I have this engine on a pontton boat and the hour meter indicates 396 Hours. The engine idles a bit rough so I am wondering what I shoud check. Being a 4-stroke I never have rebuild the carbs, should I ? I think this engine is actually a Yamaha powerhead because Mercury did not have one ready yet. The engine has some stickers that indidate a valve adjustment spec. Do the valves need adjustment ? The engine starts and runs under power just fine. Being a pontoon it has been run at just above idle for most of the 396 hours. Is 396 hrs a lot ?
Thanks
Thanks