Started breaking in the engine last night, this is my first pumped 2stroker. Had a problem It just floods!!! Turning the low speed didn't seem to help. I replaced the diapram will try it when I get home from work. Also IT MAKES ALOT OF PRESSURE!!! should I be using some type of regulator?? Its a beautiful engine I plan on mounting it on a Laser Arrow delta I am using a MACS 1250 pipe and the final prop is goingto be a 9x9 APC

i had the same problem with mine, i had to turn in the diaphragm regulator valve screw a couple of turns in to keep it from loading up on idle ... You are using a check valve right?

Yes sir Iam using the check valve. what prop, pipe, and header length did you run?

I used the macs tunes pipe 1140....10x7 mas prop... from the glow plug to the apex of the tuned pipe was 12 inches

Thank you what kinda of RPM did it turn and with what fuel+glow plug

I have two NIB 45s that I have not run but I have run a couple of the YS 61s(the 45's larger cousin). They do develop a good bit of tank pressure. You will easily see the tank swell a bit under this pressure and when you are done running the engine and open the vent line to relieve the pressure, there is a noticeable amount of air that rushes out. This is normal.

about 14500 with 15% when i get a header for it im going to run a 10x6 to get more rpm