I don't know the hp but I always found that mine was sufficient to run me through the pow in the Idaho mountains with no problem I still have the sled and put track cleats on it last year now you hammer it and the ski's lift off the ground no problem. my kids love to ride it but all my friends say it's real front heavy. as for the cutting out going up hill hoew steep is the hill? I would look at the float level in the carbs and also check you fuel pickup in the tank. the gas line to this seems to get real hard after a while you probably want to replace it and the weighted check valve on the end as well.