Mercury Cougar Owners banner

1 - 13 of 13 Posts

·
Premium Member
Joined
·
2,303 Posts
Discussion Starter #1
Now that the Petronix is all straightened out I ran into an issue of no fuel. As you may remember, last year I replaced all fuel lines and the fuel pump. The Carb was rebuilt about 6 months beforehand. The only thing I haven't replaced is the gas tank and the fuel sending unit. Today I pulled off the rubber connector between the rear fuel line and the one going into the fuel pump. I then set up a gas can about the same height as the engine and it turned over and fed from the can so I know the pump is good.

Now it might just be as simple as being out of gas but I didn't want to pour 5 gallons into the tank just to find out I had to take it out anyway. So the question is can the sending unit go bad in such a way to cut off fuel flow? If so, then for my own peace of mind, I'll pull the tank and replace the sending unit.
 

·
Premium Member
Joined
·
413 Posts
Yes, your sending unit can be clogged. You can try blowing compressed air through it.
 

·
Premium Member
Joined
·
13,577 Posts
There is a sock on the end of the sender fuel tube, this is what can clog.
 

·
Premium Member
Joined
·
413 Posts
The tube can also clog, just like the rest of the fuel line. The filter sock has probably fallen apart after 43 years.
 

·
Premium Member
Joined
·
2,303 Posts
Discussion Starter #5
As I remember it wasn't in the best of shape the last time I looked at it.

Who has a good replacement?
 

·
Registered
Joined
·
1,853 Posts
My filter sock was gone! Sending unit was coroaded up pretty good. Figure that sock went someplace? Yup you can really restrict flow with a clogged up sender. Easy enough to pull out and clean though. don't even need to pull the tank however I would at least flush the tank out too.
 

·
Premium Member
Joined
·
2,303 Posts
Discussion Starter #8
I saw that but I was going to replace the entire unit and I also saw that Don doesn't think very highly of the ones he has for sale.
 

·
Premium Member
Joined
·
413 Posts
Yeah, I read that too. Scott Drake, the manufacturer of these sending units, claims they test 100% of their units. http://www.drakeautomotivegroup.com/Store/Product/C8ZZ-9275-C.aspx?wid=141

I'm going to pick up one of these when I switch to 3/8" stainless fuel line.
http://www.virginiaclassicmustang.c...S-FLOAT-BEST-QUALITY-38-INCH-INLET-P2376.aspx

For now, I just cleaned out my sending unit with carb cleaner and compressed air and put it back in. Then I put some MMO in the tank to keep it clean.
 

·
Premium Member
Joined
·
2,303 Posts
Discussion Starter #10
How much MMO per tank?
 

·
Registered
Joined
·
1,044 Posts
if you put a piece of rubber line on the sender out let and blow into it with the cap off---if you hear bubbles the sender is clear---if there is a minute crack in the hose comming out of the tank , it wont suck---if every thing is new and clean , i'd recomend a fuel filter near the sender
doctordesoto
 

·
Premium Member
Joined
·
413 Posts
MMO is $17 per gallon and it takes about 6 oz per tank. $0.80 per tank. I use it mostly because of my compression ratio (12:1). I can't tell the difference between 91+MMO and av gas.
 

·
Premium Member
Joined
·
2,303 Posts
Discussion Starter #13
I had time today to pull the tank and what do you know, the sock had disintegrated. Glad I replaced the sending unit because the float was full of fuel. I ran the air hose through the line just to make sure there wasn't any further blockage and put 3 gallons into the tank. Poured a splash into the carb and she fired right up and sucked in the fuel from the tank. I am not sure if the gauge is working or not considering it isn't but an eighth of a tank. Carb is a mess with the idle circuit (Motorcraft 4300) but I am making progress.
 
1 - 13 of 13 Posts
Top