Hi - I've recently upgraded to a 30' 1982 O'Day from a 25'Catalina & we're new to having to deal with a diesel as opposed to the olde relaible outboard on the Catalina. We have been having some "fuel issues". When idling we have no problem but when we are out and throttled the motor up we have seen the motor "die" after about 5 minutes or so. My question here specificially revolves around the fuel venting hose. I removed the hose from its connection and found that it contained probably an ounce of "liquid", perhaps a mixture of olde diesel and or water. I removed the thru-hull fitting and found the two little screened venting holes to be about 90 - 95% clogged. I could barely blow any air thru them. After a thorough cleaning air was flowing freely. As we throttle up the motor we suck fuel from the tank, if air does not replace this fuel to equalize the pressure in the tank could this be one possibility of the motor dying?? As we are also treating the current fuel for possible algae and have also had it vacuumed, we are wondering what the likelihood of this vent hose being the problem after all. We have not been out for a sail since after cleaning the vent hose but we will give her a try tomorrow during Cleveland Race Week. Any thoughts???