High Quality Chainsaw Bars Husqvarna Toys Hockfire Saws

7900 coil swap

acp104

Super OPE Member
Local time
4:39 PM
User ID
546
Joined
Jan 15, 2016
Messages
6
Reaction score
31
Location
NW Illinois
Rich (Poleman) definitely has the most info on this, but I'll throw some comments in here for now figuring he'll come along later. 272 coil is what I was told. This appears to be the one I used: http://www.ebay.com/itm/Ignition-Co...340831?hash=item43e2f253df:g:TawAAMXQhpdRsK8F . And I've attached a pic of it installed and an example of where material has to be removed from the mount to make one fit. Use the existing coil wire, but reroute it behind the coil between coil and case. I used one small washer between the mount and case for each screw to get a hair more clearance for the coil wire, then a washer on top to make up for the hogged out holes in the mount. I used a .010 feeler gauge to assure proper air gap between flywheel and coil, but a business card is fine too. Its a tight fit, and you'll wish the coil wire was longer. You can gain a little wire length by removing the clips that hold it in the case behind the flywheel, pulling a little more, then reinstalling the clips. If you saw much of the thread on AS, you know you need to grind the cast in key out of the flywheel and advance the flywheel 3o degrees to make the coil work. Once that is done, at least for me, it was tricky to get my flywheel tight enough to not slip and maintain proper timing. I'll let someone else like Poleman elaborate on the timing change, since I had some problems, and eventually sent my saw to Carl Miller to iron out the timing and port it. Carl actually cut a keyway in my flywheel at the proper position for the 272 coil and installed a key. I'm not saying that retiming it should be too difficult, but it ended up being a problem for me.

Since Mastermind and some others are working on producing a bolt on unlimited aftermarket coil for these saws, I'd probably hold off awhile on this mod and see if that comes together sooner than later before I permanently altered my flywheel.
 

Attachments

  • IMG_20150806_195436614.jpg
    IMG_20150806_195436614.jpg
    126.4 KB · Views: 53
  • Coil mod 2.jpg
    Coil mod 2.jpg
    68.9 KB · Views: 49
Last edited:

mdavlee

Hillbilly grinder
Local time
5:39 PM
User ID
279
Joined
Dec 28, 2015
Messages
14,194
Reaction score
64,604
Location
TN
Country flag
Matt is working on his now. I sent it back with 3 coils. One Oem with pressed in husky laminate, oem, and a 272 husky coil. I didn't get it dialed in on one so I swapped another on and then sent it to him.
 

WKEND LUMBERJAK

Here For The Long Haul!
GoldMember
Local time
4:39 PM
User ID
394
Joined
Jan 3, 2016
Messages
4,978
Reaction score
21,580
Location
West of Kansas City
Country flag
Matt is working on his now. I sent it back with 3 coils. One Oem with pressed in husky laminate, oem, and a 272 husky coil. I didn't get it dialed in on one so I swapped another on and then sent it to him.
Is he working on the one you built. That thing is a animal.:):)
 

cgraham1

Here For The Long Haul!
Local time
2:39 PM
User ID
257
Joined
Dec 26, 2015
Messages
4,549
Reaction score
18,848
Location
Nor Cal
Country flag
@Poleman ...

I personally hate the rev limited coil. I am waiting for the AM unlimited coil to come out, because I don't wanna mess with moving my flywheel and all that other stuff.

I ain't smart like some of you guys.
 

Hedgerow

ONE OF THE GREATEST.....LONG LEGGED MIDGETS
Local time
4:39 PM
User ID
316
Joined
Dec 29, 2015
Messages
11,647
Reaction score
73,424
Location
SW MO
Country flag
And it's proving to be more of a task than one would think. Cause if it ain't just right, the saw will run, but not to it's potential.
 

acp104

Super OPE Member
Local time
4:39 PM
User ID
546
Joined
Jan 15, 2016
Messages
6
Reaction score
31
Location
NW Illinois
And it's proving to be more of a task than one would think. Cause if it ain't just right, the saw will run, but not to it's potential.
I thought I had mine pretty close, but it didn't want to hot start. I went back and messed with it, and never could get it that close again. Its real important that things are reference marked correctly before grinding out the key, or you're in trouble without another stock flywheel handy. I'm sure guys that are used to setting up a degree wheel on a saw would have no trouble, but easy for a greenhorn to screw up.
 

Mastermind

Chief Cat Herder
Staff member
GoldMember
Local time
4:39 PM
User ID
4
Joined
Dec 3, 2015
Messages
48,626
Reaction score
316,683
Location
Banner Springs Tennessee
Country flag
Good stuff guys. I managed to get one to run with a Poulan Wild Thing coil. The problem is that the wire in those coils is epoxied in. :(
 

Hedgerow

ONE OF THE GREATEST.....LONG LEGGED MIDGETS
Local time
4:39 PM
User ID
316
Joined
Dec 29, 2015
Messages
11,647
Reaction score
73,424
Location
SW MO
Country flag
Just keep advancing the ignition until it starts like my 385:D
Lol...



No...


Went back with stock coil, a few degrees advance, and boo yaaahhh!!!!

The mutt is pissed, and wants unleashed!!
 

Miller Mod Saws

Chainsaw Masseuse
Local time
4:39 PM
User ID
317
Joined
Dec 29, 2015
Messages
2,037
Reaction score
8,808
Location
Ravenwood,MO
Country flag
Kenneth I just seen this. Ill let poleman explain as he had very detailed pics and procedures. But just give me a jingle and I can walk ya threw it. It's not that bad. Definatly easier for me if I use a degree wheel. :)
 

Adirondackstihl

Vert Da Furk........Bork Bork Bork
Local time
5:39 PM
User ID
17
Joined
Dec 4, 2015
Messages
5,917
Reaction score
25,619
Location
Upstate NY
Country flag
There are (2) different OEM coil/flywheel combos for the 7900.

That's about all I can contribute
 
Top