Type 1 Mechanical Fuel Pump Inlet/Outlet

Carbs & F.I.

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dtrumbo
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Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by dtrumbo » Mon Apr 30, 2012 11:35 am

Hi all,

As I should, I have a Type 1 (upright) engine in my wife's '70 bus. It has the mechanical fuel pump that lives right next door to the distributor. This bus has an alternator so the pump is the kind that has it's head cocked to the side like your dog when he's confused. Speaking of confused, I didn't pay attention when I disconnected the hoses and now I'm wondering which is the input and which is the output of the fuel pump. I believe the input to the pump from the tank was connected to the upper nipple and the output from the pump to the carburetor(s in my case) was connected to the lower nipple. Can someone confirm how they're supposed to be hooked up if it even matters? I'll spare you the gory details of why I had to disconnect the fuel pump until I'm certain of what I think I know and can articulate it in a helpful way very much unlike this sentence.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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sped372
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by sped372 » Mon Apr 30, 2012 12:12 pm

It does matter, but it can be different from pump to pump. There's no hard and fast rule to which is 'in' and which is 'out' based on my experience.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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ruckman101
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by ruckman101 » Mon Apr 30, 2012 12:36 pm

I believe mine go into the bottom and pumps out of the top to the carb.


neal
The slipper has no teeth.

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hambone
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by hambone » Mon Apr 30, 2012 2:09 pm

My vote is top too. Wurst-case hook up the pump and see what it does.
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SlowLane
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by SlowLane » Mon Apr 30, 2012 5:43 pm

With the +12V wire disconnected from your coil and carefully avoiding any contact with the fan-belt and pulleys by hair/skin/neckties/pets, gently put two of your fingers over the two pump ports. Ask your wife to crank the engine a few turns. You should feel slight suction on one port and the other port should "puff" your other finger away. Suction port goes to tank, puffing port goes to carb.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
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dtrumbo
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by dtrumbo » Tue May 01, 2012 7:42 am

SlowLane wrote:Ask your wife to crank the engine a few turns.
Wife? We don't need no steenking wife! I gots me one o' these!
Image

Attempted comedy aside, that's an excellent plan. I looked at older pictures and I'm pretty sure the inlet to the pump is/was the top nipple. But the new pump isn't the old pump so double-checking using the SlowLane method makes even more sense. I need to use the no-start-but-run-the-pump method anyway to check fuel pressure. Dual Webers no likey excessive fuel pressure.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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SlowLane
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by SlowLane » Tue May 01, 2012 10:18 am

Well, the consequences of getting it wrong are pretty benign. You'll just crank and crank and wonder what that bubbling sound is coming from your fuel tank. :drunken:
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

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ruckman101
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by ruckman101 » Wed May 02, 2012 7:30 pm

I can attest. While the fuel pump on Bertha Bus feeds the bottom spigot, and pumps to carb out the top, it's the other way around for the fuel pump on Gretchen Ghia.

New engine wasn't getting gas until I swapped the lines. Listening for bubbles was less than definitive, fingers over the spigots and cranking not real clear either. A chunk of fuel line on the top spigot and a cup of gas to drop the line in and no bubbles but a spurt out the bottom spigot made it clear.

Now we be good.


neal
The slipper has no teeth.

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dtrumbo
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Re: Type 1 Mechanical Fuel Pump Inlet/Outlet

Post by dtrumbo » Thu May 03, 2012 4:31 am

Yep, last night I hooked up my starter switch and turned the motor over a couple of times to see fuel out the bottom nipple. Now to set fuel pressure. Two gaskets are giving me 4 PSI. My Weber guru sez it needs to be between 3 and 3.5. Now I need to make another gasket.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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