RE: 90SP Muffler failure on run #4.
I have no idea what the trick is.... but the thing will idle so low that the prop blades can be clearly seen swinging around. LOL! It has a very scale-like idle.
The lowest idle I have on it so far is 1450 rpm according to my optical tach, swinging the MA 18x12 2-blade break-in prop. That's without the glow on. I've let it idle that low for up to 5 minutes at a time without any sign of loading up, and it transitions right back to wide open throttle without hesitation. Could be my location, since I'm only about 30 feet above sea level here in Houston Texas. Also I've been running only CoolPower 10% full-synthetic fuel in it since day one. The engine looks and feels just as nice as it did the day I 1st took it out of the box (aboutg a year ago to date). I highly recommend this fuel for this engine!
The replacement muffler has held up very well I'd like to add... much better design than the original muffler it came with that was falling apart.
Regards!
- Michael