Perky's Perplexity Part 3

Hey all!  We've just arrived in Mazatlan after a 36 hour passage across the Sea of Cortez.  We had very nice weather for the crossing and at mid-point, were a whopping 90 miles away from the nearest land!  Unfortunately, the waters off Mazatlan just can't compare with those off La Paz and the neighboring islands.  The pic above was taken at Isla Espiritu Santos.  April's update will soon follow with more pics!

Okay, I'm going to give a quick update to the diesel jockeys out there regarding the engine troubles.  Yes, we're still having them - but I think we're closing in on the perpetrator.

Since our last visit, I've replaced the lift pump - pretty straightforward.   Afterwards, I measured the rate of return fuel flow at various engine speeds - both in gear, and in neutral.  Regardless of engine load or RPM, the return fuel flow rate was identical at 250 mL in 2 minutes, 35 seconds.  My apologies for April for destroying her nice silicone measuring flask.  No matter how hard I tried, I couldn't scrub the diesel smell from the flask.  I think she is silently protesting because she hasn't baked a loaf of her delicious cinnamon walnut bread since!

That last test was done at the suggestion of Tom Davison.  We both believe that we have now verified that everything in the fuel supply up to (but not including) the high-pressure injection pump is working fine.  I also pulled off the rigid fuel lines running between the secondary fuel filter and the injection pump to verify that the line was clean.  It was.

I addition, I dragged myself behind the boat at 6 knots (nearly lost my trunks on that one) to watch the Max prop in action.  In both forward, neutral and reverse gear, the prop feathered easily and spun freely.  The blade pitch has not been changed since we bought the boat in July.  I know many of you have suggested it, but please believe me - as God as my witness, IT'S NOT THE PROP!  Sorry, I had to get that out of my system.

Shortly after arriving in Mazatlan today, we pulled alongside the fuel dock and took on fuel in both tanks.  This time, I used a pre-filter (purchased from West Marine back in Cali) before pouring any suspicious Mexi fuel into our tanks.  Knowing how much fuel it took to top off the tanks, and dividing that number by the engine hours run, I calculated a fuel consumption rate.  And the number is......  0.75 gallons per hour.  This is a significantly lower rate of fuel consumption than we experienced during our trip south from San Diego (before the engine problem started).  Back then, it was slightly over 1.1 gallons per hour.

I think this confirms that the engine is not getting enough fuel!  And the only thing left on the supply side that we haven't touched is the Injection Pump and the Governor.  My money is on the injection pump.  Now all we have to do is get our hands on one and change it out.  This will not be a trivial project given the cramped nature of the engine compartment, but I'm sure that we'll manage.

Until then, thanks for all of your suggestions and good wishes.  We miss all of you and will post again soon!

Peace.

John