Jacobsen Chief 1000 fuel problem

I have a 1966 (I believe) Jacobsen with the K241 Kohler engine. After a complete engine rebuild, sandblasting, and paint, I got it back together to find the original fuel pump no longer worked. I ordered a new pump from a place called manufacturer's supply company, since I ccouldn't come up with a diaphragm for the original. I had it running and everything seemed fine. This was probably a month ago at least. I finally got back to work on it now and when I had it running it is pushing gas out around the clamped on fuel line and out of the carburetor. I am almost positive it did not do this when I put it in. I should add the carb has been rebuilt with a Kohler carb kit. I am wondering if it is possible for that plastic fuel pump to over pressurize the system? Is there some sort of relief valve inside them? Should I maybe have spent the extra money for a Kohler pump? Also, in theory, because of the location of the fuel tank, would it be possible to eliminate the pump and let gas gravity feed? I would really like to gut the original metal one and let gravity push gas to the carb but I think that's asking a lot. Thanks for the help!

If your fuel tank is higher than the carb it should gravity feed
fine, that's how a few of mine are,I have a Briggs and Stratton
16hp and a kohler k181 that gravity feed and run fine.

The carbs use two different seats I believe. One for a fuel pump has a smaller hole.

Needle and Seat kit with fuel pump-KOH1252104

Needle and Seat kit without fuel pump-KOH1252103

Make sure the line isn't split.
Check the bowl real close to make sure it doesn't have a pin hole. Wipe it off, dry with air and open fuel valve to see exactly where fuel is coming from.
Check the fuel pressure to make sure it is not 100psi. I do not know what the norm is but 5psi is what comes to mind. You can rent a tester from Autozone.

I would remove the carb. Remove the bowl. Make sure gasket isn't crunched. Some carbs I have rebuilt had a washer inside between carb and bowl. I usually delete it because it doesn't look right. Someone should correct me if I am wrong....

If the vent is clogged, the float will not work correctly.

This is how I test troublesome carbs:

Now, remove float. Shake it. If it has liquid in it, replace it. Check needle. If the needle is solid aluminum, there should be a rubber gasket in the seat(bushing). If the needle has a rubber tip, there should [b:654c4848f0]not[/b:654c4848f0] be a rubber gasket in the seat. Some kits come with both needles and extra parts. Put float back in place. Do not install carb or bowl. Connect fuel line. Turn carb upside down with float upwards. Dry off needle and seat area with air. Open fuel supply. See if it gets wet. Kinda hard to do if you need the engine cranking to get fuel. You might need to connect before the pump for testing. If it gets wet around the needle, either you need a new seat(bushing mentioned in the part numbers above) or the carb has a hairline crack.

I would try gravity flow from the tank. You may need a pressure regulator after the pump to lower your fuel pressure. Hal

If it was me,
I would remove the carburetor and check for trash. Make sure the float valve seat is clean.

It is not uncommon for the fuel line to ooze and need tightening after a while, expecially if you are running ethanol gas in it. hopefully you are using worm clamps. If you are using spring clamps, The old ones won't fit the 7/16 o.d. line that is common now. The old line was 1/2" o.d.

I have a Chief 1000 and I think that when your tank gets about 1/2 empty fuel will quit flowing if you bypass the pump.

For you guys that don't know, the tank is on the grille, in front of the engine, not above it.

If you don bypass the pump, run the line directly to the carburetor, don't try gutting the pump and going through it. If you do you will probably be creating a prime condition for future vapor-lock problems.

Thanks for the directions guys. My dad should have a fuel pressure gauge. I will check that and follow up. I should add the carb was ultrasonic cleaned and the fuel lines are all brand new with worm clamps. Additionally the tank screen is new, and there is an inline filter. I will check fuel pressure and if that is normal (like 3-5psi), I will start checking for dirt. Thanks!

I checked fuel pressure while cranking the engine and it was at 1.5 psi. I then put it back together and ran it for close to an hour. No fuel leaks anywhere. Before it was doing it in a matter of minutes. It looks like it miraculously fixed itself. My only thought is because it sat for probably a month before it did this that the pressure regulator in the pump stuck and is happy again now. Thanks for the help guys.