My 1983 universal M15 diesel acts up every once in a while. Just brought a 27 Catalina, know how to sail but Diesel engines are new to me. She seems to run fine most of the time. I use the engine for about 15 minutes to reach open water and return back to the dock on a lake. Out of the 20 times she has ran she runs fine. But about 4 times she starts fine for about couple of minutes then seems to lower the RPMs. Than revs back up than down almost stalling, but never stalls. Revs back up & down. We reach our destination ok but worry she'll cut out totally. We maybe on our way out, put up the sails, sail for a couple of hours, head back to the marina and the engine works fine. After it happened the first couple of times I completed a much needed oil change thinking that could be the issue. The engine sounded and ran much better after the new oil and filter. I've ran the engine three times since the oil change and it happened again on the way into the cove. The fuel tank had about 3 gallons when I bought her. I put another 5 gallons of diesel. (Not sure how old the deisel was that was in the tank. Am thinking the previous owner may have put in fuel for our suvery, as the boat was not run and on the hard since last fall.)Thinking I would use that much fuel before the season here I Maine ends. The engine does not have a water separator yet. It was on the suvery to install one. A winter or spring project. Any suggestions you can offer would be appreciated. Thank you
