i have 2 5.0 ford engines in a carver 310 yacht that im having trouble with. They are labeled volvo penta of course. it was initially running rough and narrowed the majority down to bad caps and rotors and ignition coils. quickest place to get coils was oreillys and the only ones they had were masterpro brand. initially they worked fine but then as the boat spent some time on the water the boat started running rough sync meter was out of whack and rpm gauges were dropping rpm. would do a hard bank one way or the other and the engine almost stall out. put one of the old coils back in and ran fine without a hitch all day pretty much. until putting back into the marina and would run rough and almost stall out. im going to get some motorcraft ignition coils in there to further get some other diags in there. no codes are present which is surprising after all this. its weird because it seems to switch to opposite engine like its sharing the problems that are occurring. i thought it may be a fueling issue when it would nearly stall out when banking hard but when the other coil was put back in it did not do that one time. trying to get some insight if possible on where to go next, im not a marine mechanic, a regular everyday auto tech that works on all things obd2 where i can read live data, this obd1 unit is a bit tougher to diag since i dont ever work on those vehicles.

 

I would try and get marine grade ignition parts in there even if aftermarket like Sierra. Change fuel filter unless you have recently done that. If fuel filters recently changed then unscrew then and dump contents into a glass jar to look for water or other contaminants. And reuse the filters unless you see a lot of contaminants.

 

hey thanks for the reply, i was actually looking at the sierra parts online before i posted in here but wasnt sure about them. the fuel filters were changed at the beginning of the season, like april'ish, im located in Minnesota. i'll dump them and see if there are any contaminants in there.
Thanks again, i figured we were on the same track.