First time poster here. I've read a lot of the post but havent seen anything that sounds like the problem I have. I got a 90 hp engine on a 21 ft pontoon. When I run over 3000 rpm the engine jolts intermittingly almost like I"m hitting something with the lower unit. There is no cadence to the jolting but happens every 20 or 30 seconds or so. The tach does not increase or decrease. Ive changed the prop and its running 5200 at wide open throttle. Just another note, The back of the boat sits pretty low in the water. There is no water in the toons. Not sure if this has anything do with it. Anybody know what is causing this? I have no clue and the boat doesnt get used much. Thanks in advance
