daveb Posted January 17, 2007 Share Posted January 17, 2007 Hi everyone. I need some help with my 720. For the most part it runs well except the occasional backfire (through exhaust) when you turn it off. But when it gets cold out it will "loose a cyl." only rinning on one .If I pull the head off and clean it and put it back on it seems ok for a while. Any advice will be greatly appreciated. Thanks Dave Link to comment Share on other sites More sharing options...
D-17_Dave Posted January 17, 2007 Share Posted January 17, 2007 Simular to the other post on a CCK engines it sounds as if the valves are giveing you trouble. The valve guides wear hard on these engines and will cause the valve to droop and not close correctly and smoothly. I would first check the lifter adjustment and try richening the carb jets a little as a lean mixture will heat the combustion chambers and especially the exhaust valves. If you have the head off then open the valves and check for side play. Link to comment Share on other sites More sharing options...
JimS Posted January 18, 2007 Share Posted January 18, 2007 What brand of plug do you have? I have had similar problems with Champion plugs fouling if the tractor is not used very hard. You can pull the plug wire away from the plug to create a larger spark gap and sometimes this will fire a fouled plug. Link to comment Share on other sites More sharing options...
daveb Posted January 19, 2007 Author Share Posted January 19, 2007 Thanks for the info. Dave I will check the valves when the weather breaks .We finally have gotten some cold weather but still very little snow. Jim I'm using autolite plugs. I was able to get to run on both cyl. by removing plug wire and making it ark. The tractor only has 670 hours on it, the cyl. drops when starting so it only starts on one cyl.Was thinking maybe head bolts are stretched. Thanks again . Dave Link to comment Share on other sites More sharing options...
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