I have three MVVS gas engines and they perform flawlesly, start easy, run reliable, frugall, and more powerfull than other engines on site of similar displacement, some people have problems some don't, it generally turns out to be self made problems and the engine gets the blame, most common problem is using a two pipe tank system and the one way valve in the feed tube not working correctly, using a three pipe system has eleviated more problems in this gas forum than I can count, next most common problem is using too low a voltage ignition battery, check the manual, next is dirt in the carb, filter fuel going into and out of your fuel carry container and put a felt clunk in the tank, that should be all thats needed, don't put another filter in the feed line its asking for another problem, next leaking fuel tubes allowing air into the system, the tubes from the tank need barbs on them to stop the tygon slipping off, zip tye the tube behind the barb, I use a soft wire wrapped around the tube and solder it onto the pipe (paper clip wire) don't forgett the tygon on the inside of the tank for the feed tube, barb and zip tye as well.

I am so satisfied with the MVVS engine's I am about to buy another, back up and service from Pe Reivers in Holland is the best I have ever had on anything in Aeromodelling, look on the MVVS Support Thread here on RCU and you will see what I mean.

Hope this gives a better ballance on the perceived opinions on gas engines and MVVS in particular. Incidently all of the problems listed above have been on all the different makes of gas engines, not isolated to one or another.

Mike