Homelite XL-76 coil swap

[Old2stroke]

Just had a light bulb moment. It finally occurred to me that what you were calling a mounting bracket is the actual laminated iron pole piece of the coil. Now that I understand what you have done, I may give it a try, it could be faster than making another mounting bracket for the whole module.

 

[Smoothops]

I have 6 Poulans ranging from the cheapies to the 50cc Poulan Pros and they all have to same coil, none of which have the bracket you had to remove. Unfortunately I sold the only Wild Thing I had, so can't use the coil off it. I find it strange that it used a different coil configuration, I always thought it was the same as the other saws in the line up. I have a spare coil for the Poulans so I'm going to try it hoping it operates the same as a Wild Thing coil, just have to make yet another bracket to mount it in the XL-76. The L mixture screw only adjusts the mix for idle speed. It's the H screw that sets the mix for high speed full load operation and it's important to have it set so rich that it has a distinct burbble sound to the exhaust (called 4-stroking) when running at full throttle with no load but cleans out and runs with a crisp sound as soon as it start to cut.

Thanks for the info, I know what 4 stroking sounds like and I thought I heard it when accelerating the saw. However, I did not opened to full throttle as it had no bar or chain when I was playing with it, so what I heard may have been fuel starving sounds. I will open the high screw at 1/4 turn increments until it sounds and behaves better. This is the coil I used, notice the connector is positioned in a way that does not interfere with the Homelite XL76 iron core bracket, which has another arm that extends towards the top right end of the coil. That longer arm has another hole for the second fastener. The iron core bracket I removed from the poulan coil is the metal part in the picture, which has one arm going down on the side of the coil and another arm which is factory pressed to go through the center of the coil. That is the one that has to be pushed out of the coil and it is a tricky endeavor to do so. I'll take a pic of the coil installed on the saw and will upload it, for your perusal.

 

[Smoothops]

Just had a light bulb moment. It finally occurred to me that what you were calling a mounting bracket is the actual laminated iron pole piece of the coil. Now that I understand what you have done, I may give it a try, it could be faster than making another mounting bracket for the whole module.

Bingo! The whole thing was a case of miscommunication. I call it "bracket" for lack of a better word, but I have edited all posts to give it its proper name, iron core. Here is a pic of the mounted coil

 

[Smoothops]

and a closeup. Notice the original homelite laminated iron "bracket" is longer than the Poulan. The copper piece attached to the cylinder (adaptor plate) has the two threaded holes to fasten the coil. I looked up the number and found this: Ignition Coil Module 530039198 - Wildthing Craftsman Poulan 2050LE 2055 Chainsaw. ... For Poulan / For Craftsman Chainsaw Ignition Coil Module Replace 530 039 198.

 

[Smoothops]

It is also found on some of the weedeater trimmers
530039198 Poulan Craftsman Chainsaw

 

[Old2stroke]

Thanks for the part number info, it turns out to be a same as my spare Poulan coil but the coil is molded right to the core and couldn't be removed without damage. If my Chinese coil on order doesn't show up soon I'll think about making an adapter mounting bracket.

 

[Smoothops]

Thanks for the part number info, it turns out to be a same as my spare Poulan coil but the coil is molded right to the core and couldn't be removed without damage. If my Chinese coil on order doesn't show up soon I'll think about making an adapter mounting bracket.

That's what I thought when I did mine. Would you post a pic of yours so I can compare it with what I have? Mine did look molded, but it slipped out without damage. If you use the donor's coil iron core, your timing will be off, as the timing on these saws is determined by the position of the 2 legs of the iron core that interact with the flywheel magnets. These legs have a specific width, angle and position, so you must use the original iron core. This is why the first one you did was not successful

 

[Old2stroke]

• Not necessary to use the original core as long as the footprint of the two core ends matches the ones on the replacement and the replacement is meant for the same diameter flywheel. I have replaced many coils without using the original core. In the original blue coil the primary and secondary windings of the coil are all wound on a bobbin and the bobbin plus the electronic components are potted in epoxy and then the assembly is secured on the core with shims and sometimes a bonding agent. Few coils are made like that anymore. Most of them are constructed by placing the wound bobbin mounted on one leg of the core and the electronic components in a plastic form and then the form is filled with epoxy and heat cured forming a solid potted assembly that is now bonded to the core and very difficult to take apart. Unfortunately, I don't have a camera that will do good close up work.
• When I'm trying to adapt a new coil, I check the timing by driving the crank with an electric drill and using a timing light to check the low speed timing. For easy starting, the timing should not be more then about 12 deg BTDC and advance to 25 to 30 degrees at high speed. The coil I tried was fixed at about 30 deg which is way too much for starting. I tried moving the timing around by modifying the flywheel key but couldn't find a good compromise. These coils cannot advance the timing beyond the basic timing point where the pole ends of the core are lined up with the flywheel magnets, they just retard the spark by a max of 5 to 10 degrees from the basic timing which on the XL-76 is about 30 deg so the coil I was trying either had a defective retard feature or it was meant for an engine with fixed timing. All the older saws with points type ignition have fixed timing which is usually 15 to 20 deg that can be varied slightly by the size of the points gap. So far I have not seen a saw with a modern ignition module that is meant to operate with fixed timing but there may well be some out there.

 

[Smoothops]

One can only show a horse where the water is.....