Re: Universal M18 Power Loss
Do you start getting any smoke when this happens? If so, what color?
Otherwise, you are most likely experiencing an issue that causes less fuel delivery. On sailboats, a common culprit is plugged fuel filters. When they start to plug, the engine will run fine at lower throttle but won't have power on the top end. This situation does not fix itself so you should notice it regardless of how long the engine has run. Similar to plugged fuel filters is a plugged pickup in the tank or a plugged tank vent line. The vent line will fix itself if you loosen the fuel fill so it is easy to check. Another common one is that the fuel shutdown will slowly vibrate so that it is pulled out just enough to cause a loss of power. I have experienced this on several boats and it is not a big deal because you just push it back in. It is unlikely that you have a heat related issue as your engine has been running at steady state for many hours but it would be worth checking your temp gauge when this happens. There are other possibilities but these are the ones that I would start with.