I run all my MDS and several other engines with rear needles and any problem with a remote mounted needle valve is imaginary, I even run Cline regulators at the carb and have the needle mounted at the rear of the engine. There is no problem. Also, as Sport suggests, you can purchase an add on remote needle, Horizon still has MDS remote needles, I use them because they do not leak when exposed to the 6 to ? lbs pressure when using crankcase pressure with the aforementioned Cline system. The Irvine and MVVS are both great engines especially the MVVS .77, same mounting as the MVVS .61.