I have a brand new DLE 35 currantly installed in a Lanier giant scale Taylorcraft. I am new to gas engines and have had a fair amount of problems getting it started. After consulting the instruction manual and following the necessary instructions I finally got the engine started with the cowel removed. It ran a bit rough at first then it smoothed out. It ran for approx 7 min then as I quickly advanced the throttle it began running with a quick miss fire, brbrbrbrbrbrbrbrbr. This condition persisted at both high and low throttle but When I eventualy slowed to idle it cleaned up and ran smoothly. I am using a 4.8v 2300mha NMH 5c battery for ignition. When I checked the battery it had dropped to 4v from being fully charged after running for 7 min. My gas oil mix is 30-1 using 91 octane fuel and I have a 16oz fuel tank. Acctualy there was slightly more oil in the fuel but no smoking was detected. I checked all connections and all seem good. Would a voltage drop in the ignition battery cause it to missfire at a higher rpm? Should I be using a higher voltage battery? The manual says a higher volt battery is acceptable. I also noticed that the bolts mounting the engine to the stand offs had started to come loose, one acctually coming off. Two of the three remaing bolts were still tight. Bolts were tightened prior to start but I forgot to use locktite, valuable lesson learned here. Could loose bolts have caused the missfire? I'm scratching my head here, any help would be appreciated.