how do you improve saw performance

[spudulike]

Agree with the sharp chain but if it is more POWER you want then typical tweaks are: -

Muffler mod - open up the outlet pipe to 3/4 of the exhaust port, take out any spark arrestor and drill more holes in the baffle plate

 

Open up the inlet and outlet ports - not for the amature

 

take out the base gasket and seal with liquid gasket - raises the compresion but check the squish

 

For further info go to the Arboristsite - full of useful info!

 

If you make any of the changes above, make sure you richen your mixture on the "H" screw by 1/4 turn or tune by ear so you can hear the four-stroking burbling at the top end of the revs

Spud

[lendahand]

not the 2 stroke mixture the actual air / fuel mix . when an engine is tuned i would expect it to run faster under load ie because it has more power but how do you set the mixture for a tuned engine because you wouldnt have the same airflow as a standard engine so the normal setting that were in the manual wouldnt be relevant or would they:confused1:

 

The fuel 2 stroke oil mix is critical and will affect performance, check the manual. As already said it's probably best to be shown how to do the tuning as if you get it wrong !!!!! new saw.

[lendahand]

Agree with the sharp chain but if it is more POWER you want then typical tweaks are: -

Muffler mod - open up the outlet pipe to 3/4 of the exhaust port, take out any spark arrestor and drill more holes in the baffle plate

 

Spud

 

You're braver than me, don't 2 stroke engines rely on backpressure to a certain degree?

[Magnus]

a saw running lean will tend to overrev. a tacho can tell you the engine revs which when compared with the manufacturer's maximum revs figure will let you know whether it is running rich or lean.

This is were many get it wrong!

 

If it is lean set it will be so regardless of Rpm.

 

Most who set the saws after rpm still don't get it right and get in trouble.

 

With saws today it is not easy to set by ear either as they have rev limiters that make it sound close to "fourstroking".

Setting saws after rpm is next up and work as long as there are no other issues.

But even if set after correct rpm they often want more to perform correctly.

When checking rpm there is a marginal of error that is to big and often lead to expencive damege and poor performance.

 

Best is to set after how it performs under load.

When it produce the most power under highest rpm.

 

It is not easy to set a saw and is best left up to those who know what they are doing or get the knowledge and do it.

Buying a tach will not teach how a saw is to be set it is just a tool to see rpms.

 

The saws work rpm/high rpm under load is set by a combination of three things: Porting, ignition timing and amount of fuel.

Edited October 22, 2010 by Magnus

[Magnus]

Any change made to engine require a bit of knowledge.

 

For example muffler mod... After this it breaths easier and needs to be readjusted.

If not it runs hot/lean and dameges come as sure as spam mail.

[Catweazle]

My 346xp has a Scott Wojo pipe on it, it flies but jeez is it noisy. No reliability issues so far, but I can't claim any credit for setting it up, it was all done by the bloke who I bought it from.

[Breezeblock]

i knowthat the 2 stroke mix is important but its the air/fuel mix i want to know about setting when you change the airflow in the engine:thumbup1:

[Magnus]

i knowthat the 2 stroke mix is important but its the air/fuel mix i want to know about setting when you change the airflow in the engine:thumbup1:

To set it as good as possible you start from the beginning.

Usually it is 1 turn out from seat (look up your specific carb on mfg's page).

 

Then you set L so it accelerated without hesitation.

H so that it "fourstrokes" on open throttle (No load but bar/chain mounted), but clears up under load.

T is idle. It should be steady in all positions and calm.

I should Idle for a 30 sek and still fly up in rpm.

 

After this it is warm and the fine tuning in work begins.

 

L and H affect each other so one changes both.

H is usually main inlet needle. Set this to lean and L won't get enough.

 

If it is tricky to set, dies suddenly, loose power, run on the way down in rpm, changes after half a tank, wonder up or down in rpm you have a problem to solve and start over.

 

Often there are problems that make you rebuild carb first, if not, make sure all parts in fuel system is clean and good.

[Yorkshireman]

in my experience its not the Saws fault

 

 

usually driver training ..... error

[ScottWojo]

Well, depends on your saw make and model. Most can be made to run better with a muffler enhancement and a better breathing air cleaner. The Stihl 044 046 and 066's can be fitted with a Max flow air cleaner. And some guy from eBay makes really nice muffler mods.