Fuel delivery issue

Fleet

.
Feb 8, 2021
27
Catalina 310 108 Lake Guntersville
Drained old fuel from the tank. Put 10 gallons of fresh fuel in. Pulled the pickup line and cleaned it. Verified both shutoff valves on the tank supply and return are in the "flow" position. Replaced the Racor filter and fuel filter on the engine. Filled the Racor filter. Turned key to first position, hear something that sounds like a fuel pump. Run it for awhile and try to start the engine. Will turn over but won't start. Turned key to the second position, warm glow plugs, for around 30 seconds. Engine won't start. Appears no fuel is getting through. Disconnected input fuel line to Racor. No fuel coming through. Connected the fuel line back and operated the manual pump on the Racor. Still won't start. So a couple of questions. What turns on (what am I hearing) when the key is turned to position 1? Is there anything between the tank pickup line and the Racor fuel input? I'm going to go back tomorrow and blow into the Racor fuel input line and see if I can blow air into the fuel tank. Any other suggestions?
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
What turns on (what am I hearing) when the key is turned to position 1? Is there anything between the tank pickup line and the Racor fuel input?
Just making a few assumptions/guesses:
The sound you hear is likely an electric fuel pump. It could be before or after the Racor (it should generally be after but many are before). You should follow the sound to see where that pump is.

You can often tell if the pump is working by listening to it just after turning on the key. In my experience the pump makes a relatively fast clicking noise at first and then slows down as the pressure builds up. If it doesn't slow down it means its not building up pressure. You might check if the pump has a built in filter and if it does clean or replace that or otherwise service or replace the pump.

 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Sounds like you have air in the fuel line from the tank to the Racor. The line probably lost it's prime when you pulled it from the tank to clean it. You could re-establish a siphon by forcing fuel back up the fuel line to the tank. It would help to fill the tank. Often on the C310, a full fuel tank provides enough pressure to feed the engine without the lift pump operating, but you need that siphon to be established.
Once you have established fuel flow to the Racor, the rest of the system should bleed any remaining air by holding the key switch all the way on for 30 seconds or so. You should hear the lift pump clicking while you hold the key switch on. You might need to fold the companionway stairs forward to be able to hear the pump.
 
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Likes: SV At Last

Fleet

.
Feb 8, 2021
27
Catalina 310 108 Lake Guntersville
Engine is Universal M25XPB.
Stu: I saw that check ball valve when messing with my Racor. I'll verify that is free floating
Tom: In our 310's, am I correct in assuming that there isn't anything between the Racor input and the fuel tank supply? I think I can actually use the hand pump on the Racor to prime the fuel line to the Racor. What is being turned on when moving the key to the start 1 position? Whatever it is, is located in the aft section but I can't see it or pinpoint it.
 
Nov 16, 2017
59
Catalina 310 #246 TX
Pretty sure Tom has provided you with the answer. The fuel tank is above the fuel/water separator so it is gravity fed. It should free flow when you remove the supply line to the filter. Since the lines exit the top of fuel tank they need a siphon established to get over the “hump”. I am always envious when I read that some are able to bleed their fuel systems by turning the key. Even the Universal manual says it’s true, but it never works for me. I have to bleed at the secondary fuel filter and the injectors To get the air out. On #246 the lift pump is between the Racor and the engine mounted fuel filter in the starboard aft of the engine.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Engine is Universal M25XPB.
Stu: I saw that check ball valve when messing with my Racor. I'll verify that is free floating
Tom: In our 310's, am I correct in assuming that there isn't anything between the Racor input and the fuel tank supply? I think I can actually use the hand pump on the Racor to prime the fuel line to the Racor. What is being turned on when moving the key to the start 1 position? Whatever it is, is located in the aft section but I can't see it or pinpoint it.
I'm not sure what you mean by the start 1 position of the key switch. By holding the key switch on all the way, you activate the glow plug solenoid and the lift pump. Usually, holding the key on for 30 seconds or so will bleed the system, assuming the Racor was filled when installed. I have never had to use the manual bleed on the Racor, so I don't know how well that would work. As AT Last mentioned, you have to get the fuel up and over the top of the tank to establish a siphon.
 

Fleet

.
Feb 8, 2021
27
Catalina 310 108 Lake Guntersville
Turning the start key to position 1, the key stays there and something that sounds like an electric pump turns on. Guages become active. Position 2 is momentary and activates the glow plugs and lift pump. I totally understand that I've got to get the fuel over the hump and into the Racor. I'm going to pull the output line from the Racor and use the Racor pump to try to get flow. Once I establish that, I'll work my way down the fuel system. If there isn't a fuel pump between the tank supply and the Racor, I'd still would like to know what pump or device turns on when I turn the start switch to position 1.
 
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Likes: Tom J
Jun 11, 2004
1,621
Oday 31 Redondo Beach
If there isn't a fuel pump between the tank supply and the Racor, I'd still would like to know what pump or device turns on when I turn the start switch to position 1.
Have you ruled out that it might be a fuel pump between the Racor and the on engine filter?
That's where it should be.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
If there isn't a fuel pump between the tank supply and the Racor, I'd still would like to know what pump or device turns on when I turn the start switch to position 1.
You might want to have someone stand over the engine while you turn on the switch. Your low oil pressure alarm should sound when you turn on the key to position 1, and then stop when you go to position 2. If you don't hear the alarm, then you might be hearing the lift pump coming on, which would indicate the oil pressure switch is shorted.
 

Fleet

.
Feb 8, 2021
27
Catalina 310 108 Lake Guntersville
It probably is the exhaust fan that is turning on. Verified I have fuel coming out of the Racor. Do not have fuel coming out of the lift pump. Shorted the power lead of the lift pump to 12V and got nothing. No noise, no activity. Ordered a new lift pump and oil pressure switch. Let's see if that solves my problem. Thanks for all the advice
 

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
On my -310, the fuel will gravity feed as long as the tank is half full or more. The Racor, located under the rear bunk, is the lowest part of the fuel line. From the Racor to the electric fuel pump located on the starboard rear of the M-25 XPB, there is a rise in the line, but still below the 1/2 level in the fuel tank.
There is a bleed valve on the M-25 XPB, but the system is self bleeding. Still, you can open the bleed valve a crack and have someone turn the key to the second position, which ignites the glo-plugs and turns on the electric fuel pump (rapid clicking noise). Fuel should come out. If you are not getting any, then you are not getting fuel to the fuel pump. I would then check to see if there is a blockage at the Racor.

Do you have a Fuel Return Line Shut Off Valve? It needs to be full open.
 

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JRT

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Feb 14, 2017
2,037
Catalina 310 211 Lake Guntersville, AL
Hey Fleet, give me a call. Been traveling and busy at work. I'm almost certain you need to fill the tank like Tom and KZW said.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
It probably is the exhaust fan that is turning on. Verified I have fuel coming out of the Racor. Do not have fuel coming out of the lift pump. Shorted the power lead of the lift pump to 12V and got nothing. No noise, no activity. Ordered a new lift pump and oil pressure switch. Let's see if that solves my problem. Thanks for all the advice
Maybe verify that the lift pump has a good ground. I recently found several corroded connections on the glow plug solenoid, next to the lift pump. When you go to position 1 on the key switch, do the warning lights come on and does the alarm start beeping?
 

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Tom J

Can you post a picture of this connection?
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Tom J

Can you post a picture of this connection?
Sorry, but my boat is on the hard, and I am back home in Hawaii, so no pictures. The connections for the lift pump and the glow plug solenoid are grouped together on the aft end of the engine, above the transmission. On my engine, they were still painted over from the factory installation, but some were loose and had corrosion on them.
I am still wondering if your alarm sounds when you go to position 1 on the key switch.
 

Fleet

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Feb 8, 2021
27
Catalina 310 108 Lake Guntersville
Sorry about the late responses, was out of the country and just got back. I don't think I have a return fuel shut off valve. Will look to verify. I know there is a shut off return valve on the gas tank. No alarm sounds when going to position 1 on the key switch. New fuel lift pump and oil pressure sending unit were delivered while I was gone. Will look at installing them this weekend. Hopefully the new oil pressure sender will solve the lack of alarm sound.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Sorry about the late responses, was out of the country and just got back. I don't think I have a return fuel shut off valve. Will look to verify. I know there is a shut off return valve on the gas tank. No alarm sounds when going to position 1 on the key switch. New fuel lift pump and oil pressure sending unit were delivered while I was gone. Will look at installing them this weekend. Hopefully the new oil pressure sender will solve the lack of alarm sound.
If you don't have the wiring diagram for the 12v circuits, you can go to the s/vSmitty site and download the owner's manual. The circuit for the alarm is unusual in that positive 12v is fed to the lift pump to energize it, and the same 12v silences the alarm.