Bill,
I think it unlikely that the fuel pump is at fault here. The pump
pumps in response to lack of resisitance/pressure in the fuel line to the
float bowl. At idle, there is very little fuel being consumed by the
engine, so even if the pump were weak it would provide plenty of fuel to
the float bowl. At higher revs, when consumption is greater, a weak pump
would deliver insufficient fuel and engine sputtering would develop.
Go back to the points for another look. It may be that, since you
don't drive this car much, some corrosion or oxidation has formed on the
contacts. Pull a piece of very fine sandpaper, 400 or 500, between the
points gently, check dwell and reset if needed, then reset the timing.
Another possibility is that the plastic rubbing surface on new points
sometimes wears quickly on the distributor cam lobes, thus closing the
gap in very few miles. Shouldn't happen, perhaps, but it can and does.
Do the points cleaning, dwell checking and timing exercise for this also.
This sort of low-speed stumbling is more likely to be electrical than
fuel-related. You're probably ten minutes away from having the problem
solved, which will start your new year off happily.
Bob
On Thu, 29 Dec 2005 16:53:39 -0500 William Killeffer
<wkilleffer@comcast.net> writes:
> Hi everyone,
>
> While driving my 1974 MGB recently, the engine would sputter badly
> and
> sometimes stall when taking off from a stop. The stall happened more
>
> often than not, and getting the car started again could be a bit of
> an
> ordeal.
> One side of me thinks that it could be time to replace the points
> dizzy
> cap as it's been at least a year. But I don't put alot of miles on
> the car.
> The fuel filter looked dirty, so I replaced it. But that didn't get
> rid
> of the problem.
> I've had the car just over four years, and replaced the old leaky
> fuel
> pump with a new, non-solid state SU. It makes all the right noises
> when
> I get ready to crank the starter.
> Could the fuel pump be the problem? This only seems to happen once
> the
> engine is good and warmed up long after the choke is off. I've
> watched
> the fuel filter while the engine is running, and it receives a
> squirt of
> fuel on a regular basis. The carbs are SU's and have been rebuilt
> and
> rebushed within the last two years. They don't appear to be leaking,
> and
> the dashpot oil level is where it should be.
> Any ideas or suggestions would be welcome. Frankly, I don't get to
> drive
> the car nearly enough, and wonder if that could be a contributor to
> this
> problem.
> Thank you,
>
> --
> William T. Killeffer
> wkilleffer@comcast.net
|