Understanding Diaphragm Carburetors

[Terry Syd]

I had a private email asking about concepts relating to diaphragm carbs. I recommended reading this document - http://www.mikuni.com/pdf/sbn_manual.pdf

It is the ONLY document I found that didn't contain heaps of errors. The Mikuni carb is more sophisticated that the diaphragm carbs we have on chainsaws, but the manual explains the concepts of tuning very well. I wish we had the adjustment on saw carbs that the Mikuni does.

 

[Terry Syd]

The Mikuni manual is a good source of information on diaphragm carbs. The Mikuni is used for boat racing and one of the things of prime importance is throttle response and torque coming out of a turn. Of course, we don't have to worry about something like that on a saw, however the manual spends some time discussing how to use different jets and springs to achieve the desired results. It is those in depth discussions that reveal how the diaphragm carb is designed to work.

If someone has a question about diaphragm carbs, we can discuss it using the Mikuni manual as a reference point.