3120 unlimited coil source

[snowsalot]

Hi guys new here.
I have a husky 3120xp that i use for milling mostly softwood no larger than 20" diameter. It is limited to around 9000 rpm. it is continuously bouncing of the limiter even in the cut on smaller logs, it is driving me crazy. i know that there is possibly a coil from a 272 that will allow it to be unlimited but some say you need to adjust timing and some say you don't, maybe depends on model years etc. my question is is there a coil that I can buy that will definitely work on my 3120 to make it unlimited?
I also understand that this would probably mean changing carb settings on a "non adjustable carb" possibly by drilling jets to larger size, or modifying the carb to have a H adjusting screw.
Has anyone here done this type of modification? if so some pointers in the right direction would be greatly appreciated, Thanks.

 

[snowsalot]

OK I'm new here, I just finished reading the posts from a few years ago on the 3120 carb modification. I ll leave it alone on here. Sorry

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[rowdybernardropp]

The unlimited coil for the factory is the Black one or nonEPA from the 3120 Active railsaw or the K1250 Cutoff saw. They both have the coil you need. I found my thru Ereplacement parts out of Utah. The K3120, 3120W, 3120 Jungel, and 3120XP all have similarities. Yet, the K1250 has a different carb, Jug, and other mounts and so on. The 3120 type, use a WG2 thru WG10 Walbro. Yet the K1250 which is almost the same, uses a WGA 10-1 carb which has both bleed air screws but wont work because its backwards? Has to do with the jug and two timed port intake design. Now the K3120 Active and The K1250 are almost identical but I went with the K3120 because it had the ignition, flywheel, and carb I needed. It has the boss in the carb for the H bleed air screw just needs to be opened by a Walbro Tech or a Pro Saw Shop guru that has the right shaped machining tools and can do it properly. I have anywhere from $120 to $300 in the 5 carbs I have. I have seen 3 coils. The Lime Green limited, the Sky Blue EPA, and the Black coil. The Black non limited, non EPA coil is the one I have. It has 3 legs and 3 screw holes. The other 2 only have 2. If you have the limited or EPA powerhead, you also will need the Flywheel that is retimed for the coil. In between 20 to 30° BTDC I figured. The unlimited coil will not work on the EPA/limited it is retarded on time and is guttless and will bust your knuckles if you try and start it warm! So be careful! Now I have a FB friend whos on the FB account called Humboldt Loggers and Fellers he said if you really want that dude to scream, put a 372XP coil on it with the retimed flywheel. It will be the difference between night and day. He said its only limited by your engines ability to fuel and flow for the coil is unlimited. Now, last but not least. I run mine at a 32:1 right now. It was born a Non EPA saw but was set up for 50:1 and would not break 10K rpms. Now its right at 12K to 12.5K and gets better each time I pop it off. I figure the EPAs had to be leaned out to meet standards and this is why they wont let the coils rev past 9.6K rpms. If you rev past this more so under a load fair WARNING it leans the crap out of it and you WILL trash your motor!!! So, more fuel, Oil, and tighter air/fuel ratios. To do this means more denaro! Hope this helps you out. Ereplacementparts and set up an accout with your Email and goto the search box and put in Husqvarna 3120, 3120XP, K3120 Active, or K1250 CutOff saw. And match, browse, and compare. Theres more than 35 versions and years of the 3120 design. It was first built in late 1987 and had the WG2-1a with no choke and a foam filter and all three screws. H,L, and Idle. But used an fuel injector that squirted a shot of fuel into the air filter instead of the Choke. Where your choke is now is where the primer bulb did go. It was a 32:1 saw with a messy habit. It slobbered for 30 mins after you shut it down from the bar oil, and fuel dripping from the carbeurator area. But, some rated it as the same or higher than the 2100CD, 2101CDW! A Torque BEAST!!!

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[troutfisher]

I used a 272 coil. I had to re-grind the coil coil to fit the bigger diameter flywheel. I had the whole 272 saw.......so i put a degree wheel on it, set to TDC, and then marked the coil at where the leading edge of the magnet on the flywheel lined up. Now I had a timing mark. I put the coil on the 3120, with no flywheel key, set the crank at TDC and lined up the leading edge of the magnet with my timing mark. Tighten the flywheel down, the taper lock will hold it, no need for a key. Now you have a 3120 with a 272 ignition and timing.

 

[grizz55chev]

I used a 272 coil. I had to re-grind the coil coil to fit the bigger diameter flywheel. I had the whole 272 saw.......so i put a degree wheel on it, set to TDC, and then marked the coil at where the leading edge of the magnet on the flywheel lined up. Now I had a timing mark. I put the coil on the 3120, with no flywheel key, set the crank at TDC and lined up the leading edge of the magnet with my timing mark. Tighten the flywheel down, the taper lock will hold it, no need for a key. Now you have a 3120 with a 272 ignition and timing.

Toothpaste works to help lock the flywheel on, the abrasive adds friction after it drys. Nice McGyver fix though.