Just passing on what both the manual and owners of the store said.
A lot of reading of installs and reviews...these tiny fuel pumps can be very finicky.
When my Wallas was having issues....the company replaced a pump under warranty even though it turned out not to be the problem.
That is how low their confidence in them is so I reigned my fuel supply and filters to spec just to be sure.
Hi Psneeld-
Was down at the boat the other day and as a result of this thread, began to check out the Wallas system. I inspected the fuel filter, a very small unit inline installed. It appeared clear and I use #2 diesel. Still, having a spare filter other than the one I do have, in house seems a good cause so I called the Wallas dealer (By the way- who is your dealer? Asked as I was under the impression that "Sure Marine" in Seattle was the National distributor. Do you have a different source?)
Doug, the brother of the two who own Sure Marine, advised that replacement of a filter was a many years before need issue. Said the micron is 9 or very porous in terms of micron levels.
In conclusion, fuel supply of #2 diesel directly teed off the main fuel line into the DT30 carburetor. The fuel line in reality is a horizontal run with no ups or downs for the 10 foot run.
How does that stack up with your history?
Regards,
Al