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Mechanical fuel pump


Flo1993

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Not getting any fuel to carburetor so i installed a new mechanical fuel pump and still no fuel to the carb

 

The new pump has an arm that is a little bit bigger than the old pump. I was told i have a z20 but the local parts store is telling me that the bigger arm is for a z22 so i am lost. How do i know if the arm is making contact

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The '80 720 was L20B powered. The dipstick should be on the passenger side. Look just behind the handle and stamped on the flat spot on the block will be L20B

 

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Now go get an L20B pump.

 

 

Why are you replacing the pump? If no fuel have you checked that the tank is not empty? That the fuel filter is not clogged? That the fuel lines is not clogged?

 

Get a small pop bottle with gas and put the hose to the pump into the bottle. Put the output hose into another container. Pull spark plug wire off coil so engine does not start and turn engine over with starter. You should see fuel gush in spurts into the receiver container.

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Not getting any fuel to carburetor so i installed a new mechanical fuel pump and still no fuel to the carb

 

The new pump has an arm that is a little bit bigger than the old pump. I was told i have a z20 but the local parts store is telling me that the bigger arm is for a z22 so i am lost. How do i know if the arm is making contact

 

 

You'll know if you pull the valve cover and look.

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If carburetor is on the paassenger side and exhaust on the driver's side then you have a Z series engine. Only the Z20 and the Z22 could have had a mechanical fuel pump. To ID this engine look between the two pair of exhaust pipes on top of block. It's stamped there just below the #2 and #3 spark plugs....

 

Q9xYbRS.jpg

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I figured it out. The new pump has a longer arm so i had to remove the spacer. I took off the cover and saw that it was making contact. The old pump leaked gas out by the arm.

Yeah, that sounds backwards. If it has a longer arm and you took the spacer out, it would be making the problem worse.

 

You can check pump operation by removing the valve cover and pumping the arm by hand, or with the pump unbolted from the head, again, with your hand.

 

Sounds like you need to verify which engine you have too.

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I cant see the engine ID because theres some grease on the flat spot so ill clean that off in a bit so i can just know what I have for sure. All I know is the guy I got it from said it was swapped and an auto parts guy told me its a z20

...its better to make sure...the guy you got it from may or may not know until you check. What's that Russian saying "believe but verify".
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