I’ve heard that using the NGK type “V” plugs are the best for checking jetting. What about it?
When using the “V” plugs, the tip of the electrode is an excellent indicator of the fuel air mix. The tip should have a silver appearance about 1/3 of the way down. If no silver is showing, or silver shows only at the edge of the tip, it’s running rich, silver past the 1/3 point means it’s lean. The only real way to know how safe you are at partial throttle is to be watching the EGT. You could make a mid range (like half throttle) run for a 1/2 mile and hit the kill switch while holding the throttle constant. When she stops pull the plugs and see what the tips look like. Do the same on a lake with a WOT run for 1/2 mile or more, hit the kill switch while keeping the throttle position constant. This is the most accurate way to check plugs if you don’t have an EGT. I am convinced an EGT set up is the way to go for those looking for that edge. Good probes with an analog gauge work fine, but the digital units provide the best accuracy and are easier to read.