Pump Me Up
A mechanical fuel pump replacement made easy.Replacing your fuel pump is not as common a weekend upgrade as it is a maintenance dilemma. Spots of fuel on the garage floor often mean that your fuel pump diaphragm is on the fritz. For some, fuel-pump replacement is a desire to increase the fuel flow to their engine. Either way, the change can be relatively simple if you have the right tools and a little patience.
The factory mechanical pump is located on the passenger side of the engine, mounted low up front. Remove anything that is in the way. The radiator and shroud need not come out in most cases. After unhooking the battery, to avoid any random accidental sparks, carefully break free the fuel lines. There are two located on most pumps, one in and one out. Remove them with the proper flare wrench, and pull them free of the pump being careful not to bend or kink the lines.
Next, remove the pump from the engine by removing the two bolts that hold it to the block. Once the pump is loose, remove it, making sure to catch the large, cylindrical pushrod behind the pump lever that activates the pump. Often it will fall out once the pump is out. A tip for installing the new pump: Clean off the pushrod, and coat it with white grease to keep it from slipping out of the engine. Remember to use a new clean gasket at the point where the pump meets the block. This will avoid any future oil drips.
Parts List
Time *1 to 4 hours
Tools
* Assorted sockets and ratchet* Flare wrenches for use with flared fittings* White grease to keep pushrod in place
Tuning You In
A quick Holley-carburetor tune is what the Doctor ordered.Tuning a Holley carburetor is a relatively simple operation. the better you get at it, the less messy it will become. The messiest part is setting the fuel-float levels. If your car stalls or leans out on hard starting or stopping, often the float levels are to blame. The key here is to try and let the least amount of gasoline escape from the carburetor-adjustment screw area. Excessive fuel can ignite and cause flamb of Corvette, and that would ruin your whole day.
Remove the fuel-bowl sight screw/plug from the primary fuel bowl. Bounce the fender of the car. If fuel slightly dribbles from the hole, you can skip this step. If you see either lots of fuel or nothing, it's time to set the float level. Using a box end wrench, loosen the lock nut that holds the adjustment screw, and then snug it back up to keep it from leaking. Start the engine. Place a rag under the carburetor to soak up the fuel. Turn the adjustment screw slowly after backing off the lock nut. Once fuel starts slowly draining from the sight hole, turn the lock nut and then replace the sight plug/screw. Be very careful with the fuel-soaked rags; they can ignite if they touch hot items like headers.
Next, hook up the dwell/tachometer to your ignition underhood. Start the engine. Using a small tuning screwdriver, turn the fuel/air screw located on the carburetor body (on engines where such adjustment is allowed). Work to find the peak idle rpm. Once you have located the highest rpm, you're finished. Adjust the idle speed to the recommended specs for your engine.
Parts List
Time* Less than 30 minutes
Tools
* Large flat-blade screwdriver* Open-end wrench* Tach/Dwell meter* Small flat-blade screwdriver* Rags to soak up fuel