ORIGINAL: dbateman
No success on forth try yesterday. All this talk about easier than piston engines is nonsense.
That's a pity Doug. Once I got the gas warmed up and shaken up, and ignored Wren's instruction to hold the starter on all the time, I always quickly got up to temp and the fuel flowed. The problem was not having no flame, the problem was far too much and getting many shut downs due to the flames coming out the back hitting over 800C and the engine shutting down automatically. No doubt that's why Wren want the starter on full-time, but when I did that then many times it did not get to minimum ramp temp. In fact on several occasions the starter blew out the gas flame, when I switched the motor off and the engine wound down enough the gas would relight. Having had that a few times was what made me decide to try blipping it and that got it to the fuel stage, but you have to be so careful not to get a fire at the back end, hence my advice to be back on the starter immediately the fuel ramp is indicated, or a degree or so before that point.
What rpm range were you blipping it at? What temp was the gas in the bottle at? You used propane? Does butane burn hotter? I used a butane propane mix approx 70:30. My full auto-start PST has the same problem as the manual start MW44 if the gas is not warm and shaken, it sits stubbornly well below fuel ramp temp, and it seems to have a speed controlled motor while awaiting the fuel ramp so it doesn't keep accelerating like the MW44. Getting the gas bottle thoroughly warm, then giving it a good shake, is
essential to getting the gas stage up to temp. Until that bit is sorted, it's hard to lay any blame on the engine or starting technique.