O.T. tach for chainsaw?

I use the trigger..... ;-)

Seriously, that is WOT where it normally runs. It is normally either at idle or wide open when running. Any half throttle cuts are usually rare....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

FrankW wrote:

If you run it lean, it will just stop until it cools down.

I prefer to start rich and bring them lean. I find it pretty easy to hear the difference when it leans out smooth. Too lean and it will miss. Does the book say to lean it until it misses and then make it rich so many turns?

Mike

FrankW wrote:

You'd need something like this:

But since you probably don't have one of those or can justify the price, you can probably do the following:

At WOT, keep turning the high speed jet richer until the saw "four-cycles".

This is a distinctive sound that a 2-cycle engine makes when it is running too rich. You'll know it when you hear it.

Then, turn the high speed jet leaner until the "four-cycle" sound just goes away.

Or just stop by a local small engine shop. They probably have a tach like the one mentioned above and would probably be willing to adjust the carb for you for nothing, or perhaps a beer...

:)

-John

LMAO!

Hey!!!!!!! It's not supposed to be funny

Well actually, yes it is. ;-) Cheers Frank

Kate wrote:

A small engine shop will use a wireless tach to set the main mixture - you can buy either a digital or analog unit and just hold it near the engine to pick up the sound impulses. It is a very quick and accurate way to set the mixture. If you decide to get a digital tach, get one that updates the reading frequently - some take more than 2 seconds to change readings and that is not good.

Here is one I found with a Google search:

You do NOT want to mount a tach permanently on your chainsaw, since it will self destruct from vibration.

It is simple enough to set the mixture by ear - run the warmed up saw at WOT and slowly turn the main mixture screw towards rich. The saw will start to slow and eventually will blubber (4 stroke). Turn the mixture towards lean and it will pick up and start to run clean. It is very hard to tell 10K from 11 K rpm by ear - just play with the setting a little at a time until you find a setting where the saw cuts well without bogging down. If it seems to lack power, lean it out a little more (no more than 1/8 turn at a time).

ALWAYS err on the rich side - running lean can seize the piston!

If this doesn't make sense. take the saw to a shop and watch them set it - then you can duplicate the process.

John Davies Spokane WA

Been using one for years

Coasty did pass the time by typing:

Couldn't you just use a regular engine rpm gauge on the spark wire and multiply the result?

I just tune mine by ear.

Must have a calibrated ear + or -

Coasty did pass the time by typing:

:) sorta. I'm fairly good at detecting pitch.

Then again, chainsaws arn't rocket science or NASA could make them blow up.