Fuel consumption

[David Stepney]

How do you tune a seven engine?

Tuning an engine in standard trim: Make sure that the points gap is properly set to 12 thou. Set timing. If you have a manual advance, the timing should be 20 degrees before TDC fully advanced. Automatic advance engines should (if memory serves me aright) be set to TDC stationary.

Check that compressions are even.

Start engine and let it warm up. Set the mixture so that the engine runs evenly. I use a Colortune (which is a transparent spark plug) to get the mixture right. The combustion should be a nice electric blue colour. Set the tickover to about 500 rpm.

My experience is with the side draft Zenith. Updraft carburetors may need more attention, but I am sure there are those with the required skills to tell you how it is done.

Hope this helps.