Racor fuel filter with air in bowl

Newsgroups Archive Prior to 2025
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Ok old wise and wizened ones;

My Racor fuel filter appears to be collecting air. The fuel level is almost down to the bottom of the filter.

It’s one of the filters with the clear bowl and push-on filters. It has a flattish disk on the top with stainless band that holds top to bowl.

I’d guess that if the engine starts sucking air in the fuel line, that’ll not be a good thing.

How to clear it, and keep it clear? Just add diesel and close the top?

Any words from those with experience with this filter? I’m always trying to learn from those with more experience than I.

Thanks;
John, NS26C Kingston ON.

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We had a similar problem with our Racor Filter. It took a couple of years to resolve. The problem turned out to be the valve at the top of the tank. Since the fuel pump pulls fuel from the tank the pressure at the valve is less than atmospheric. Three years ago we replaced the valve and haven’t had a problem with air in the filter since.

Before we new the cause of our air ingress problem I would open the top of the Racor and fill the bowl with fresh diesel. It would take about 8 hours of engine run time before the amount of air in the bowl increased to the point of worry.

Hope this helps.

…..Ed

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Ed and Marlene Brost

SaSeaCat N30U #322

Sarnia Yacht Club

Sarnia Ontario

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I’ve the same setup but don’t have a problem with air. I guess if the valve was partially clogged it could cause it. This might have been discussed before.

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA


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The mechanic who figured out what was wrong with our system said that because the valve is rarely operated it was likely scratched when we closed the valve when changing a fuel filter.

The valve plug is a brass cone kept tight with a spring and the seal is based on a machined fit. Any imperfection in the mating surfaces would result in air ingress. He said this problem is common with older boats.

…..Ed

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Ed and Marlene Brost

SaSeaCat N30U #322

Sarnia Yacht Club

Sarnia Ontario

5

Interesting, Ed!

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA


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It turns out that the Racor fuel filter bowl had a hairline crack at the bottom, where the drain valve is. I’ve got the old bowl, will see if I can photograph it.

It was found by the mechanic - took the boat back to the marina to have another problem looked at, and when I tried to start the boat to move to another slip, engine would not start.

As the mechanic had put a new beta 20 engine in 7 “engine hours” ago and ran her for an hour under test conditions, AND is very proud of his work, he dove in, and found the issue, (a very small stream of bubbles), carefully tightened the bottom fitting, and the small stream grew into a large stream - and replaced the bowl without questions asked.

One happy camper here!

John NS26C 046 Kingston ON.