That's a very heavy prop you got there. You should check out some nice light weight wood props like Bambula or Menz. I run a Bambula 20x8 at about 7200 RPM on my Moki 2.10. The Bambula has much bigger paddles than the APC hence the lower diameter prop turning the same RPM. The lighter wood props will spool up much faster than the APC. Try one out, you might like it.
P.S. that's a sweet looking YAK.
ORIGINAL: katipo
Well I ran a little over 2 24oz tanks through my Moki with the Pitts muffler. No complaints and very happy.
I now have it on a MACs quiet pipe and wow! It's now swinging an APC 22x8 at 7200rpm.
From what everyone has said it still has a lot more running in to go.
I've got it in an 87" EF Yak 54.
The pic below is with the Pitts muffler.