Coil / Ingition Module

[double clutchin weasel]

Am I correct in thinking that a 544 04 71-01 "non-limited" ignition module would be a direct swap for the 510 11 49-01 "speed limited" unit on a new Husqvarna 390XP?

[nmurph]

I didn't look up the numbers you provided, but the coil from a 340-390 are the same, save a difference in the length of the lead. You can swap any of these coils back and forth and will provide the correct spark at the correct time. But be aware that the bottoms of a 390 may not like the rpm's you can get out of an unlimited coil. 13.5-14K rpm would be the max I would want out of that saw regardless of whether or not the saw was still four stroking.

[double clutchin weasel]

Thanks for the input.

Not really looking for more rpm. Just find it easier to set the carb mixture when you KNOW the mixture is limiting the rpm, not the rev limiter. When you're against the rev limiter, you can accidentally get the mixture too lean without hearing it or seeing it on the tach.

See where this is going?

Thanks again!

[Cut4fun]

I'm not looking your #'s up either. But black is unlimited and blue is rev-limited.

[nmurph]

Thanks for the input.

Not really looking for more rpm. Just find it easier to set the carb mixture when you KNOW the mixture is limiting the rpm, not the rev limiter. When you're against the rev limiter, you can accidentally get the mixture too lean without hearing it or seeing it on the tach.

See where this is going?

Thanks again!

Tune it rich and listen for the sound of the "miss" to change as it starts hitting the limiter- they are distinctly different.

If you saw is stock the factory carb settings will be close. They may be rich if you are at altitude, but that is better than tuning at high altitude and coming down the hill with your saw in the same tune.

[Cut4fun]

You will hear it and see it on the tach.
On the tach it will bounce around with different rpm's shown.  Hear it like a rev limiter on a race car setting at the tree missing.

[double clutchin weasel]

Wouldn't it have been much easier if the factory had set the rev limiter just a couple of hundred rpm above the "magic" number?

Trying to set the rpm via the mixture exactly the same as the rev limiter is touchy.

I usually end up a couple of hundred rpm rich...just to be safe.

Oh, and by the way, I've yet to see a factory carb setting on an epa saw that I would call "close!"

[double clutchin weasel]

I'm not looking your #'s up either. But black is unlimited and blue is rev-limited.

I had heard that before. Thanks for confirming it. I wasn't sure how many different coils there might be for the entire Husky line. Bolt patterns, wire lengths, flywheel diameters, etc...

Thanks again.

[nmurph]

Wouldn't it have been much easier if the factory had set the rev limiter just a couple of hundred rpm above the "magic" number?

Trying to set the rpm via the mixture exactly the same as the rev limiter is touchy.

I usually end up a couple of hundred rpm rich...just to be safe.

Oh, and by the way, I've yet to see a factory carb setting on an epa saw that I would call "close!"

I didn't say where the saw was set from the factory. The limiters are often set so that at the richest setting they are still shy of where the carb should be- 1&1. Pull the limiters and set the saw and you will be very close.

[bandmiller2]

Any clever rascal here know how to test a module off the saw. ?? Frank C.

[double clutchin weasel]

Wouldn't it have been much easier if the factory had set the rev limiter just a couple of hundred rpm above the "magic" number?

Trying to set the rpm via the mixture exactly the same as the rev limiter is touchy.

I usually end up a couple of hundred rpm rich...just to be safe.

Oh, and by the way, I've yet to see a factory carb setting on an epa saw that I would call "close!"

I didn't say where the saw was set from the factory. The limiters are often set so that at the richest setting they are still shy of where the carb should be- 1&1. Pull the limiters and set the saw and you will be very close.

Now you're singing from the right page!!!