I know the floats are correct. The "gurgling" I heard could have been the fuel boiling. It was really hot outside when I took it out.

Tom, I usually just back a idle jet out a little while the engine is idling. If no fuel getting through the rpm will remain steady. If idle is working as it should there will be a little change in idle smoothness.

Good idea, I will try that before taking them back off

40 ida
 

hey, i right now am just getting my 40 ida car tuned up just rebuilt the motor 3.0 twin plugged,964rs cams,headers,the whole motor was gone thru, i am running a hpv-1 ignition carb specs are 36 vents,165mains,f-26 e tubes,55idle,180 air corrector,this tuning process is very time consuming but i am getting closer,anyway be patient and look at it like a huge learning expirence

Pulled the mixture screws and sprayed carb cleaner through them, they are clear. #2 and #4 cylinders are dead. I pulled the plugs and swapped them out and still nothing. Tomorrow I will swap the wires just to eliminate those as the issue.

Try Rusty's recommendation about backing idle jet holders loose, this will quickly tell you if fuel is getting to the mixture screws...it will also tell you if fuel is even getting to the idle jets.

Perform the "Hidden Gallery" procedure per my post #19.

Insulators are strongly recommended also.

Just to make sure I do this right... Loosen the idle jet holders while the engine is running and see if fuel comes out?

When engine is idling, loosen the idle jet holder. When tight the idle jet is seated and all fuel to the progression circuit and mixture screw is directed through the idle jet. When loose, the fuel can bypass the jet and flow in a much greater volume to the progression/mixture circuit. Obviously, this increased fuel flow will affect idling smoothness, if there is no effect then fuel is most likely restricted from getting to the idle jet or the idle jet is blocked with debris.

Ok, so I let the engine warm up a bit and then pulled the idle jet holders. No fuel came out of any of the idle jet holders, even when I removed them completely. I squirted some carb cleaner through the hole and cleaned the jets just yo make sure they were clear.

I did the spark plug wire swap and it definitely isn't spark related.

ideas?

Should I go back and recheck the float height?

The idle jet holders were to be loosened, not removed. If loosening did not make any difference in idle speed/smoothness and removing them also made no difference then check the idle jet for blockage of the hole with debris and if it is clean (look through it at some light) then check Hidden Gallery per procedure I provided link to in Post #19.

Sorry, my mistake. I was looking for fuel to come out not a change in idle. I will check that tomorrow.

1Quicks has given several good pieces of advice in this thread - did you do the one above first?

and you are doing all this with the 2 sides of linkage disconnected aren't you?

up to around 3000 rpm, you engine runs on the idle circuit - not on the mains - so spend you max effort on getting the idle circuit right

Mike Pierce of Pierce Manifolds (weber guru) says "idle screws 3/4 to 1-1/2 turns out" ..."anything else signifies a need for jet change "

Richard Parr of PMO published a how-to yrs ago - says the same thing ( i have that old document - about 3 pages) (doesn't seem to be online anywhere)

as above, the throttle plates need to be nearly closed - then you adjust everything else

the engine should not run at idle if the idle screws are closed

begin - set your idle screws at nominal 1-1/2 turns and then adjust the idle stop screws (plates) to get 1200 rpm or lower

then readjust the idle screws to lean best, then readjust the stop screws to reduce the rpm, and do all this over & over again until you have nearly closed plates & a decent idle in the above screw range

(get Pierce' weber tuning book - go to pierce manifolds .com)

IDA idle passages are notorious for getting clogged, and the procedure for unclogging has been addressed above and in many other threads

"gurgling" ? - 1. did you drill those carbs for anti-percolation ? (use PMO fixture) , along with installing insulators as mentioned above?

go here Weber CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT

and here Porsche 40IDA 3C Weber

also here for tons of guidance https://www.google.com/search?q=weber+ida+tuning&ie=utf-8&oe=utf-8

.

Webers
 

Well, pulled them off, squirted out all passages again (everything was clear or at least squirted through). Did the hidden passage thing, reassembled them, put them back on and.... Wait for it...

FIRING ON ALL CYLINDERS!

Haven't taken it out yet but it is firing on all 6 cylinders and it obviously running better.

Thanks to everyone for their help.

I have a part throttle miss that developed suddenly but runs fine at WOT... going to follow the steps here later this afternoon I hope. Imagine it must be an idle jet...

Piece of dirt on tip of idle jet.

Read "Sources of Debris in Float Wells"

https://paul-abbott-hu7l.squarespace.com/config#/pages|/troubleshooting

Hi Paul,

I'm going to work on the car a bit today finally. It has been awhile and I'm a visual learner... still have the original PMO type-writer instructions. Do you have any pictures to describe the idle jet clearing procedure?

Thanks,
Andrew

Sorry, web site needs picture up-loads and more words but I got tired of it and haven't finished it out.

Idle jet holders have idle jets that slip into the hollow screw portion of the holder. Pull jets out look through them toward bright light. If blocked then blow air through jets from the end with the split legs. Then look through the idle jet toward the sky or bright light to visually see they are clear. This is it for the idle jets. If car was running OK then suddenly began to have low speed running issues then blocked idle jets is most probable issue.

It would be good to review the info regarding "Air Filters and Intake Manifolds" on my web page: Performance Oriented Also, follow the link in that discussion to the "Advanced Procedures" web page entitled "Improving Sealing Efficiency Of Air Cleaner Housings" for more info regarding debris in your carbs.

I summarized the two above in the info on this web page: http://www.performanceoriented.com/troubleshooting/ entitled "Sources of Debris in Float Wells".

Hi Paul,

Feel free to use these if you see fit:

http://forums.pelicanparts.com/porsche-911-technical-forum/872492-brief-pictorial-idle-jet-cleaning-weber-40-ida-3c.html

-Andrew