Racors sucking air?

Hi all,
Has anyone had issues with Racors sucking air and causing the motor to die as a result?
After 29 faithful years, the Racor on my genny pooped out. I did a complete rebuild with a seal kit but it still kept sucking air causing the engine to die. Finally bought a new racor assembly and that fixed it.

Anyone else experience this?

Taras

Did you check closely if the o rings were straight? Easy to get a 90 degree twist that can barely be noticed

Taras, It might help to know which type of Racor filter you have. I'm guessing it was either a #120 or a #500

Close the valve on the diesel tank.
Solve the diesel line in front of the engine and conclude provisionally a diesel electric pump (I have such a thing as a spear for my gens) on this line with diesel. With this pressure can you see where your filter has a leak.Alwais give a succion system pressure und you find the air leak.
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Norbert

Since my Keel Tank was empty, this was introducing air into the system. I shut that valve off and the air leak stopped. This seems weird to me. I have two saddle tanks that I typically use. Plenty of fuel in those. The keel tank however is empty.
Has anyone else experienced this.
Taras

I have 6 dieseltanks on board (1200 gal.en total) 3 tanks are filling per gradient the keel tank with manual valve. I fill and trim with a transfer-pump from the keel tank the two maintanks . The two main tanks are higher than the engine and so always without air problems in the system.
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Norbert

The two main tanks are higher than the engine and so always without air problems in the system.

Gravity is every cruising boats friend , Untaxed (so far) and a fuel leak is 100,000 times easier to find than an air leak.

For folks with cruising ideas an electric pump from the tank,(with valves that could pressurize the lines filters and even prime the engine might be a great low cost addition.

FF said:

The two main tanks are higher than the engine and so always without air problems in the system.


For folks with cruising ideas an electric pump from the tank,(with valves that could pressurize the lines filters and even prime the engine might be a great low cost addition.

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Understatement in my experience. Electric pump primes an engine, and in most cases can overcome an air leak by pressurizing the fuel line turning the air leak into a fuel leak. Was able to get back to port with an air leak using an electric fuel pump. Was in open water between islands and not in a good place to investigate what the problem was.

Bay Pelican said:

Understatement in my experience. Electric pump primes an engine, and in most cases can overcome an air leak by pressurizing the fuel line turning the air leak into a fuel leak. Was able to get back to port with an air leak using an electric fuel pump. Was in open water between islands and not in a good place to investigate what the problem was.

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Marty,
i have an electric fuel pump with a fuse and a switch and a fuel filter mounted on a board for emergency and can bridge quickly other pumps .
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Norbert

I have had troubles with the Racors with the small priming pump. They started losing a prime. Finally replaced O-ring on pump, and stopped using them to prime system. DS

In recent months my engine would stall immediately after starting. I had to prime the engine before restarting even after having turned off the engine for an hour or more. Replacing the rubber gaskets on the twin Racor 500s solved the problem. The gaskets had become hard and weren't making a good seal.

markpierce said:

In recent months my engine would stall immediately after starting. I had to prime the engine before restarting even after having turned off the engine for an hour or more. Replacing the rubber gaskets on the twin Racor 500s solved the problem. The gaskets had become hard and weren't making a good seal.

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By gaskets are you referring to the large O-Ring that comes with every Racor filter element?

Bay Pelican said:

By gaskets are you referring to the large O-Ring that comes with every Racor filter element?

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Yes, as well as the little one for the turnbolt securing the lid holding the large O-ring.

Racor Problem

Had similar problem with my Racor 1000 series. In addition to changing gaskets I changed the floating "check ball" in the assembly. I believe the ball floats up, against a seal when the engine is shut down which would then prevent loss of prime.
The Racor parts numbers:
Replacement Check Ball Kit: RK11028B
Service Kit: RK111404 includes check ball, cap screws and gaskets

Bay Pelican said:

Understatement in my experience. Electric pump primes an engine, and in most cases can overcome an air leak by pressurizing the fuel line turning the air leak into a fuel leak. Was able to get back to port with an air leak using an electric fuel pump. Was in open water between islands and not in a good place to investigate what the problem was.

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Me too. But my problem was caused by me.

I had transferred all the fuel from one tank to the other and did not close the supply valve.
Genny did not like that.
Used electric pump to get genny to run again.
Then, two days later, when i did the exact same thing, I had to use electric pump to prime racors to get genny to run again.

The little pump that can (pump and prime):

Racor recommends that any electric booster pump be on the suction side of the filter, between the filter and the motor. If you pressurize a Racor they say you will sooner or later blow the seals.