Fuel line question

[nick de young]

Hello, I recently change my fuel filter, which included shutting off the fuel line from a valve. The fuel filter change went fine and atomic 4 ran fine for a few minutes, then starved itself from fuel and died. After investigating, I noticed it is not getting any gas pass the fuel filter (no gas in fuel filter bowl/housing). My question is would gas be free flowing out of the gas line with the valve open and the filter off. I tried it also with the engine cranking, but obviuosly not getting any fuel. I don'know if this is a clogged fuel line or something else. Any help would be greatly appreciated. This is for a 1978 Pearson 30.

[Mo]

Welcome

Hi Nick,
Welcome aboard. Why did you change the filter...was there a problem?
>>What type fuel filter
>>mechanical or electric pump?

-If it's the canister / separator type did you put a new "O" ring seal...should have come with it.
-installed the correct way.
-Fuel valve turned back to open.
-If the filter is the "in-line" type there is an arrow on them for direction of flow.
-Is there gas in the tank.
-there is also the possibility of a malfunction in the shut off valve and it is still in the closed position.

Do you have an MMI manual for the engine...good to have.

[edwardc]

Pearsons of that era often had an electric fuel cutoff valve mounted right at the tank. My 1977 P323 does.

It's hooked to the ignition circuit. Any chance you disturbed that connection?

Also, an electronic fuel pump should be able to prime the filter by itself, but a mechanical pump may need to be manually primed with the priming lever or an inline squeeze bulb.

[sastanley]

Just in case you don't already know this, don't crank the engine too long in a non-start condition without closing the raw water thru-hull..otherwise you can backfill raw water into the #4 cylinder & on up the line.

[smosher]

I have a 74 P30 and it does not have an electric fuel shutoff. I have the manual petcock that is right before the Filter. The Filter that came with the boat was a Fram which I couln't find replacements so I ended up replacing it with a racor using the same copper line with the flared nut. I did try the sierra replacement filter, but I didn't like the way it sealed. Gas will gravity feed through the filter when I open the valve.

On the fram filter I believe there is also a copper washer on the bolt that is used to tighen the bowl to the housing.

I would blow into the line and listen if it bubbles in the tank.

Any faint smell of gas after its been sitting for awhile, as this would indicate a fuel / air leak?

As Shawn pointed out this happened to me as the exhaust pipe cracked and there wasn't enough pressure to push out the water, so the crankcase and carb filled up with water. Took me awhile and many oil changes and carb cleanings to recover.

I like the P30 not much wind to get it up to hull speed.

Steve

[Carl-T705]

If the engine ran for a few minutes that may have been the gas that remained in the line or carb., I pulled the fuel line out of a can to run the engine out of fuel and was surprised to find the engine ran for several minutes before dying. An outboard inline squeeze ball would help to see if the line is clear. The turning of the shutoff valve may have dislodged some trash that is now blocking the fuel line, or the valve itself may have broken internally, remaining closed. It would be helpful to post the type of filter you replaced, inline, pump mounted, etc. Blowing air through the line would help in checking for an obstruction. As a quick note, you can make a very nice small portable air tank out of a old fire extinguisher by changing the fitting at the top to accept a tee fitting to accept a Schreder valve and a hose. I put about 75lb psi in the tank.

[msmith10]

Ed,
My experience with the Facet pump, on several occasions, is that it will not prime the filter. I have the touted rubber bulb that I put into the fuel line temporarily (I don't trust leaving it there permanently)just in front of the Racor to prime the filter. Once the filter is full, everything is fine, but the pump (and I've tried 2 different ones) will not prime the Racor after a filter element change.

[edwardc]

Interesting. I have the Facet too, but with a Sierra filter. It's never failed to prime it after a filter change.

[msmith10]

Ed,
Is your water separator located above, below, or at tank level? I relocated mine earlier this year-- it used to be a little above tank level, or even, at best. I placed it lower this year, so it was in a more protected location (I was always bumping it with gear previously as I would pull stuff out of the lazarette). I'm wondering if it will prime more easily now that it's lower. I haven't tried it yet.

[edwardc]

Its located in the engine compartment, rather than in a locker, and is below the level of the top of the tank, but above the level of the bottom.

[msmith10]

That's just how mine is now after relocation. I'll have to see how it works after the next filter change.

[hanleyclifford]

Ideally the fuel filter should be slightly below tank level so as to benefit from the syphoning effect. This makes repriming after an element change much easier.

[ndutton]

I plumbed and wired a filter purging system on my boat that uses the Facet pump to do exactly what has been suggested it can't (or doesn't very well) and my system works great.

After a cartridge filter change I turn one valve and flip one switch. The Facet ticks merrily away for maybe 60 seconds, the sound pitch deepens and the new filter is automatically purged of air. Works great.

Both my filter and pump are at the same level as the fuel tank so I'm not drawing uphill.

[domenic]

The great mechanical fuel pump.

Do you have to prime your mechanical fuel pump?
For the past year I have had to use a primmer bulb to get fuel to the pump.
I have been told, “If there is air in the fuel line, the mechanical pump would NOT work.”
That statement is not so. If the hand primmer on the pump is easy to move, it means the two springs in the pump need to be replaced. I replaced the two springs. Cleared the fuel line of all fuel…hit the starter button, and within two seconds my A4 fired right up. My fuel tank is six feet away from the pump, and the engine fires up every time.
Before I shut down the engine I turn the fuel off at the tank, and empty the line and pump of all fuel. My A4 never fails to start…check the springs in your pump. If the hand primmer on the pump is easy to move, replace the two springs.
I also replaced the stupid hose shoe copper tube from the fuel pump to the carburetor. I replaced the two L shaped fittings with two straight fittings. Ran a flexible fuel line from the pump to the carb. Also on this fuel line I put a small filter as used on outboard engines.
My fuel tank is six feet away from the pump, and 2.5 feet above the engine. My fuel tank ( the new one) is now in the lazarette. The old tank is below deck. I do not like green cheese, or fuel below decks. My old fuel tank is a great storage locker.