YS 1.40L sensitive needle
I have a YS 1.40L that was sent for a through refurbishment due to sitting on the shelf for over a year. They changed the plunger and spring in the regulator, and instaslled a new piston ring, then test ran the engine. I installed it in a patriot with a new crank tank, and new fuel tubing. The plumbing is connected properly and the check valve is testing good (it holds pressure, no leaks). The engine gave me trouble and I replaced the diaphram in the pump, the old one seeming stiff. I managed to get the engine running and flew it a few times, but the needle valve is so sensitive it goes from blubbering rich to over lean and sagging in 2 clicks of the needle valve. The regulator was set at flush with the housing to start. I tried to lower the regulator pressure setting 1/4 turn but needle sensitivity is still the same. I am running 30% nitro, 20% oil helicopter fuel.
Anyone run into this issue? Any suggestion to correct the problem?