Clogged Idle Jets Caused By Cheap Air Filters! The Best Fixes for Weber 40 IDF Problems

[@JeffreyFukushima]

The bumper falling off when you turned the ignition caught me off guard. I went from thinking about carburetors to uncontrollably laughing at myself for watching the video. That said, I'm saving this video for future reference due to your extensive knowledge on the subject. Thank you for reminding me to RTFM.

[@GarageTimeAutoResto]

Thanks for the reminder. That made me laugh too....was a while ago

[@cagr4249]

Sadly it is common to underestimate the importance of excellent air filtering! And this is not just limited to customers/laymen but is also found at worldwide selling vehicle brands...(my qualification in this topic: working nearly 30 years in this field at a "premium" car/bike-brand)

[@GarageTimeAutoResto]

Thank you for sharing! Clean air is essential

[@Antarath]

That cold start at 16:00 is just like me cold starting my 68 beetle equipped with a single Empi HPMX carb. 2-3 cranks. On the 3'rd it starts but dies right away. On the 4th it starts and runs but won't idle until it's warm so I have to rev it for half a minute until it's warm enough. Why no choke, EMPI?? I did not install this carb myself. I wanna toss it in the garbage. On top of it all the previous owner installed a 009 distributor without vacuum. The positive thing is that now I'm sort of forced to learn more about the car, it's engine and components and how to fix things and eventually get rid of/or fix these things. Also, since I'm a newbie at this, I must point out that there might be a reason why the no choke carbs have these 009 distributors that I'm unaware of. Still learning.

[@GarageTimeAutoResto]

This took a bit longer to start because the fuel bowls and passages were empty. Normally it starts on first crank after pumping the pedal three times. I still need to keep it running with the pedal for the first 30 seconds. Like you said there is no cold start valve or choke.

[@Zincaloom]

It is amazing that dust and dirt can find it’s way in there. Hope that fixes it. Nice job.

[@GarageTimeAutoResto]

Exactly, it's clear to me at least that this dirt didn't come through the fuel supply.

[@jimfloyd7606]

Another good tip. Prior to installing the carb top gasket/s coat each side with grease. This will aid in trapping dirt. And lightly coat the top/bottom sealing surfaces of the filters with grease.

[@GarageTimeAutoResto]

I think I did this? Was in the video no? If not then I agree with you 100%

[@Djinantonek]

I have the cast aluminum filter housings on my Dellorto 36mm DRLA carbs on my 1600 VW type I engine. Very rigid. One thing that I did was put gaskets under the velocity stacks. I saw light under the stacks which I felt, if light could get through there then air could get in. I didn't want any air bypassing the SK Syncrometer. I watched all of your 911/12 video series and greatly enjoyed it.

[@GarageTimeAutoResto]

Thanks for watching. I'm sure those cast aluminum versions are much better when it comes to sealing. Good idea on the gaskets under the stacks. Well done!

[@neilbardsley]

Thank you. I'm chasing clotted idle jets on my webers. This has given me something else to look at

[@GarageTimeAutoResto]

I haven't had a single problem since I added these snorkel tubes and filter gaskets

[@neilbardsley]

I had the carbs off today and they were pretty clean

[@GarageTimeAutoResto]

It doesn't take much to clog the little idle jets. Only a .5mm hole that things can stick to.

[@neilbardsley]

@@GarageTimeAutoResto just had to clean an idle jet again. I've bought some. How did you mark where to drill the hole in the gasket and base of the air filter?

[@1ocean515]

Nice walk through of the issue, and your approach to solving the problem, Tom. I lived in Alamitos Beach/Belmont Shore for 14 years, and I can attest to the amount of very fine debris that is kicked up on the Boulevard there. Im sure that is true farther south. As temperamental and precise as Weber’s can be, the poor fit of the air cleaner certainly needed addressing. I hope your fixes solved the problem! 👍👍

[@GarageTimeAutoResto]

Thanks. The next step is to seal up some of the extraneous holes in the engine bay. It doesn't help that there's no oil tank there. Some debris gets in that way too. Also some of the electrical panel holes should be plugged up.

[@AW_DIY_garage]

Very cool video, sorry you are having problems. I don't know why but I laughed when you brought out the tiny ballpeen hammer, so tiny. I wrote this comment BEFORE you mentioned the tiny hammer, came back to edit after you mentioned it... lol

[@GarageTimeAutoResto]

Ha ha, It lives next to my BFH😀

[@SuperishMario]

My 40 IDF's are currently being rebuilt and should be done Friday! Hoping it solves my 912 running and idling issue! Great content keep up the good work!

[@GarageTimeAutoResto]

Great, fingers crossed for you. Share your jetting, chokes, and engine detail😀

[@SuperishMario]

@@GarageTimeAutoResto Will do!

[@SuperishMario]

@@GarageTimeAutoResto 50 idle, 50 pump, 115 main, 200 air, F-11 e-tubes, 28mm venturi are the specs! Some where saying to upgrade to the 32mm venturis to gain 10/12 hp

[@GarageTimeAutoResto]

Thanks for sharing ! I hope it runs great for you. Report back when you get them installed. You have a pretty lean setup so monitor engine temps and knocking when under load.

[@SuperishMario]

@@GarageTimeAutoResto Will do! What is the ideal set up for you? I was hoping this set up would help the motor run cooler. Maybe there is something I should be doing different?

[@asicerik]

Very interesting Tom. I love me some vintage, but I don't miss carbs!

[@GarageTimeAutoResto]

My 911 engine will be fuel injected 😎

[@arturochavez3134]

love the video but fyi that linkage sux you should look into a CSP LINKAGE its simple you set it warm and you forget about it they never get out of sync and less moving parts

[@GarageTimeAutoResto]

I'm not sure those work on 912 engines?

[@walterkucharski4790]

I had the same issues on my Webers. I installed a Racor 5 micron canister filter and no more issues for 4 years except for clogged filters. I washed the tank and fuel system before installing the filter. When the filter cloogs the rpms drop the I swap it and keep going. Good luck.

[@GarageTimeAutoResto]

Same, my fuel tank and surge tank inside the tank are very clean as is the stainless fuel lines to the back. I don't think this dirt came from the fuel supply or through the filter. 10 micron is pretty small. The idle jet is 500 micron for a point of reference. The needle clearances are probably less.

[@jockellis]

Gonna have to look at my one remaining Solex 40PII-4 to see what it looks like. Hate to admit it but despite taking the Zeniths from my Super and Solexes from my ‘64 SC and ‘68 912 apart I never figured out how they worked until a few months ago when the carb on my Harbor Freight lawnmower got a dirty bowl.

[@GarageTimeAutoResto]

I kinda like carbs. Fun to study and figure out, but at some point it's just old tech.

[@chuckdegenaar8764]

Precision Matters sells an adapter to allow original air filter canisters to mount on Webers. With the tooling you have available you could probably manufacture one as well

[@GarageTimeAutoResto]

Thanks Chuck. I'm aware of his filter adapters at $170 a pair. That plus $250 or more for oem air cleaners and it's just more than I want to spend. This engine will only be in my car for 3-4 months and the new 911 engine will be fuel injected.

[@CrispysProjects]

Interesting, thanks for the info, I look after a 914 on Weber 40s, without a choke cable. How is yours starting compared to pre cleaning? We seem to pump the gas 12 times pre start pre Dyno/linkages setup( still hard after) but I've never had the carbs apart to check jets ect. Something nice about old carbs👍

[@GarageTimeAutoResto]

It starts right up. In this video it took a while to fire, but that's because the carbs were full of air. Check that the accel pumps are actually shooting gas down the throat.

[@CrispysProjects]

@@GarageTimeAutoResto good shout, I know they do squirt but not sure how even. She's had lot of work before us and slowly working though stuff, think a carb strip down is also on its way 👍😃

[@GarageTimeAutoResto]

Gotcha, gotta rinse those gremlins out of there!

[@Hangin_With_Shane]

Interesting issue and fix Tom! How's the sanding going...ha ha ha?

[@GarageTimeAutoResto]

Thanks Shane. Haven't even started, but plan to tomorrow. It's been warm here so it's hard to get out there

[@janeblogs324]

Nylon is like the 2nd hardest plastic, it won't compress. Remember this is the biggest vacuum cleaner, the tiniest gap will suck dust

[@GarageTimeAutoResto]

That is why there is a thick EPDM gasket above and below the nylon spacer. You think I'm trying to use Nylon as a gasket? Hmm, maybe you didn't watch the video😧

[@vintage76vipergreenBeetle]

I would have made the idle vents a little bit longer and also added a vents to the fuel bowls.

[@GarageTimeAutoResto]

It might come to that? But let's hope the air cleaners will do their job first.

[@vintage76vipergreenBeetle]

@@GarageTimeAutoResto Did you spray the inside of the air filters?

[@GarageTimeAutoResto]

Yes, with the K&N oil. There's another oil that is supposed to be better, but I don't remember the name

[@cocos.]

Hi Tom, The stracks are very high for the los filters

[@GarageTimeAutoResto]

I was thinking the same thing. What height would work better?

[@jeffharrison5265]

Great trouble shooting and diy fix.

[@GarageTimeAutoResto]

Thanks Jeff, I'm reasonably confident this will work😎

[@johnrodgers6049]

What was the original symptom? Was the car idling poorly

[@GarageTimeAutoResto]

The car had a sporadic idle and some of the idle mixture screws didn't respond at all. It's been a long time and the idle has been super steady ever since I did this mod.🙂

[@johnrodgers6049]

I have a 66 Alfa Romeo GTV with Webers with similar issues. Will look into it.

[@openhighwayproductions]

Must likely the reason many folks do not use carbs anymore due to foreign particle infiltration and associated running issues being unresolved.

[@GarageTimeAutoResto]

You're right. They are finicky, but when they're right they're awesome!

[@RobPhillips-n8y]

Check the air filter for loose rubber that wasn't trimmed. It can be sucked off and work it's way into the idle circuit . Trim with a razor and enjoy the rest of you drive.

[@GarageTimeAutoResto]

Cool thanks and good tip. I haven't had a single issue since adding the snorkel tubes.

[@lancemillward1912]

Trouble free motoring...or as Trouble tree as you can with a vintage car

[@GarageTimeAutoResto]

Let's hope so. I plan to do a drive tomorrow.👍

[@GregariousAntithesis]

It has zero to do with your air filter i is likely the fuel tank has corrosion issues you didn’t see and the alcohol gas is a huge contributory problem. Also alcohol fuel breaks down certain rubbers and especially plastics. Go through your fuel system from carb back and replace any fuel line with alcohol compatible fuel line.

[@GarageTimeAutoResto]

Already done! I did a complete fuel system overhaul here on KZbin. My fuel tank has a surge tank with a pre filter inside the tank. Then it goes through stainless fuel lines and ethanol rated hose. This dirt wouldn't be on top of the carb body if it came from the fuel supply.

[@GregariousAntithesis]

@@GarageTimeAutoResto well it doesnt make sense your whole theory about air jets. Air comes in the large hole or holes then fuel is mixed into the air flow coming in via the high and low jets At the Venturi. It has to be coming from your fuel system somewhere, air never can get into the float bowl unless the body of the carb itself were warped beyond belief and then you would have fuel leaking out everywhere.

[@GarageTimeAutoResto]

Thanks for your comments and I'm open for a healthy debate. The fuel bowls are definitely vented to atmospheric air through the top of the carb. If not, as fuel is consumed from the bowl it would be under vacuum which is bad. The idle circuit works very similar to the main circuit. It has an air correction jet at the top of the carb. This air is emulsified before it gets dumped into the main throat of the carb. Check out the little blue arrow in this diagram. It's air. www.huskyclub.com/Porsche40IDA3CWeber.html