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Merc 7.4L fuel filter

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seidh

New member
Hi,
i changed oil and oil filter, and water separating filter on my boat, and now it woun't start. In order to change oil i had it running for 1/2 hr at the dock. I removed old fuel filter and installed new one.Engine cranks but doesn't start, apparently fuel delivery problem. I'm thinking if i pushed some debris in the line when i was replacing fuel filter, would that cause clogged line and fuel starvation?
I can't think of anything else. How do I check the lines and clean them? Thanks a lot. Seid.
 
Sometimes it takes a minute to re prime the fuel system after changing the fuel filter, you might have to try to start it 5 or 6 times before it catches.
 
You have to fill the new fuel filter with fuel before you install it. You can crank it until the battery is dead, it will not start unless you fill the filter.
 
I was thinking about filling it with fuel, even looked in the service manual but didn't find anything about it. Just out of the curiousity, if you fill it with fuel how does it work (separates water from fuel)?
 
seidh said:
I was thinking about filling it with fuel, even looked in the service manual but didn't find anything about it. Just out of the curiousity, if you fill it with fuel how does it work (separates water from fuel)?
Click to expand...

Ayuh,... Water is separated by Gravity....

As fuel passes through the filter, the water falls to the bottom....

If, 'n when the canister is Full of water, it'll pass the water....
 
Thank you all for your answers and replies,
I guess I need to fill the filter with fuel first and then start the engine. I read in one of the older treads that good way to clean fuel lines and injectors is to fill the filter with Sea Foam and then run the engine. Have you guys had any experience with that?
Txh
 
I run the engine just a few minutes, turn it off and then let the boat sit several hours or overnight. It works great on carbs when they sit overnight...SF dissolves any old fuel varnish improving idle.
 
silly question but do you have the fuel going in the right direction into the filter? I did that one time on accident, took me a little while before I realized what I did wrong.
 
seidh said:
1.... I was thinking about filling it with fuel, even looked in the service manual but didn't find anything about it.
2.... Just out of the curiousity, if you fill it with fuel how does it work (separates water from fuel)?
Click to expand...
1.... The risk in handling fuel in an open fuel filter cartridge is likely the reason the OEM does not mention pre-filling the cartridge.
However, it is the method to ensure a re-start.
Also helps to fire the engine up and shut it down, prior to a filter change.


2.... IMO, the standard Merc and Sierra style filter cartridges rely on gravity (as mentioned) and the media's asorbtion ability.
This limits their ability to absorb much water. If you want a more true water separating fuel filter, look at the RACOR replacement kits.

The RACOR cartridge and all metal bowl are required for I/B's and I/O's, and can be retro-fit to your existing base adapter if you know the thread size.
No plumbing changes are needed.


images


Sierra and GLM also sell this product these days.

images





FYI: the metal bowl must be used for enclosed gasoline engine I/B's and I/O's.
9-37885_0.jpg
 
Docksidemarineservices said:
The filter media does not let water pass through.
Click to expand...

The filter media stops water from passing through while the fuel is flowing. Once the engine is shut down and the flow stops gravity takes over and the water settles to the bottom. If the media is submerged completely in water, of course the vacuum created by the fuel pump will cause water to pass the media and enter the engines fuel delivery system.
 
+1 on the filter selection Rick. Is this an electric fuel pump app or mechanical? In both cases, I fill the filter first. If the fuel pump is electric and you run it dry, you will drastically reduce its life. It doesn't take very long for that to happen when dry. It gets lubricated by the fuel. These whistle a bit while running but if it screaches while it's running, chances are it's on its last legs and should be replaced now before it fails out in the middle of nowhere.
 
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