and put a longer one in that I have from an old Jonsered something....

Instant change. Power is back. RPM's back. The saw is back to its "no base gasket - 272 cylinder - muffler modded - intake at 78 BTC" self.

Moral of the story???? Follow your instincts. AND when you make those hybrids remember that the plug wires on those two coil systems are TOO SHORT!!! ???

Share on Facebook Share on Twitter

Like Like x 1 View List

Offline 660magnum

  • Global Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 6437
  • Karma: 249
  • For The Love Of Chainsaws
  • Location: NCO
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #1 on: May 15, 2015, 09:48:38 pm »
Changing the subject slightly . . .

But regarding the black coils on the 3 series Husqvarnas. Ones for different saw models have different part numbers but the coils look alike. The difference is the length of the plug wire.
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

Offline Spike60

  • Piped Saw
  • *****
  • Posts: 340
  • Karma: 110
  • Location: Ulster County, NY
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #2 on: May 16, 2015, 06:45:53 am »
So, that's what it was! I've seen that several times on the 3 series saws. Just putting an original 372 coil in an XT will get the same issue you ran into. But usually it won't appear until the cylinder fin actually wears through the insulation on the plug wire.
Husqvarna-Jonsered

Ashokan Turf and Timber

845-657-6395

Offline Eccentric

  • Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 2110
  • Karma: 217
  • Magnesium and Iron.
  • Location: Northern California.
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #3 on: May 16, 2015, 02:18:36 pm »
That's the kind of problem that will make you tear your hair out.......
-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 Spike60

  • Piped Saw
  • *****
  • Posts: 340
  • Karma: 110
  • Location: Ulster County, NY
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #4 on: May 18, 2015, 07:27:40 am »
We've talked about this ourselves a bunch, but it'd be interesting to see what other guys here have to say about a saw "working a real job" vs the limited trigger time most of our builds see. They are two very different realities. If he is working all day in the woods, he is putting as much time on that saw in 2 days as he would cutting a year's worth of firewood. We have so many saws that if we run 2 or 3 tanks through them before grabbing something else it's a lot. Doing a few timed cuts or a couple loads of firewood might tell us how good a saw runs, but not how well it will hold up. This gets us into the questions about using aftermarket parts or building silly compression into a real work saw.

Another thing to point out here is that Critter, (the owner of the 266 for guys that don't know), has changed those parameters himself here. Taking a near 30 year old 266 that was intended as a firewood saw into the woods as a full time logging saw puts that saw in a very different role. I know guys like him and Nathan are guys you can trust, and they can help field test some of the saw mods. But loaner saws, particularly when out for weeks at a time WILL create some awkward moments in your life.  :P  Gotta be real selective there, and at the least only loan out the power head. No need for them to wear out your bars and chains. Selective also in regards to certain "emergency" type situations. Don't want to create the expectation that every time a saw goes down, a guy gets a loaner. People take advantage of good intentions like that. 
Husqvarna-Jonsered

Ashokan Turf and Timber

845-657-6395

Offline weimedog

  • 6 cube
  • ****
  • Posts: 260
  • Karma: 57
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #5 on: May 18, 2015, 06:48:14 pm »
I  agree on all points... for the loaner saw I've using the "Huztl 372" and its had a pile of run time on it now. To me that's testing as I certainly wouldn't put the kind of time on that particular saw as they have... But I agree, no one is getting either my "new favorite saw" (365/372xpw) or "Cyclops! Those are my personal saws and the work they do will be what I do myself. And "critters" world changed and he's went full time felling this winter. A different saw than the 266 is in his very near future. Actually two, one big and one small. Thinking about letting him trade that 266 as its really clean.

And to review, one of the reason that saw is in the loaner saw rotation is in fact to get it real life in the real  working world to see how it survives and responds to those situations and even repairs. The life of a saw.... just condensed in a way I couldn't/wouldn't do myself. I want to run the saws I'm interested in at the moment... and as you have pointed out that changes weekly so many saws never even get a thorough break in!

Offline Spike60

  • Piped Saw
  • *****
  • Posts: 340
  • Karma: 110
  • Location: Ulster County, NY
Re: 61 or 266 to 272 builds.... a fix to an issue
« Reply #6 on: May 19, 2015, 06:53:03 am »
Aother thing is that as your shop grows, loaners are no longer feasible. I've got about 30 saws in the shop at the moment. (all but 5 of which are done). Sure can't have that many loaners. And guys are slow enough as it is picking up their own saws. Give them a nice loaner and they might never come in! LOL . But seriously, most guys who really need a saw have more than one; which partly explains why they don't rush in to pick them up when finished.
Husqvarna-Jonsered

Ashokan Turf and Timber

845-657-6395

 

Related Topics

  Subject / Started by Replies Last post
8 Replies
617 Views
Last post August 30, 2012, 12:53:08 pm
by Remington
22 Replies
614 Views
Last post January 24, 2016, 05:16:42 pm
by Reddog
5 Replies
715 Views
Last post January 25, 2014, 03:07:17 pm
by Infinitive
8 Replies
314 Views
Last post April 13, 2014, 10:13:50 pm
by 3000 FPS
30 Replies
410 Views
Last post November 02, 2014, 11:32:40 am
by TommyC
8 Replies
117 Views
Last post September 30, 2015, 09:14:25 pm
by jmester
4 Replies
251 Views
Last post October 19, 2015, 07:20:58 pm
by jrdplowing
0 Replies
247 Views
Last post October 17, 2015, 03:31:43 pm
by jrdplowing
3 Replies
225 Views
Last post February 21, 2016, 01:21:50 pm
by Old Iron Logging
0 Replies
124 Views
Last post December 18, 2017, 12:08:27 pm
by weimedog