all my saitos 180 are mounted upside down,no problem,I strongly recomend the use of a "PERRY'oscillating fuel pump #vp-20(tower stock number #perg7000) $27.00 it keeps the fuel from getting in the carburator while the engine is no running,and keeps the engine from flaming out when on vertical and on idle ,also you can mount your fuel tank way back on the CG and the flow of fuel will be the same with a tank almost full or empty.all my engines use them and I have never had a flame out ,and that idle is so slow you can count the rpm almost just by looking at the prop.$27.00 for all that I think is a good deal.The installation is super easy and they are free maintenance.Also use an electronic glo driver,there are many on the market ,mine are made by JOMAR PRODUCTS (opto isolated glo driver)with your choice of radio connector,www.emsjomar.com tlf#800 845 8978 last time I bought one I think it was 40.00 this device keeps your glo plug hot while your engine is in idle.I love these two products and I can not even think in running my engines with out them.