I have a 1984 O'Day 30 with a Universal diesel M-18. Engine was running OK for 15-20 minutes and then engine alarm would "hum" for 10-15 minutes before coming on fully. While the alarm buzzer is sounding, my engine is not running hot. I have replaced the audible/visual alarm, thanks to Torreson Marine, and I also needed to replace an in-line fuse when the engine would not start after replacing the alarm. Now engine turns over, although sluggish, but the alarm kicks on immediately. Finding a diesel mechanic has been next to impossible. Any suggestions on trouble-shooting this situation would be appreciated.