My 2002 135 Optimax (SN 0T701655) has developed an issue, whereupon starting cold it will rev to 2500 - 3000 with a good puff of smoke, than die. On the second start, it will rev up again, but not nearly as high, whereupon it may die or continue to run. If it does die, the third startup typically doesn't cause a rev up. Once running, the motor has a stumble / cough / miss every 3-4 seconds. Once off idle, that cough seems to go away. Digging into my service manual and these boards, basic symptoms without any testing point towards the fuel regulator diaphragm. Tracker is my second guess, but hard to pin point without pressure readings yet. Is there anything else that jumps out?
I will take pressure readings this weekend at idle / 5 / 10 / 15 seconds after and post the results. Are there any other good ways to test for leaks on the fuel diaphragm / tracker valve? Can I pressurize air side to 80psi, turn key to on to run the pumps, and monitor the fuel pressure leak down? Would that definitely show any breaches? My motor is one of the earlier models that does dump the air pressure 100% at shutdown. Are there any other tests / things I should check while doing pressure checks?
I posted a video to Youtube of the stumble as well - link is below. Engine runs only DFI oil. I also rebuilt the pulse fuel pump earlier in the summer when I replaced the three year old fuel lines.
Thanks for the help!
https://youtu.be/6YfAuhLdxys
Josh