Diesel Vapor Lock?

[Rob Sherrill]

Now that it's warming up in Florida my Yanmar has developed a weird way about itself. It seems to be "vapor lock" but as I am new to diesels I am not sure this is possible.What is occurring is that sometimes the engine will run rough and die. After bleeding the line, it starts again and runs fine. When I bleed the line it is "frothy" and once the air is out it is fine. I checked all my connections and they seem to be tight so I don't think that I am getting air in the line but it's possible.Any thoughts, suggestions, experiences with this sort of thing. Your comments and suggestions are welcome.ThanksRs

 

[Ed Schenck]

Couple of thoughts.

Make certain that your vent is clear. My vent hose had a low spot where fuel had accumulated. I was able to lift the hose to let it drain into the tank. Then I secured it with large nylon ties so that it no longer hung lower than the tank connection.Then there is the dreaded pickup screen. So I cut two cleanout ports into my 50 gal. aluminum tank because it was recommended that the screen be removed. Lo and behold, no screen! Just 22 years of gunk, actually very little but enough to occasionally block the pickup tube I guess. Yours may have that screen.Mine(H37C) also has a water separator ahead of the Racor. I dismantled that and took out the insides so that it can never be a problem. Good luck.

 

[John K Kudera]

Loose connection

I think there is a loose connection somewhere, or the copper washers have been tightened one too many times.Begin at the tank, check the hose, the fuel pump connections, and replace the copper washers in the fuel delivery system, a cheap fix? Don't forget the bleeder on the fuel filter. Another thought, is the fuel fresh? Water in the system somewhere?

 

[schaefer]

agree with john

i agree with john....rub your hand all over connections and smell for diesel....you'll find the leak..if not pump out all fuel or go to main filter first and check for water...good luck...schaefer