Auto Tune….

By Tim Ard, Forest Applications Training, Inc.

Manufacturers have been talking about it for a while but it might be just in time to help curb some (not all) of the fuel issues with ethanol base gasoline. Husqvarna has introduced a new version of the 576xp saw with a new Auto Tune carburetor. It’s not really a fuel injection system but it is a smart carburetor that’s a very close twin. No manual adjustments, the carburetor makes automatic adjustments of the fuel and air ration going into the engine with an electronic control system. It also compensates for air filter obstruction to help minimize rich runs and loss of power.

This Auto Tune system should help some with the issues around ethanol fuel supplies. Ethanol added fuels have a larger molecule to transport and also attracts moisture (water) at the molecule so it in effect requires a larger hole (carburetor jetting) to offer enough fuel to maintain power and RPM control of your saw. Some carburetors today do not have sufficient adjustment capabilities to handle the larger ethanol fuel structure.

Take for example if you have a saw adjusted to spec, at less say 13,000 rpm. The engine is running great and you have plenty of lubrication taking place because you have a proper oil to gas mix ratio adjusting in. It’s all good….

Now you buy fresh gas at a local station and mix in your oil to requirements. The new fuel you purchased however has 10% or more ethanol in its formulation. If you do not change the carburetor adjustments of air and fuel entering your engine you have most likely leaned out the run of the saw because of the added fuel flow requirement of the ethanol, which you are not getting, and also your lubrication is minimized because of this fuel restriction. Leaning the lubrication and over speeding the design. Not good….

The Auto Tune carburetor will now step in to do its job. It allows more fuel in to properly mix with the air through the filter and voila – proper running engine. The only thing to consider now with the ethanol fuel is the water accumulation and the deteriorating effects on your saws rubber and internal parts. Which these effects are somewhat minimal to the seizure costs.

I hope we see many more of these techno changes in the near future and even some upgrade carburetors available for existing equipment – that would be nice. This would correct a great deal of the run problems showing up in the field. Until then – seek out a source for TruFuel or a gas without ethanol to do your mixing… or I recon you could just buy a new Husqvarna 576xp.

Good Sawing,

Tim Ard

http://www.husqvarna.com/us/homeowner/products/chainsaws/576-xp-w-autotune/