The post by 1cast1fish about the trim relay made me want to post this to possibly help someone who runs into the problem I had.

My 2005 Suzuki DF140 started sputtering while cruising on the water a few years ago. After it sputtered a couple times and wondering what the heck was going on, I turned around the next time it sputtered and noticed gray puff of smoke in the "exhaust". Since it is a 4 stroke motor, I knew there shouldn't be any smoke. I checked oil level and it was above the full mark on the dipstick. I took the boat out of the water and got on the internet searching for the problem. Turns out there is a low pressure fuel pump and a high pressure fuel pump on these motors. The low pressure fuel pump works with the camshaft and has a rubber diaphragm to pump fuel. Over the years of using ethanol fuel the rubber diaphragm deteriorated and let gasoline directly into the crankcase with the oil. This is called "making oil" which is why the oil was above the full level on the dipstick (my guess is there was at least a quart of gas in the oil). The gasoline had thinned out the oil so much that the oil was passing by the piston rings which is why there were puffs of smoke when the motor sputtered (the oil was burning). The low pressure fuel pump was around $30 and it took me 10 minutes to replace. After replacing the fuel pump, I changed the oil and filter. The oil was so thin that it shot straight out of the drain hole, past the drain pan and all over me LOL. Now I stand to the side when ever changing the oil :)