Part Seven: Carburation

[MustangMike]

Call me wrong if you want, but my Hybrid did real well in that hard cant at the Upstate NY GTG, I must have done something right with the tune!

My CFB likes it leaner than my MOFO, and they both have the same carbs. Must be different porting … or the 3 port muffler! Al likes to keep the front cover closed, the CFB has an aggressive dp cover. Stuff like that can change things.

 

[RI Chevy]

Hybrid and 460 are like comparing apples to brownies...
Lots of variables Mike. Not calling you out, just stating my observations.

 

[David Young]

Stuff like that can change things.

Wise quote here.

what rpm do you tune your saws to?

 

[MustangMike]

what rpm do you tune your saws to?

I don't know, I had some tachs, but they crapped out on me, and I just go by ear anyway.

Jeff, I was discussing both Hybrids, I have both a MOFO Hybrid and MOFO 460 (and CFB Hybrid). Ironically, the 460 is some of Al's older work and had both a 3 port muffler and bridge ports. It is also a D jug.

 

[MustangMike]

My MOFO 460 is my only saw that loved the HD-50 carb (461 carb). I can't explain why, I just know that it works.

I don't have one, but I'm wondering if anyone did comparison testing by running a 460 carb on a 461??? That would be interesting!

 

[RI Chevy]

Was the HD11 the 461 carb?

 

[MustangMike]

NO, HD-50, the HD-11 is the 70 jet carb.

 

[RI Chevy]

So the 461 has a smaller jet carb?

 

[huskyboy]

View attachment 211769

So the 461 has a smaller jet carb?

Yes

 

[RI Chevy]

Hmmm. I thought the HD11A came from 461 Artic. Interesting

 

[Wonkydonkey]

Hmmm. I thought the HD11A came from 461 Artic. Interesting

Remember, temp plays its part.. if it’s colder fuel does different things,, I guess that’s why it’s a bigger jet.

Btw.. if you look at the ipl. And cross ref the jets on carbs, you will get diff sizes for altitude as well as temps.(artics).. it’s a small difference but I guess the carb would not be able to tune right. Ie h jet screw just can’t feed enough or it’s fueling to much..remember3/4 -to 1 turn out Is About right ?
Porting requires more fuel and that’s why the jets get changed (enlarged) if they can’t supply enough fuel..

I'm not the best person to give good examples, but it’s a start..

Ps. I would ave to ask somebody with more expertise than myself if things would work.. and how large to go..etc.

 

[MustangMike]

No, it is a much older carb, 044 Artic is what you are thinking of.

 

[MustangMike]

The Artic carb also needed to generate a bit more power to heat the handle. Extra stuff running off the flywheel to generate the electric current.

My brother has a 460 Artic. Not sure what carb is in it.

 

[huskyboy]

The Artic carb also needed to generate a bit more power to heat the handle. Extra stuff running off the flywheel to generate the electric current.

My brother has a 460 Artic. Not sure what carb is in it.

The carb only has a heater element attached to it. The carb does not generate electricity. The generator behind the flywheel generates the electricity to heat the handles.

 

[MustangMike]

The carb is richer so the saw can generate more power … yes it is on the flywheel.

 

[huskyboy]

The carb is richer so the saw can generate more power … yes it is on the flywheel.

Mike, Julian proved already in his testing a arctic model generator doesn’t sap power from the saw. If anything, the heavier heated handles flywheel helps torque a tad vs a standard model. The richer carb is just a afterthought by stihl to allow adequate adjustment range in extreme cold if I had to guess. Not a power gain... your just less turns out on the screws, because the stock saw doesn’t need the extra fuel. Guys like the richer jetted carb for a ported saw because they need the extra fuel. Most heated saws have the same carb as the normal model... with just a heat pad element attached. Some don’t even have a heated carb, just a movable shutter to allow warm air in the air box. Which accomplishes the same thing.

 

[Fruecrue]

Good chart, but what it does not show is that with a chainsaw, a leaner mix can result in higher RPMs, which almost always results in more power.

The carb is richer so the saw can generate more power … yes it is on the flywheel.

Hi Mike! Hope all is well.

 

[MustangMike]

Sorry, but it is impossible to generate electricity from a saw (or from any source for that matter) w/o loosing a bit of power. If you could generate electric power w/o expending any energy, the planet would have been green a long time ago!

It may be very minor, and almost imperceptible, but you loose a bit of power. To say otherwise is to violate the laws of physics!

 

[huskyboy]

Sorry, but it is impossible to generate electricity from a saw (or from any source for that matter) w/o loosing a bit of power. If you could generate electric power w/o expending any energy, the planet would have been green a long time ago!

It may be very minor, and almost imperceptible, but you loose a bit of power. To say otherwise is to violate the laws of physics!

The heated saw is creating energy using something that is already spinning on a normal saw... the flywheel. If they lost power the specs would show a drop in horsepower between the heated model and non heated. If the saw engine was driving a separate alternator, then that would be different.

 

[Nutball]

But even something spinning will slow down if you suck power out of it, the engine has to make up for that lost power. The question is how many watts does the heater draw?