1200gpr dropping cylinder

[yukon570]

i have a 1200 limited gpr that i bought as a basket case. rebuilt crank and rear cylinder. Put back together and noticed the converter was broken and turned sidways in pipe. Removed converter and added the plate with chip for computer. starts and runs fine on hose, took to lake and takes off like mormal running great but as soon as I get about 500 ft out it drops the rear cylinder. not quite sure if its dropping spark or if its a fuel issue. seems like after it sits, it will fire up and run on all 3 again until you take off and start going then it drops rear cylinder again. I also get a bunch of beeping from the machine

[Technical Support]

Re: 1200gpr dropping cylinder

Could be a coil thats failing if its loosing spark. If its fuel related then go back through the carb.