Many of you guys have offered suggestions to help me remedy my ongoing engine surge challenge. As a reminder...my fuel injected IO360 displays a very pronounced surge during idle and taxi following a flight and brief shutdown/restart. The problem never occurs when the engine iis cool.
I have tried suggestions such as ground running the engine at 1700 rpm for extended periods following a restart in an attempt to get some air moving through the cowl but that has resulted in limited success. So far my only remedy is to let the engine sit for a long enough period to let it cool significantly. If I do, I have zero issues with surging.
I even removed my fuel injector servo and sent it off for overhaul (not an inexpensive undertaking) as another attempt to remedy my problem. That idea does not address what I firmly believe to be the problem, heat causing fuel vapor lock, but I tried it anyway. I reinstalled the servo yesterday and test flew. The plane performed flawlessly as it always does following a first start. When I returned home and let it sit for 20 minutes, restarted and went to taxi, the surge was just as pronounced as ever.
All of my fuel lines are insulated and fire sleeved. The only exposed lines are the small lines that run up to the spider on the top of the engine. I do not have any fuel leaks. Turning on my electric fuel pump, while increasing fuel pressure from 20 to 25 psi, does not remedy the surge issue.
As posted here before I have taken the active and lifted off several times with this surge issue going on as the surge quits once I apply full throttle. As several of you have pointed out this is not a safe way to proceed therefore I am again asking for ideas/suggestions from you guys.
Many years ago in my drag racing days me and several of my friends would install a cooling can to cool down the fuel and therefore (we believed) helped us produce more power. We would use a coffee can, insert a coil of copper fuel line in the can, put this contraption in line (fuel line) fill it and fill it with ice prior to a run. While this is not a practical long term solution, is this the kind of thing I should be doing to prove/disprove my belief that I have a vapor lock issue?
I sincerely appreciate any and all suggestions!
Berni Breen
Lancair 360