Husky Coil College

[Stump Shot]

They used to sell spark wire in lenght, if you ordered 5 spark wire you got one long wire.
Husqvarna themself claim they're cutting them nowadays 13" lenght, can't remember it's part number, the only one I found is # 501 53 16 01, if you order 5 you may get a 65" cable, or you may get 5x13"

Thanks Tor.

Update on the last 254 coil I bought from Husqvarna, it came in as "Made in China".

 

[Tor R]

Thanks Tor.

Update on the last 254 coil I bought from Husqvarna, it came in as "Made in China".

That be damn Steve, they're going downhill!!

I've worked with 2 fresh 254 builds last week, they've won't complete comparative, timings & advanced timing is very close, will run them with 198 carb & mm's.
Got at least 3 different coils where all of them comes from the era where Husky advanced their timings, one of them is a Ducati coil.

 

[Michael Rupley]

One thing always bothers me about coil advance. I just don't know about electronics but it seems to me that, The ignition can not advance timing. I can understand retarding electronically or holding the spark a little. This will definitely help on the starting and then the spark will go to the default position. I just can't understand how the ignition can anticipate when the magnets may be coming around and spark before the magnets excite the coil. If I am right about this shouldn't we be referring to a coil retarding and not advancing?

 

[PogoInTheWoods]

That's how I look at it. I don't see how a coil can react to an electromagnetic event that hasn't happened yet unless it's retaining voltage from a previous revolution based on an rpm threshold programmed into it to pre-trigger spark before the next pass of the magnets..., and somehow also shunts (or stores) that next pass to not interfere or double trigger at the prescribed rpms on so on.

 

[Sawrain]

Think of it another way around.

Lets say the coil/flywheel are Aligned to fire at 30 degrees btdc without the electronics in play.

During starting, idle and rev limiting the spark is delayed, retarding ignition to a lower figure than 30°, then at 9-10k rpm in the cut the electronics just allow the advance to come up to the maximum value, in this example 30°.

It’s more retard from the maximum advance than advance from a minimum value, because there is no minimum.

 

[PogoInTheWoods]

Still not advancing the timing which is physically fixed by the coil/flywheel relationship. Reducing the delay inherent in the design of the circuitry is what is actually happening. Advancing the timing in such a situation would require reorienting the flywheel on the crank so the magnets passed the coil earlier relative to the location of the piston in the cylinder BTDC.

 

[Sawrain]

I don’t feel I said what you disagreed with me on.

I said the maximum advance is set by the coil/flywheel alignment, i.e. physical position.

That the electronics can only delay (retard) ignition from this value, not advance.

Surely this discussion is just a simply a matter of ‘advance’ being a generic term used for ignition timing.

 

[PogoInTheWoods]

You're right. My bad. 'Maximum fixed advance to be achieved' pretty much covers it. The fact that 'advance' doesn't actually change on any type of dynamic basis is where the semantics can become cloudy trying to explain or understand it.

 

[huskyboy]

Yes, coils can advance/retard timing. At least some of the newer ones do in my experiences. A 372 and 390xp blue limited coils are a example. If you raise the idle speed too high the saw will actually surge a little as it goes in and out of advance. This seems to happen around 3,000-3,300 rpm when I measured with my tach. I usually set them at a tad below 3k to avoid this surging. Another example is the ms460/660 coil that retards the timing at low speed to make starting easier. The generic ms290/044/440 coil doesn’t have this feature and is more difficult to start. Especially after timing is advanced it tends to kick on half hearted pulls.

 

[Quzick]

That be damn Steve, they're going downhill!!

I've worked with 2 fresh 254 builds last week, they've won't complete comparative, timings & advanced timing is very close, will run them with 198 carb & mm's.
Got at least 3 different coils where all of them comes from the era where Husky advanced their timings, one of them is a Ducati coil.

I dit but a blue coil's from a 252rx on my 254xp and 262xp. (codes: old:537150001------->new:544018601)
starting the saw hot or cold is better, in my opinion.

 

[Stump Shot]

One thing always bothers me about coil advance. I just don't know about electronics but it seems to me that, The ignition can not advance timing. I can understand retarding electronically or holding the spark a little. This will definitely help on the starting and then the spark will go to the default position. I just can't understand how the ignition can anticipate when the magnets may be coming around and spark before the magnets excite the coil. If I am right about this shouldn't we be referring to a coil retarding and not advancing?

Un-retard = an Advance.

 

[beaglebriar]

Un-retard = an Advance.

Wish I could "advance" some of the folks I work with.

 

[SawJaws]

Yup, that's the one.

Thank you, Sir! I got it, one last question. Whats the proper air gap for this coil on the 390?

 

[Spike60]

.012/3mm

 

[Sawrain]

0.3mm, typing on phones .

Common business cards are 0.35 and 0.4mm.

Has anyone ever timed a saw to see what happens if you set it at double the spec distance wise?

 

[SawJaws]

.012/3mm

I had no idea these coils were being made in china, always thought they were produced in-house!
Is this a knock-off, should I send it back before I open it?




Got the coil from these guys...

 

[Tor R]

it probleby depend where the spark wire comes from, I would think a warehouse has them cut in 13" lenght.
With luck you get them as I did in one lenght (85")

 

[Lightning Performance]

395 coil swap?