I believe the perry pump you'd be looking at just requires crankcase pressure.

I have a moki 1.80 in a Dave Patrick Ultimate and it runs great without the aid of a pump. i run muffler pressure to the tank, that's about it. flying on an APC 18x8 prop.
If your Moki is new give it some time. Mine seemed to take some time to break in, but once it did it's been nothing but reliable.

Perhaps take a look at your tank and your clunk and make sure it's free to flop around inside the tank. Also make sure you don't have any pin holes in your fuel tubing, etc.