We have an 18 hp. twin fuel pump on the side of the carb . It was
working fine and then quit . It appeared that it was lack of gas as it
would start and run as long as you pored the gas in the carb . I
rebuilt the fuel pump and it still wasn't getting fuel . I took the
top off the carb and it was bone dry . I replaced the needle valve and
it still didn't get fuel . This time when the carb was apart I pored
some gas in the bowl and pored gas to the fuel pump line doing it
several times and turning it over to prime the pump . When I put the
carb back together it started right up and ran good . I took it out to
try mowing with it an again after about 10 minutes it acted like it
was starving for gas . Then it stalled again . Same problem . The fuel
pump seems to be powered by a vacum hose coming up from the
crankcase . Is there anything in the crankcase (filter)or something
that would plug up ? I can feel som air coming out of the hose when I
turn it over . I can suck fuel out of the gas line at the fuel pump
connection from the tank...Any ideas...Rick
I don't screw around - I go to NAPA and get a low pressure electric fuel
pump and install that. I haven't had to remove the old diaghram pumps yet -
but when the tanks are low and in the rear I mount the electric pump back
there. The one I installed a couple weeks ago I ran from the light switch
that was no longer used so I can shut it on and off. Others I have right
from the ignition switch.
I just put one on a 18 HP Briggs twin on a 1984 Agway (Murray). I have one
on a 1960's 70's Sears Suburban 16 HP single (Tecumseh). And I put one on a
1980's Sears twin that I sold. As I said above, my nephew also uses them.
That pump works off of alternating pressure and vacuum from the
crankcase. They do not develop much pressure at all. I've never seen a
pulse line get plugged. When you rebuilt the fuel pump did you clean
every speck of the old gaskets off? I usually run a flat file over the
pump body and cover lightly several times to make sure it is clean and
flat. The thin rubber diaphragm goes against the body, then the gasket,
then the cover.
Check the pickup in the bottom of the tank, many have screens, and clean
as needed. If there is an in-line fuel filter replace it with one from a
small engine shop. Do not use an automotive or paper type fuel filter.
That pump will not develop enough pressure to get the fuel through it.
Also check the fuel line. If it is cracking at the ends or is soft and
squishy, replace it. Also check that the fuel cap is vented.
You are on the right track. Good luck.
Thaks for the info, The filter came from Laser Sales (a small engine
supply ) It is clear plastic and the filter media inside looks like a
GM filter (the small ones that go in the carb . I can suck gas through
the line right from the connection at the fuel pump . I light sanded
the surfaces to make sure I had everything . I wasn't aware there was
a pickup screen in the tank . I will check on it . I certainly acts
like the fuel is being restricted . Rick
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