I'm finally getting around to replacing my stock SS lift muffler with the Fiberglas muffler by Centek. After reading another thread regarding the removal of the old muffler, it looks like I'll have to disconnect the fuel lines going to the fuel tank just above the muffler. I've never disconnected a fuel line 'before' the fuel filter and wasn't sure if the fuel system has to be bled once the fuel lines are reattached. I would think the answer is no, but I'd hate to find out the hard way by having the engine die on me when I most need it.
Does diesel have to be bled if tank line is disconneted?
- Thread starter Joe Perez
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Most diesel fuel systems have to be bled if a butterfly flaps its wings in China. It's something you want to be able to do in your sleep though in case you ever have to change a filter in a situation where you may need the engine to save your boat.
Do you have an electric fuel lift pump? If not, it's worth installing just for ease of bleeding. If you have a gravity feed tank, fuel will flow through the pump when it's off so you don't need to run it all the time. No harm in running it all the time if it's the pressure cut off type as fuel will just flow through it. Many gravity feed fuel systems need a pump to get the siphon action out of the tank started.
Wire a push button switch, you can use a regular doorbell if it's a dry location, (I assume we are talking diesel here) from the 12 volt buss with a fuse to the fuel pump. Located it so you can easily reach it with a wrench on the engine components. Have lots of the absorbent fuel clean up pads on hand.
If you don't have a manual for your engine, now is the time to track one down. Read the bleeding instructions.
Basically, you loosen connections from the tank moving forward, pushing the push button until bubbles stop coming out, tighten, and move on to the next connection. Finish at the injectors.
People will tell you that you can bleed by pushing the little lever on the engine mounted fuel pump. They are right but life is too short and already tough enough.
Give the engine a good run before you leave the dock as you may have missed a few bubbles and still have some stumbles and restarts.
Do you have an electric fuel lift pump? If not, it's worth installing just for ease of bleeding. If you have a gravity feed tank, fuel will flow through the pump when it's off so you don't need to run it all the time. No harm in running it all the time if it's the pressure cut off type as fuel will just flow through it. Many gravity feed fuel systems need a pump to get the siphon action out of the tank started.
Wire a push button switch, you can use a regular doorbell if it's a dry location, (I assume we are talking diesel here) from the 12 volt buss with a fuse to the fuel pump. Located it so you can easily reach it with a wrench on the engine components. Have lots of the absorbent fuel clean up pads on hand.
If you don't have a manual for your engine, now is the time to track one down. Read the bleeding instructions.
Basically, you loosen connections from the tank moving forward, pushing the push button until bubbles stop coming out, tighten, and move on to the next connection. Finish at the injectors.
People will tell you that you can bleed by pushing the little lever on the engine mounted fuel pump. They are right but life is too short and already tough enough.
Give the engine a good run before you leave the dock as you may have missed a few bubbles and still have some stumbles and restarts.
If this were my boat, I'd bleed the fuel line just to be safe, and then run the engine for 15 min or so before heading for the first time afterward. If there is a problem, best to find it while at the dock.
FYI, I can change both primary and secondary fuel filters on my '86 Yanmar 2GM20F without having to bleed the system. I simply fill the cartridge holders full of fuel before reinstalling them. Engine always runs fine afterward. But I do bleed the system just to stay in practice should I ever really need to do this while on the water.
FYI, I can change both primary and secondary fuel filters on my '86 Yanmar 2GM20F without having to bleed the system. I simply fill the cartridge holders full of fuel before reinstalling them. Engine always runs fine afterward. But I do bleed the system just to stay in practice should I ever really need to do this while on the water.
Joe,
I assume that you have a P36-2. If so, there are two fuel lines in the way when you remove the old muffler. One is the line from the tank to the fuel filter or the pump (if you do not have a Racor filter ahead of the pump). The other is the return line from the engine to the fuel tank. If you only have to remove the return line then you will not need to bleed it. If you remove the main fuel line then you will have to bleed the line after you reconnect it.
I was able to remove only the return line from the tank and get the old muffler out. The return line on my P36-2 was the inboard line.
The simple answer is yes you will need to bleed the system at the engine filter if you disconnect the line.
Dave
s/v ARIEL
I assume that you have a P36-2. If so, there are two fuel lines in the way when you remove the old muffler. One is the line from the tank to the fuel filter or the pump (if you do not have a Racor filter ahead of the pump). The other is the return line from the engine to the fuel tank. If you only have to remove the return line then you will not need to bleed it. If you remove the main fuel line then you will have to bleed the line after you reconnect it.
I was able to remove only the return line from the tank and get the old muffler out. The return line on my P36-2 was the inboard line.
The simple answer is yes you will need to bleed the system at the engine filter if you disconnect the line.
Dave
s/v ARIEL
Thanks Dave. Yes, I should have stated I have a 36-2. The weird thing is that when I disconnected the fuel lines at the tank, no fuel came out the 'out' side. My boat gets used a lot, so I know it's not some other problem I have, since it runs great. I'll try bleeding anyway, but it seems like a lot of fuel to bleed in the 6' or so of hose between the tank and first filter. However, seeing no fuel drip out makes wonder if the fuel just spills back into the tank once the engine is shut off.
I noticed the Centek lift muffler's inlet does not stick out as far forward as the standard ss muffler. Did you replace the entire hose or just couple an short piece? I'm thinking of replacing the entire hose, but it's in good condition. Hate to be wasteful.
That stock muffler sure was a bear to take out.
Regards.
I noticed the Centek lift muffler's inlet does not stick out as far forward as the standard ss muffler. Did you replace the entire hose or just couple an short piece? I'm thinking of replacing the entire hose, but it's in good condition. Hate to be wasteful.
That stock muffler sure was a bear to take out.
Regards.
Joe,
I elected to replace the entire hose from the engine to the muffler. Another trick done by our friend NYSAIL was to add a 90 degree elbow in the hose where it makes the sharp bend and I believe that gave enough hose to connect to the muffler.
If you replace the hose, the Vetus brand is much more pliable and easier to bend.
Good luck,
Dave
s/v ARIEL
I elected to replace the entire hose from the engine to the muffler. Another trick done by our friend NYSAIL was to add a 90 degree elbow in the hose where it makes the sharp bend and I believe that gave enough hose to connect to the muffler.
If you replace the hose, the Vetus brand is much more pliable and easier to bend.
Good luck,
Dave
s/v ARIEL
Glad I just read your reply, since I'll be shopping for exhaust hose tomorrow. I'll look out for the brand you recommended. Hope to finish the project in installments. Hope to have it done by Sunday.
Hello Dave...
Joe the 90 degree elbow made by Centek. It makes for a nicer fit in the engine compartment and less of a fight bending the muffler hose. I replaced the entire hose, cut it and fit the elbow in. You are going to love the new waterlift.
Joe the 90 degree elbow made by Centek. It makes for a nicer fit in the engine compartment and less of a fight bending the muffler hose. I replaced the entire hose, cut it and fit the elbow in. You are going to love the new waterlift.
Oh and about your original question.... if the fuel lines have never been replaced, now is a great time! Mine appeared to be the original fuel lines... when I went to remove them from the tank fittings I ended up having to cut the hoses off... seems like they fused.
I have not added the electric fuel pump... keep meaning to but never get around to it.
Good Luck
I have not added the electric fuel pump... keep meaning to but never get around to it.
Good Luck
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