Lift pump oddity MF275

jjgurley · Mar 22, 2020

I bought a replacement lift pump (from YT) and it didn't go as expected. The "lever" that rides on the lobed cam on the crankshaft was too long (or too straight) such that the lever never relaxed, hence the pump never pumped. I ended up swapping just the lever and associated pivot parts with the old one in order to get it to work properly, or at least pump at all.

Anyone had a problem like this?

I'm thinking of changing to an electric fuel pump, so if anyone can suggest a pump and maybe reveal the secret of the thread sizes, it would be great!

Dieseltech · Mar 22, 2020

The lever rides on the camshaft, not crankshaft. There are several supply pumps for Perkins engines, latest on some engines use a four bolt mount. Easy to get the wrong one with so many choices.

jjgurley · Mar 22, 2020

I had based my coice on SN. Four bolt, but even after swapping the lever, the odds of getting the engine in a position where there's any manual pumping action is about 15%. The lobe must be mostly lobe and not much valley.

Still feel better with an electric...

ptfarmer · Mar 22, 2020

Fuel pump part number should be 1447017M91 (Perkins part number 2641711).

jjgurley · Mar 23, 2020

That's the number I ordered.

The new pump had a stamped finger while the old one was two pieces of thicker steel riveted together. The new one was "straighter" than the old, and after installation, the new one never relaxed enough to allow the hand lever to operate. It couldn't be installed unless I turned the engine to get the lobe minimized.

After swapping the fingers, the new part installed as expected, and I do get some pumping, although I think it might be anemic - I don't have a way to test it.

The reason I think it might be iffy is that starting is very stubborn and unreliable. See my earlier thread about low compression.

Lift pump oddity MF275

jjgurley

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Dieseltech

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jjgurley

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ptfarmer

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jjgurley

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