Vacuum and performance

[exSW]

A saw has to maintain a certain vacuum to run properly and not lean out. So does a significantly tighter saw run better?

 

[CR888]

You mean a saw that is worn has poor ring seal and decreased compression? Well yes, a good ring seal is important to make power. Or are you talking carbs as fuel delivery is a result of velocity through the venturi?

 

[exSW]

I'm not talking that specific. I just put together a 262. When I did the vac test it took a half hour to bleed down from 13 inches of vacuum. It runs very good. Since fuel delivery is a function of vacuum does better much better vacuum lead to much better fuel delivery?

 

[TJ the Chainsaw Mechanic]

The better the saw is sealed up the better it will run. Low/high compression will really affect how the saw runs as well. Not sure if More vacuum would help, but the amount probably increases some when the porting is done. Will say that the increased compression sure seems to help.

 

[Al Smith]

If you are talking a vacuum on the crankcase it can be assumed fuel flow is dependent on differential pressure .Goes from atmosphere to crankcase,crankcase to cylinder, cylinder to exhaust then back to wence it came,atmosphere .

Keep in mind though that static readings and dynamic conditions can vary .