The only gage that works currently is the speedometer. The boat starts and runs well but every now and then, after slowing down I try to take it back up to a faster speed and can only get about 10-15 mph. When this happens I bring the boat back to an idle/turn it off for seconds and restart, and all is well again. It runs about 35mph. I've had it out twice and this has happened about 6 times. Suggestions on where to look first?