Weber 32/36 Adjustment

[heyman421]

I got my 32/36 Installed today, and i'm having some issues fine-tuning it.

The tuning instructions describe leaning out the idle fuel mixture until the idle worsens, then richening it in 1/4 turns until the idle smooths out, becomes worse again, and then finally placing the mixture 1/2 way between the two points for your 'best setting.'

I made it so far as leaning it out until the idle started to drop and become rough, and then right around 1/2 a turn richer speeds the idle up as fast as it will go (at any given idle speed position) but then subsequent counter-clockwise turns make zero difference.

My problem is that as soon as i richen the mixture to the ideal idle, it already has a faint smell of richness. It seems like it goes from lean to rich almost immediately.

If this is normal, i appologize. I'm fairly ignorant with regards to carburetors, or gasoline engines in general. I learned to drive, and have subsequently owned only diesel vehicles, and am just paranoid about messing something up.

I just got a tune-up. Plugs, wires, distributor, and timing were all done by a professional mechanic.

The only vacuum line is the distributor advance, the evap system is plugged, and i'm using a vented cap in it's absense.

Just looking to draw on others experiences installing weber carbs to see if i'm alright. Thanks.

[synack7350]

how far out are you turned total on your mixture screw (the point where it starts running good) also where is your idle screw? to really dial it in you need to set your idle screw really low to the point where the truck is running just good enough to here the differences you make in mixture screw adjustments. if you are out more than 2 turns on the mixture screw you need to rejet to a bigger size (go in .10 increments) the jets are easy to change and cheap to obtain from weber. I bought a variety as my mixture was to lean for my elevation. this way if I travel (as I'm apt to do, I'll always have spare jets for different elevations). if you need a bigger primary jet then you might as well get some secondaries too.

[heyman421]

I'm only +/- 1 turn from the neutral 2-turn out position.

And then smell is definitely rich, not lean. I think the jet is ok.

I'm going to give it a nice long highway burn today, and tweak it a bit afterwards to see if perhaps i just fouled the plugs a bit.

[synack7350]

yeah its just important for tuning to not exceed that as you get into the secondaries, so the mixture screw will lose its responsiveness and it wont allow for an optimized idle, you'll also have crappy throttle response. I know cuz I drove on it with undersized jets for about 2 weeks waiting on the proper jets to come in the mail. been all over the place with the mixture and idle screw. with .80 jet on the primary I'm at a perfect 1.5 turns.

[heyman421]

I think i nailed it this afternoon.

I finally figured out my throttle cable was a little sticky, so the truck wasn't even at a proper idle when i was trying to adjust it.

Now i've got it idling around 700rpm, with the fast idle around 850rpm, and the exhaust just has a faint 'exhaust-y' smell to it. Maybe just a hair towards rich when the choke is engaged.

The weber drives a little different than the factory carb. It's definitely got fewer 'dead spots' than the hitachi did, but they're in different parts of the power curve which is taking a little getting used to. Also, i've never heard anyone else mention it here, but the weber seems to be a little less linear with regards to throttle response than the hitachi. The weber is very torquey down low, most of my city driving can now be done around 15-20% throttle with ease. Also, it seems that fairly substantial hills require only a 5-10% throttle adjustment, which makes the truck feel really light. As far as at-speed acceleration, however, there seems to be a huge gap between 20% and 60% where 15-20% seems to be all you need to maintain highway speed, and 60%+ has very nice pull, but variations from 20-60% or so do NOTHING! I hear the engine change note, and i'm sure it's sucking in more fuel, but it's very difficult to modulate your cruising speed for lane changes or passes by simpling rolling your foot, or a little toe-tap. You have to bury it to 60% or so, and then back off to 20% again once you get to speed.

As a whole, however, the truck feels much lighter and more responsive, and while the truck still doesn't idle 100% smooth, it's more a constant vibration than the sporatic missing and shaking i got with the hitachi. This engine (z22) has a bad habit of dieseling on shut-down if you raise the idle high enough to be perfectly smooth, however, so i suppose it's just the nature of the 30 year old beast.

[heyman421]

Just another small note.

Fixing the sticking throttle was a simple matter of attaching a $2.50 throttle return spring between the throttle cable holder and bottom lip of the air cleaner. I checked to make sure nothing was binding, that it had nothing to do with the truck (cable, pedal, etc.,) and that the throttle shaft nut was just hand tight. It seems that the internal throttle return spring isn't pretensioned quite enough, and while it does a fine job of snapping the throttle shut from half-throttle or more, there just isn't enough tension to return to idle from partial throttle.

[synack7350]

yeah they send you a doo hicky to mount to the carb base for a return spring (but they don't provide the spring).