Hey guys. I have a '96 580 EXT EFI. Always keep the sled on a battery tender/charger. Sled runs good for awhile (an hour or so) then starts to bog down and dies. Let it set for 5 minutes or so to get it started back up but then will only get to around 4500 rpm set there and sputter and die out again. Put the sled back on the charger for a day and run it again the next day. Does the same thing runs good and then dies again. Charged the battery up and put a load test on it and it showed the battery was good, also changed the plugs. Any suggestions would be great. Thanks.