Need some advice from the carb experts, Weber IDF 40s Options

[bondo]

As you may know, I bought a 914 last week, and it came with barely functioning Weber IDF 40s.

Well I got the first one apart, and here is what I found:

Main jets: 115
Air corrector jets: 200
Idle jets: one 45 and one 50
Float valve: 175
Main venturi (choke tube): 28
Aux venturi: 4,5
Emulsion tubes: F11
Accel pump jets: 50 FW
Accel pump bleed back: 55

There was enough crud and rust that I have opted to go for the full rebuild. The float valve had visible wear, and the accel pump diaphragm looked kinda wrinkly and messed up. One of the idle jets was missing its o-ring, and one accel pump jet had 1 extra washer.

Obviously one of the idle jets is wrong, does the rest of this sound ok for an engine that is probably a 1.7 or 1.8? The PO said it ran good and got good gas mileage before it got all clogged up. One air bypass screw was about 1/2 turn out, the other was completely closed (and rusty)... perhaps because of the mismatched idle jets?

[lapuwali]

Everything there looks about right, except for the idles. 50s are common.

[bondo]

QUOTE (lapuwali @ Oct 6 2005, 08:10 PM)

Everything there looks about right, except for the idles. 50s are common.

Cool, thanks. Bug shop for that too?

[Joseph Mills]

QUOTE (bondo @ Oct 6 2005, 08:56 PM)

As you may know, I bought a 914 last week, and it came with barely functioning Weber IDF 40s. There was enough crud and rust that I have opted to go for the full rebuild. "Jets" Bug shop for that too?

Full rebuild kit is a good choice.

Your various components sound like a good place to start (after correcting the mis-matching and missing pieces).

And to eliminate hidden maladies, you might want to fit fresh spark plugs and adjust your valves. Also insure your timing is correct.

After your rebuild, using your Weber manual, spend some time with adjustments and sync them. And then adjust and sync some more. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Chances are, WOT will be fine. But for stages with mild throttle applied (which is what aggravates you when not working right), check the manual for correcting these problematic symptoms (this is kinda the tougher part).

Keep posting your progress.

Oh, my local Sand Rail shop sells jets for 1/2 the price of the Bug shop, which are 1/2 the price of the P-shop.



..

[Joseph Mills]

I just read the title to your thread.

You got any big grains of salt? (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

..

[bondo]

QUOTE (Joseph Mills @ Oct 6 2005, 10:21 PM)

I just read the title to your thread. You got any big grains of salt? (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif) ..

Strangely enough, I think that's what was clogging my idle jets! (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

I do intend to do plugs/points/cap/rotor. I'll do a valve adjustment if I have any trouble tuning the carbs. I was going to try to hold off on the valve adjustment until I got some heat exchangers to replace the rusted out ones on it now. (a little less stuff in the way will be nice)

[Joseph Mills]

QUOTE (bondo @ Oct 6 2005, 11:28 PM)

Strangely enough, I think that's what was clogging my idle jets!  :D I was going to try to hold off on the valve adjustment until I got some heat exchangers to replace the rusted out ones on it now. (a little less stuff in the way will be nice)

I'm pretty salty, but I don't think that is mine. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Having just gone thru this process, do the valve adjustment NOW, the more loose ends you can eliminate, is a real good thing to do. (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/hijacked.gif)

I'm still chasing an on throttle "hesitation" with my almost perfectly performing "cam'd" and "carb'd" 2.0 L.

It's not stuttering. It's more like sputtering (momentarily). Where's the Captn when you really need him? (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

But back to you...

I have some idle and mains you can borrow for tuning if you would like to have them. Just send the mailing address and what you want.

All I want is a ride in that '59 when you score.(IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

..

[bondo]

QUOTE (Joseph Mills @ Oct 6 2005, 11:00 PM)

I have some idle and mains you can borrow for tuning if you would like to have them. Just send the mailing address and what you want. All I want is a ride in that '59 when you score.(IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif) ..

I'm not going to mess with jet tuning (I hope). The PO said it ran good, so I just intend to rebuild them (with matching idle jets) and adjust the screws until it runs the best, and then drive it. Every day this car isn't driving is another day I have to get around at 11.5 MPG. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

As far as the 59 goes, you got it! Heck, I may even get it to your neck of the woods, as a route 66 road trip is on the list of things to eventually do.. and I can't think of a better car to take. (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif)

[SGB]

Joeseph-
I had part throttle stumble from my 40 webers. Try adjusting the air bypass screw to provide more air to the mix. After you open those up some, you will have to readjust the mixture volume screws too. This leaned out my idle / low-speed circuit and made for easier transition to main jets. My 2 liter likes about 31/2 turns out from the bottom for those air corrector screws, which is pretty lean. If you get it too lean, besides reduced performance, it will overheat.
Royce-
really gotta agree that a good valve adjust is a must have to get those carbs cooperating with each other. Otherwise, the two banks of cylinders will fight each other as combustion occurs out of exact sequence.

[bondo]

QUOTE (SGB @ Oct 7 2005, 10:17 AM)

Royce- really gotta agree that a good valve adjust is a must have to get those carbs cooperating with each other. Otherwise, the two banks of cylinders will fight each other as combustion occurs out of exact sequence.

I'm a little afraid of adjusting the valves.. the engine seems a little TOO quiet to me... and it was rebuilt by a shop specializing in vanagons. It may have hydraulic lifters, and I've heard that things break if you adjust hydros to solid lifter specs. I'm hoping to find out exactly what went into this engine, as I now work at the shop that rebuilt it. I'm just waiting for the boss to find enough free time to check the archives. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Anyone know of an easy way to test for solid or hydraulic lifters?

[Aaron Cox]

Royce,

pull a rocker assebly, and then fish out a lifter... youll know if its hydraulic (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[Joseph Mills]

QUOTE (bondo @ Oct 7 2005, 10:46 AM)

As far as the 59 goes, you got it! Heck, I may even get it to your neck of the woods, as a route 66 road trip is on the list of things to eventually do.. and I can't think of a better car to take. (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif)

We have lots of good Rt66 roads left.

(IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif)

[Joseph Mills]

QUOTE (SGB @ Oct 7 2005, 11:17 AM)

Joeseph- I had part throttle stumble from my 40 webers.  Try adjusting the air bypass screw to provide more air to the mix.  After you open those up some, you will have to readjust the mixture volume screws too.  This leaned out my idle / low-speed circuit and made for easier transition to main jets.  My 2 liter likes about 31/2 turns out from the bottom for those air corrector screws, which is pretty lean.  If you get it too lean, besides reduced performance, it will overheat. Royce-

Thanks Royce. I will include that process with my other tuning efforts.

The carbs are back on the car now with only preliminary adjustments made.

I've been waiting to get my EGT senders/gage installed before proceeding with tweaking.

Hopefully this weekend... (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)