Originally Posted by
Cat 1
Very interesting project branch Bert... I think this could be very helpful it finding the set on those hard to tune conversions. I have noted a few times that these conversions have a wide band of acceptable "running" adjustments that will only show secondary issues in the form of dirty exhaust or running changes with Ambient and engine temps excursions to high our low. The ability to tune and observe actual mixture conditions is a very good capability.
On the item of the sample not being actually pumped - do you think one of the little air pumps I use for tank pressurization might be of use?
Indeed, The final finetuning in my plane engines were done by carefully observing the exhaust residue, but the issue with that would always be: "WHERE in the curve is that elusive rich spot that causes the black goo" ... I have so far always managed to spot it and remedy it, but at times it was VERY time consuming.
This way of tuning (running the engine through its throttle range while observing the measurement) COULD be of help here..
What is more: on "Non-Electronic" conversions, where the carb needs modification, the meter tells you where the fuel linearity goes.
In case of the small boat, the meter shows fairly conclusively that fuel supply rises at greater rate than air supply when the throttle is opened: CO percentage increases under load while compression pressure and combustion pressure go up (which in theory should make the combustion process more complete)
On the bolded: I agree with Dave, I think that is a VERY good idea...
I'll look into that.