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Full Version: Help! Rebuilt Carbs, Now Engine Car Shudders at 4k RPM
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'70PVW914
Hey folks. I just rebuilt the weber IDF 44 carbs on my 914-2.0 because I was experiencing hiccups/stutters in acceleration from idle to about 3k rpm. Also, the car would idle very low, and then die if you did not give it a good amount of revs after starting. I figured my idle jets were clogged, and since the carbs had not EVER been rebuilt, I re-gasketed, and rejetted them.

Just finished that today, put in new fuel line to the carbs, changed the fuel filter, and troubleshot a strange problem where my accelerator cable seemed to wrap its way around the clutch cable and bind. :headbanger

After all of that.....my car is STILL acting very strange; in some ways things are better, and in some, things are worse!

NOW:

The car seems to idle just fine at a very nice 900rpm after adjusting the idle and throttle body.----SWEET!

The accelerator cable seems to stick slightly, also, the ball joint for my accelerator pedal seems to keep popping off of the pivot point (Is there a trick to this, or is the ball joint just shot?!) Seem to have it on there now, but now guarantees! ---LESS SWEET

Still seems to stutter when reving in gear b/w idle and 2.5k rpm...same as before I rejetted and cleaned dry.gif

Shudders and looses power at 4k rpm in every gear...this thing had crazy power after 4k before I messed with anything. mad.gif

When I replaced the float needles and seats that came with the rebuild kit, I noticed the seats were way smaller on the rebuild. I DID NOT adjust the float level....my first culprit for this less than stellar performance. After reading some posts on here, it sounds like the float should be at between 12.5mm and 13mm from the upper face of the carb. Would this solve these problems?

Also, I DID remove the throttle valves for a clean and inspection when rebuilding...I am hoping this is not the root of the problem, as they do not seem as smooth as they once were.

Don't think its the resize in jets, as I just changed idles from .45 to .55, and air corrections from 200 to 190 as per recommendation.

Where should I start here!!!????? I figure I will measure and adjust the float tomorrow, after I remove the carbs again (damnit). But if that doesn't work...what should I be trying?.....Damn weber book didn't get here in time and I am not the most patient.....
ThePaintedMan
4K indicates something more towards the top-end of the carb. Is it possible you put your auxiliary venturies in backwards? This is very easy to do.

Yes, the floats absolutely need to be adjusted correctly. But not likely that is what's causing your issue, IMHO. Your settings should be somewhere around 11 mm with the gasket already in place and 32 mm dropped (without any tension).

IPB Image


You mentioned that you removed the butterflies, correct? Did you remove the throttle shafts? Also, do you notice any binding, and are the butterflies closing completely on both barrels? You can check this by shining a light down them and looking from the other side to see light (when the carbs are off the car and drained of course).


If we could get a picture of the carbs, that might help with any immediate visual confirmation. We'll get you sorted out.

You mentioned that you're not patient. Sorry, but owning a car with carbs, especially a 914 is going to require plenty of that. Nothing is going to get fixed all-at-once unfortunately. We've got to work through each issue systematically, but in the end you'll have an awesome reward for being patient smile.gif
wndsnd
Not an expert on the carbs yet. Mine are brand new so other than rejetting them I haven't messed with much.

I do understand that ball socket popping off. I am going through the same thing right now. I ordered one from the bird at $14.00 plus shipping which seems to be the going rate unless I missed some secret source.

They have a fairly fragile c-cllip inside that snaps them onto the ball. If I could find some at a reasonable price I would have a 1/2 dozen to keep around.

I just found a thread last night by McMark that had a picture of how he mounts his clutch clevis pin. If it goes in the wrong way there is a lip that catches on the throttle ball socket and pops it off.

I know I was getting some of that action. But I am back to work (slowly I will admit) and won't be able to play again till next weekend.

John
Razorbobsr
QUOTE(wndsnd @ Nov 11 2013, 08:04 AM) *

Not an expert on the carbs yet. Mine are brand new so other than rejetting them I haven't messed with much.

I do understand that ball socket popping off. I am going through the same thing right now. I ordered one from the bird at $14.00 plus shipping which seems to be the going rate unless I missed some secret source.

They have a fairly fragile c-cllip inside that snaps them onto the ball. If I could find some at a reasonable price I would have a 1/2 dozen to keep around.

I just found a thread last night by McMark that had a picture of how he mounts his clutch clevis pin. If it goes in the wrong way there is a lip that catches on the throttle ball socket and pops it off.

I know I was getting some of that action. But I am back to work (slowly I will admit) and won't be able to play again till next weekend.

John
Safty wire the acc ball joint. Bob
rhodyguy
confirm the throttle plates are installed with the degree number, like 5*, visible from the top and the beveled edges are in the correct orientation.

after re-jetting you got started with going to the pre-install setup procedure, yes?



'70PVW914
So, in order to sync the carbs, I need to get a synchrometer. When this arrives will be the next time I take out the carbs to address the float level any other problems before reattaching them and properly synching.

In the mean time, I want to figure out what these other problems could be potentially....

[/quote]ThePaintedMan Posted Nov 11 2013, 05:48 AM
You mentioned that you removed the butterflies, correct? Did you remove the throttle shafts? Also, do you notice any binding, and are the butterflies closing completely on both barrels? You can check this by shining a light down them and looking from the other side to see light (when the carbs are off the car and drained of course).\

My friend recomended we not touch the throttle valves, and of course I insisted we take them out and clean them. Did not remove the shaft, but the way the throttle valves went on , they had a lot of play in how they sat on the shaft.

[quote]rhodyguy Posted Nov 11 2013, 06:52 AM
confirm the throttle plates are installed with the degree number, like 5*, visible from the top and the beveled edges are in the correct orientation.

after re-jetting you got started with going to the pre-install setup procedure, yes?


Just for clarification. the numerical stamp on the butterfly valves should be facing into the engine? or upward into the top of the carb? The LAST thing I want to do is score the inside wall of the carbs....BTW, after putting almost 15 hours of work into this project, patience is something that wears thin.... but I will always have patients for this car..... she's my baby.

wndsnd AhA! C-Clip ordered, temp fix safety wire!

Thank you all for your input. Will let you know if I have any more questions.

stugray
I am local.
Work in Boulder, Live in Longmont.
If you stopped by I could have a look for anything obvious or throw a snail on it.
I even have a WB AFR, but for it to work you need a "bung" welded in somewhere.

I have a weber carbed 2.0L on premises we can compare to.
I just rebuilt my dual 40 IDF webers as well.
rhodyguy
i misspoke with the degree number i guess. at least with this set. to clarify a bit...both edges of the plate have a bevel, with the shallow edges of the bevels being the closest to the venturi when the plates close. wider carb pict shows the opening aspect and carb orientation for the other pictures. the bevel picture is shown with the bottom of the carb pointing upwards. the degree (78*) mark is on the side of the plate with the longer edge of the bevel. all 4 plates must be installed commonly in the correct orientation. time consuming, edit edit edit, and hard to explain in text and be clear. takes about 2 minutes in person.

buy the cb book and get a synchronizer like the one pictured.
ChrisFoley
QUOTE(rhodyguy @ Nov 12 2013, 08:33 AM) *

i misspoke with the degree number i guess...

I believe it says 78 Kevin.
rhodyguy
edit. too early.
'70PVW914
QUOTE(stugray @ Nov 11 2013, 08:47 PM) *

I am local.
Work in Boulder, Live in Longmont.
If you stopped by I could have a look for anything obvious or throw a snail on it.
I even have a WB AFR, but for it to work you need a "bung" welded in somewhere.

I have a weber carbed 2.0L on premises we can compare to.
I just rebuilt my dual 40 IDF webers as well.


PM Sent!
'70PVW914
Ok guys....bad news. I woke up this morning psyched to adjust the float needles on the carbs and synch them, and I discovered that a piece of the plate that holds the pivot needle for the float is broken and is no longer holding the float pivot in place!

I am so frustrated! I am now wondering if these carbs are just clapped out... Does anybody have any suggestions, or any spare IDF 44 scraps? Could I JB Weld or something to just hold the pin in place for now to get the car running? Should I just buy new carbeurators?.....I really cannot afford this right now!

Heres some pics of the one that is broken piece:

Click to view attachment

Whats the damage here......
'70PVW914
That was a joke about the jb weld....
wndsnd
I hope you found the piece in the bowl...
brant
I actually have seen and used in weld in different gas application. There are some products that are better for fuel. There is also a helicopter certified alloy welder in longmont that I have used to weld motorcycle carbs before.

Don't give up!
brant
You might even be able to safety wire that
Dr Evil
Is that not an integral part of the float? Get a new float, should be available, and do it right wink.gif Way to stick to it and find the/an issue, though.
euro911
It's a broken split tab, Mike - but repairable.

Maybe more expensive than having a bung welded into your exhaust confused24.gif ... but I bought e of these 'portable' exhaust clamps for my AFR. You need to install an O2 sensor in it, but you can move it from car to car quickly idea.gif

Innovate Motorsports Exhaust Clamp - P/N: 3728

Click to view attachment

Available directly from Innovate (Click here)

or Summit Racing (Click here)

I added a long spring to it so it won't fall off while driving smile.gif
Dr Evil
I am used to mikuni, bing, etc, where that piece is easily replaced. Looked integral in the pic. So, the float bolts to the tab?
Dr Evil
Ya, a new float will have that tab. This is what I am talking about.
ThePaintedMan
That's a very common problem with Webers. Those ears for the float pivot pin are very fragile. I bet you could take the top to a radiator shop though and have them zap it real quick to weld the broken piece back on - it's aluminum.

Or you can get on the phone with Pierce Manifolds in California and they'll probably have a 44 top that they'll sell you fairly cheap.
rhodyguy
is this the set you were sent to replace the first ones? 44 bodies yes? this really sucks mike. you could try ACE too. common? dry.gif

k
euro911
On Webers, the tabs that the float pivot rod slides into is cast in the carb top.

This shows the missing portion of the tab

Click to view attachment
'70PVW914
Thats the spot....theres also this, i posted to the classifieds post as well.


...some nasty looking sheering of metal where the throttle linkages attach....are these carbs still usable, or should I stop dumping time and money into them?

Click to view attachment
Dr Evil
QUOTE(euro911 @ Nov 17 2013, 08:13 PM) *

On Webers, the tabs that the float pivot rod slides into is cast in the carb top.

This shows the missing portion of the tab

Click to view attachment

Doh, I looked right past that to what looked like a missing tab on the float. I see. Yes, now all the other recommendations make sense. smile.gif

Weld it, not a prob.
ChrisFoley
The broken leg is a bit too delicate to weld back on, but a good aluminum welder can build up the remaining leg so a fresh hole can be drilled.
I wouldn't bother trying to reproduce the split though.
'70PVW914
QUOTE(Racer Chris @ Nov 18 2013, 04:59 AM) *

The broken leg is a bit too delicate to weld back on, but a good aluminum welder can build up the remaining leg so a fresh hole can be drilled.
I wouldn't bother trying to reproduce the split though.



Thanks man, this sounds like the most viable option! Gonna take it to get welded tomorrow....shouldn't be but a few sheckles i'd imagine.

After that I'm all set with new gaskets to do the valve adjustment, clean out my heater boxes, the carbs and the float adjustment, then sync and tune! Goal is to have her purring in my driveway by this sunday! Looks like I may even get a day of skiing in before then! Living in Colorado totally sucks! laugh.gif
brant
be careful where you take that for welding

its a delicate part and takes a little skill or experience.
the muffler shop on the corner is not a good idea
ChrisFoley
QUOTE(brant @ Nov 19 2013, 08:11 PM) *

be careful where you take that for welding

its a delicate part and takes a little skill or experience.
the muffler shop on the corner is not a good idea

agree.gif agree.gif agree.gif

Whoever does that really needs to already have experience doing buildup on tiny aluminum objects.
Its so easy to overheat that little thing and melt it into oblivion.
It may cost up to half an hour of labor.
brant
There is a certified aluminum welder in longmont...
the guy (as mentioned previously) has helicopter certification
he is absolutely amazing....

I've had him weld pot metal carb bowls previously.
sure its 5-10 bucks higher... but not screwing around and done right
cheap compaired to a new set of carbs!

b
stugray
Dont know if blurry pics help but this is a view of your problem:

IPB Image
Wish I had a pic of the float on to show how much room you have to work with.

More pics of carb rebuild in that folder.

http://s366.photobucket.com/user/stuartjgr...914_build_carbs
stugray
Any luck?

Something I forgot to mention. I stumbled across my aluminum solder rods last night.

You could build up that area with Aluminum solder and then redrill that hole.
If it doesnt work, that just means you couldnt get the solder to stick, so no harm done.

It would be nice to try on something other than the real part.
somd914
Not sure if you've been able to get your float leg repaired yet, but I went through the exact same break. My son has a friend who welds as a hobby - did a nice job.

All I asked for was a weld, I'd grind and drill. He did it all including a media blast, and dropped it off at the house for no charge - guess there is hope for the younger generation!

Click to view attachment
'70PVW914
Hey folks,

Got the repair done to the pivot leg and it looks great....
Click to view attachment
not as great as yours somd914...but functionally, it will work just fine and is a very strong weld! Had a friend of a friend who makes bicycles and did it for a 6-pack!

Have the new accelerator pumps on and floats adjusted! Just waiting for the warmth of tomorrow to properly seal up the valve cases after completing adjustment (yes!), do an oil change, put on the carbs and fire her up!

Hoping for the best!
euro911
Very good thumb3d.gif
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