Air leak - Racor 500 fuel fiter

There are lots of fun ways in which air can enter your fuel system - this was a new one to me:

The sailing yacht in the slip next to mine has the fuel tank built into the keel with the engine mounted above it. A Racor #500 primary filter is located level with the top of the engine. This is connected to the engine's lift pump. After running under load for a few minutes the engine would stop and could not be re-started using the plunger on the lift pump. The Racor filter would be half empty. There was plenty of fuel in the tank and the draw-tube was not blocked.

Here's what it turned out to be. This is the opposite of a gravity-fed system: the lift-pump sucks fuel from the tank through the Racor, thus the Racor is under vacuum and air will enter anywhere it can. In this case the little O-ring (green arrow) had become hard with age and was no longer making a good seal. A tiny stream of bubbles could be seen rising through the fuel in the bowl.

My own Racor drain valves look like the one on the left which use a different type of seal (pink arrow). IMHO, the one on the right is a nicer piece of engineering.

That is a common problem on racor filters, and the stream of bubbles is a dead give away. I much prefer the Davco filter setup used on big trucks, its vastly superior to racors and filters are much cheaper and easier to get. Any auto parts store or truck stop has them. They also have the added benifit of showing when the filter needs changed due to the inherent design of the unit.

>I much prefer the Davco filter setup used on big trucks,<

And priming is really easy as its simply poured in the top .

Sadly they do not have a $1.00 SS bowl to pass as marine units , so your insurer may not like them , and a surveyor may try to earn his fee by noticing.

FF said:

>I much prefer the Davco filter setup used on big trucks,<

And priming is really easy as its simply poured in the top .

Sadly they do not have a $1.00 SS bowl to pass as marine units , so your insurer may not like them , and a surveyor may try to earn his fee by noticing.

Click to expand...

Here we go again.....A un-inspected boat is not required to have the SS heat shields.