Technical Can i leave mechanical fuel pump on engine when installing electric one ?

if the stock mechanical isn't getting the job done- i'd either fix/replace the stocker or go electric- not both. If appearance it important, then gut the stocker (or pull the pump rod) and just run the electric through it. I wouldn't bother using an electric to crutch a known-bad mechanical-rick.

 

Saxon, you wrote "Also depending on what 2x2 barrel intake you might need a different length fuel push rod." Bingo, i bet you got it. I looked at the Offy intake on Dads 53 and the pump mount sits 1/4" higher on it than the stock intake.

Electric pump is on hold, gonna get a longer push rod and install it first.

Thanks !

 

I would like to add that a mechanical fuel pump without fuel pressure is just a spring loaded lever banging off the lobe(might hear it rattle) without fuel on the other side of the diaphragm.... if you swap to electric and leave it in place without function I wouldn't expect the diaphragm to last long and when it ruptures it creates a opening in the crankcase.... Causing a mess of odd running and driveability issues... the electric pump teamed up with the mechanical pump could be another route for sure but, why? Like others have said... Fuel in the crankcase is no good and the electric pump could definitely cover up the mechanical pump if it goes out. Mike

 

My dad has a toggled electric pump on his 56 to prime the carbs and it certainly helps get it started faster. I don’t have one on my 56 but I kinda like turning the engine over and getting the oil moving around before it fires up. I would say there are times it takes longer than I like (especially when it’s cold) and wish I had one to prime it not worry about the battery. I think I’ll do that in the future.

 

I would think by now he has figured it out after 6 years

 

We ended up removing the mechanical fuel pump. We never ran both at the same time. Were told by some it wouldn't be an issue to leave the mechanical while others said it would/could be.

 

I ran both on my 51 Merc .It vapor locked all the time down in the south Fl. heat back in the 60's.
It had a Carter pump. Worked fine with both.
Used 2 Holley blue pumps on a G/Gas car. Ran them through a Carter Racing mechanical pump .Used the mechanical as a regulator. Ran under the NHRA index with the car. Know better now and would just use a single big pump and a regulator. Didn't know any better back then. Got lucky I guess.