Installed Non limiting coil on 372XP; any tricks?

[Engineeringnerd]

I bought a non-limiting coil for my 2004 372XP from a boned 371XP on ebay for $25 + $5 shipping after determining my local dealer didn't have any to sell. I've only done a muffler mod on my saw, but I don't like the limiting function. It makes adjustments really tricky, and I like to tune by sound and verify by tach.

I installed the used coils without any problems and used a piece of paper card (roughly 0.018" thick) to gap the coil from the flywheel where the magnets are located.

It cranks and runs fine and I helped a buddy cut up a big pine with it. Any reason I should change anything or gap it to some specific measurement? I didn't have any instructions, so I pulled a trick from of my youth when I used to work with Briggs and Stratton lawnmowers.

 

[frankyslog]

in regards to coil

you stated you are running the non limited coil. if your doing it for more rpm be cautious . taking into consideration existing wear, within your saws low end. crank balance , bearing wear ect, ive had guys show up at my work bench who have done this for (rpm gains) and ended up envoking on the laws of diminishing returns, or in a couple of cases with a crank shaft with weights that were severly out of phase! damaged bearings ect!crank case harmonics drastically vary depending,on crank trueness,bearing wear,ect. congradulations on your parts find, a buisness cars is a place to start but no replacement for a feeler guage. good luck

 

[Engineeringnerd]

Frank,

I'm not looking for the rpm gain, I just find the limiting coil difficult to tune between rich and lean. It "4-cycles" on both sides of optimum.

Any idea of the correct gap? I have gauges but I don't have specifications.

 

[timberwolf]

I think the rev limited coil can cause more damage than good. It is realy near impossible to tune the saw right so it ends up runing too lean and sitting on the rev limiter, or too rich and turns the pistontop into a charcole briquette.

Saw will be fine tuned right and running at 14,000 or there abouts. I found the timing on the non rev limited coil to be a little retarded compaired to the rev limited coil, maybe just variation one coil to the next, but the saw actually cut a little faster in bigger wood with the rev limited coil.

 

[troutfisher]

I didn't know 372's came with a rev limit coil.......What years apply and what is the rev limit?

 

[Engineeringnerd]

I believe it started in late '03, or early '04 and limits @ 13,600. Most of the limited coils are blue in color, non-limited are black.

 

[troutfisher]

so, as long as I'm setting the carb below 13,600 it will sound normal? say, 12,500 rpm......it will 4 stroke and tach as if the rev limit was not there?

 

[timberwolf]

Yup, and it will cut like crap and carbon up real good, not to mention spew raw fuel for no gain.

Getting rid of the rev limited coil is a good move.

If I were to use a saw with a rev limiter, I think I would want to set it for best cut time and them maybe back it off a hair just to be safe.

 

[Engineeringnerd]

My 372 has a pretty open muffler mod, and I don't know how others run. With the rev limiting in place I found that it was just starting find it's sweet spot around 13,200 or so, but suddenly jumps to the limiting zone from 13,000. It really wants to run a little over 13,500.

I found the saw was constantly running a little out of kilter when cold, when the filter was a little dirty..... the running band allowed by the limiter was too narrow for reality IMO.

I'll probably set it around 13,600 and allow it to vary a little for normal variables.

 

[bwalker]

I have a 04 with a black coil. It appears there was no cutoff point when the non limited coil stopped being used, rather it was phased in gradually.
The business card trick has always worked for me, but the proper way to do it is with a proper set of gauges.
FWIW I have found a stock, but muffler modded 372 runs best at just under 14000 in most cases.

 

[Engineeringnerd]

FWIW I have found a stock, but muffler modded 372 runs best at just under 14000 in most cases.

Thanks, that confirms where I think my machine is heading. I tell you, setting the carb is tough on these machines. It's really hard to adjust while the saw is running, and I hate to rev it for too long while I'm trying to reestablish the position of the driver on the screw head. The adjust at idle, then rev, adjust-rev-adjust-rev thing doesn't seem to work well for me.

I'm perplexed why Husky can't put good sized carb screw heads near the exterior of the saw like Mac did for years. I can adjust my EB 3.7 with my eyes closed (and given the way it looks now, that's a good thing!).

 

[frankyslog]

hard to tune !

i agree these are very fustrating to tune! with needles, positioning ect. ive got a base line muffler, that i fabed together that i install on my customers saws. for tuning purpose, with air fuel ratio bung port welded in place, for monitoring purpose.with total exit volume increased 30% over stock. seems to work well for up to stage 2 true work port, motors used in conjunction with tach. gets me where i wana be at,with a particular motor.saw mounted in vice of course. ive got a couple of aluminum spacers to help with matching port to muffler for tuning a stock or improved stock cylender.

 

[frankyslog]

what time is it?

i certainly agree with timber wolf in regards to rev limited motors while lugging in wood, (heat soaked motor) pull harder with stock cylender, they husky r/d obviously matched the stock port timing, up to this timeing curve for max (bsrt) brake specific reserve torque , on tap

 

[hornett22]

coil to flywheel air gap should be..............

0.3 mm

 

[bwalker]

I found the timing on the non rev limited coil to be a little retarded compaired to the rev limited coil, maybe just variation one coil to the next, but the saw actually cut a little faster in bigger wood with the rev limited coil.

There are at least a half dozen coils that where made for the 372 over the years.
Maybe the best ones to get are the newest non rev limited ones?
With that said I had three 372's at one time and the fastest one was a 03 non rev limited model. The other two saws where a non rev limited 04 and a 04 with a rev limiter

 

[Engineeringnerd]

The non-limited coil I just installed was an '03 from a 371 supposedly. I didn't know the 371 went that late, but that's what the seller said. The part is stamped 03.

I hope it works well!

 

[SWE#Kipp]

I got a 371 coil in my -06 372xpg and it works fine
easier to find top rpm after it was installed !!!

 

[bwalker]

03 from a 371 supposedly

The 371 was discontinued well before 03.

 

[Freakingstang]

going off of memory, 98 was the last production year for the 371, but I have seen a few 99 models out there as well. I haven't checked the differences in the timing of the coils, but the 371's seemed a lot stronger to me than the 372's. Of coarse, the one ring models probably had a slight advantage

 

[Engineeringnerd]

Yeah, I think '03 is wrong for a 371. He probably meant to say the coil would work on a 371 or 372. In any case, the coil I have seems to work fine.