ddmusser
Member
Hello all. Here is what I have going on. 1985 sundancer 300 with merc 260’s. For the first 1 1/2 hours the boat performs awesome at any throttle position. Then after 1 1/2 hours of continuous running, mostly cruising at 3200-3400 rpm’s the boat suddenly drops down to 3000 rpm’s on the starboard engine only. I shut it off wait 30-40 minutes and no issues. So, I have had a total tune up, distributor cap, plug wires, plugs, fuel water separators blah, blah, blah. Timing set, all complete. Motor has about 700 hours and is strong, it seems to be a heat issue, the mechanic has gone through all the cheap stuff first, says it has to be electrical. Has anyone experienced this gremlin before? My thoughts are: coil, cam module, or thunderbolt IV ignition, it only happens after about 1 1/2 hours of running, I know that at 3000rpms the timing goes full advance. So what could be causing this? Thanks in advance. Need some help.