Dead Cylinder AFTER Repair

[Russnrenea]

The primer line puts the fuel into the intake on the intake side of the valve. So a compression test will not show that leak.

We blew air through the intake system via the cylinder with the intake valve open and listened for air leakage into the case. During this test air was shooting out the primer plug line, but it is hidden by baffling and went unnoticed.

Russell

[riverbuggy]

primer nozzle location is upstream of the intake valve. In other words: "before the valve". It would never show up in a compression chk. The only way you could "hear" the leak is if you could pressurize the offending intake tube. The trick here is it would have to be that tube only, and that would be quite a trick.

[Mountain Doctor]

Thanks for the lesson gentlemen. That was a tricky diagnosis.

So, in effect, the cylinder was too lean for a combustable mixture? Is that why it did not make power (or heat)?

[aero101]

Seems like it would have been hard to prime due to no nozzle that cylinder and most of prime fuel would take path of least resistance, hard starting, and you'd have had fuel leaking as primed for starting? Oh well, glad to see you found problem.

[riverbuggy]

Yes Mountain Doctor. There would be no combustable mixture in the cyl. with the big air leak. Also all the other cyls. would be running lean at the same time. I'll bet that "3 cyl" test flight was quite a ride