Weber Help

[82Laredo]

Is the fuel return working?

I went ahead and put a one in/one out filter on it to delete the return since the weber doesn't need it, or so I've read. When I first put on the weber I was having fuel feed issues. Two new fuel pumps(after the first was bad) and a new in-tank pickup/filter to replace this:

 

[numbersix]

Your description of the port sounds like the correct "S" port which provides ported vacuum. You should have either 0 or very little vacuum on that port at idle.

 

[82Laredo]

Ok. I'll check it with a gauge next time. If it shows significant vacuum I'll look into the linkage. Thanks!

 

[jdulmer]

I went ahead and put a one in/one out filter on it to delete the return since the weber doesn't need it, or so I've read. When I first put on the weber I was having fuel feed issues. Two new fuel pumps(after the first was bad) and a new in-tank pickup/filter to replace this:
View attachment 17785

I have no return on mine. Wow! That pickup filter, or absence of one, looks bad..



"Libertatem Aut Mortem"

 

[Neuner]

I'm running the vacuum advance off the small port facing the valve cover, which has vacuum at idle. I'll try bumping the timing to see if that helps. Where is the port on this thing that doesn't have vacuum at idle?

Ya, I agree with numbersix. Mine loves that 8-9 BTDC. Any higher or lower and it really doesn't like it. Mine might have even acted like yours when it was lower but it's been too long, I forget. I also run off of port vacuum. Mine doesn't like manifold at all.

 

[Neuner]

Saw your other post about timing but thought I'd throw this in here. This is the timing/advance curve plot I did on my engine. I think it was before tweaking but can't remember. I thought maybe some of the readings/numbers might help?

The yellow is my timing with the ported vacuum and centrifugal combined. The pink is the timing with the vacuum disconnected and centrifugal only. The light blue is the vacuum pressure reading vs rpm.

 

[82Laredo]

That does help, even with the ported vacuum it still reads at idle and looks like your at about 12in of vacuum by 800rpm. I'll compare mine to this tonight. Thanks!

 

[82Laredo]

At ~600 rpm I'm reading 10in vacuum and 15in by 800 rpm. We have company over so that's as far as I got.

 

[82Laredo]

Finally got a chance to work on it for a bit last night. Pulled the plugs and they looked pretty good, except for some variation between them in color, but none I would consider too rich or lean. Went ahead and replaced them for some autolite 985's gapped at .035, which have a longer reach into the combustion chamber than the ngk's I was running.

I took off the threaded metal cap on the vacuum outlet to the left of the "s" port and checked vacuum there. Shows zero at idle so that rules out the throttle blades being open to far at idle (so there is a difference between the two ports).

I bumped the timing to 9 degrees and hooked up the vacuum advance to the port on the left and capped the other.

Results: it runs a lot better, idles much smoother due to less advance, an will pull up top now. It still had some hesitation in that last 10% throttle but smoother and no popping. I guess it's time to get some jets to fine tune it.

 

[82Laredo]

Got the jet kit and turns out it was lean. Both main jets were 145's from the factory, went up to a AMC 150 on the primary and 155 secondary. It's running great, takes less pedal to run 60mph in 5th gear and no hesitation up top unless you slam the pedal down.