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Rough Running, Stalling, Poor idle Consistency?
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Jefferson8Ball
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PostPosted: Sun Jul 19, 2020 2:57 pm    Post subject: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Hello Beetle People!

I have a '68 beetle that suddenly started running rough and stalling out a week back. My grandpa and his friend (one mechanic, one familiar with bugs) both were stumped.

At first I thought it was bad gas so I drained the tank/lines and replaced the fuel filter. This made no difference

I did the "look down into the carb" test, and noticed the accelerator pump injector wasn't squirting gas consistently when I hit the gas it seemed partially blocked.
So I 'express'-cleaned the carb. This DID make some difference fuel looks to now squirt properly down the carb.

It still is running rough: stalling, hesitating acceleration, and inconsistent idle.
Adjusting mixture/volume screws doesn't cure the symptoms. (If anything, they seem to have less of an affect than in the past?
Car still runs when mixture screw is bottomed out, and idle speed screw isnt raising speed much at all Normal?)

Possibly helpful info:
Aftermarket EMPI carburator.

Thanks in advance! Very helpful that this website/community exists.
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63beryl
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PostPosted: Sun Jul 19, 2020 10:04 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Stalling and poor idle, sounds like a vacuum leak. With the car running spray the carb and intake with starting fluid. The motor will rev a little if you spray an area that has a vacuum leak. You didn't state if you have a dual port motor, but the boots that seal the middle section with the two end pieces sometimes develop a vacuum leak. The throttle shaft on the carb is also a common place to have a vacuum leak.
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Jefferson8Ball
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PostPosted: Tue Jul 28, 2020 7:50 am    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Okay, it smooths out and rpms increase when I spray below the starter coil area I think. Ive been having a hard time pinning down a specific location.

Meanwhile, I was putting in new spark plugs the first 3 went in fine but the last will NOT catch threading or even catch in the hole?? It just stays loose and wont hold itself. Spent 3 hours trying to thread it by hand and with a socket.

Kinda worried that Ill have to take the engine out to get a better look and try from a direct angle, or to rethread with a tap. Id really rather not have to do that because I dont really have the means/tools to.
Any alternative ideas?
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mukluk
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PostPosted: Tue Jul 28, 2020 12:26 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Jefferson8Ball wrote:
Meanwhile, I was putting in new spark plugs the first 3 went in fine but the last will NOT catch threading or even catch in the hole?? It just stays loose and wont hold itself. Spent 3 hours trying to thread it by hand and with a socket.

Look at the old spark plug and compare it to your new plug. Does the old plug perchance have a threaded insert stuck on its threads like the picture below?
Image may have been reduced in size. Click image to view fullscreen.

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Jefferson8Ball
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PostPosted: Fri Jul 31, 2020 4:12 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

mukluk wrote:
Jefferson8Ball wrote:
Meanwhile, I was putting in new spark plugs the first 3 went in fine but the last will NOT catch threading or even catch in the hole?? It just stays loose and wont hold itself. Spent 3 hours trying to thread it by hand and with a socket.

Look at the old spark plug and compare it to your new plug. Does the old plug perchance have a threaded insert stuck on its threads like the picture below?
Image may have been reduced in size. Click image to view fullscreen.


My Grandpa had a thread tap, so he rethreaded it and got the spark plug in. Rough running issue still remains though.
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mukluk
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PostPosted: Fri Jul 31, 2020 4:19 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Jefferson8Ball wrote:
Okay, it smooths out and rpms increase when I spray below the starter coil area I think. Ive been having a hard time pinning down a specific location.

Please explain this one further or post a picture pointing to exactly where you're talking about. A change in running quality when spraying something at a specific point normally means you have a vacuum leak there.
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Jefferson8Ball
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PostPosted: Fri Jul 31, 2020 4:22 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Still not sure if its a vacuum leak. My grandpa went and bought a new distributor (seemed like a shot in the dark to me?), and no change.

This is what it looks/sounds like:

( My grandpa has his foot on the accelerator in the video, because it wouldn't stay running otherwise.)


Link




Help! We are stumped and don't know where to start.[/youtube][/url]
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mukluk
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PostPosted: Fri Jul 31, 2020 4:42 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

That engine is only running on two cylinders with the occasional misfire knocking it down to one. You need to recheck your spark plug leads that they're in the correct firing order and position, then recheck your timing.

You still haven't answered or clarified where it was you sprayed that had an effect on how the engine ran.
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Relyt
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PostPosted: Fri Jul 31, 2020 4:52 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

You generator is also not oriented correctly, could lead to burning it out early.
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Jefferson8Ball
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PostPosted: Fri Jul 31, 2020 4:59 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

mukluk wrote:
Jefferson8Ball wrote:
Okay, it smooths out and rpms increase when I spray below the starter coil area I think. Ive been having a hard time pinning down a specific location.

Please explain this one further or post a picture pointing to exactly where you're talking about. A change in running quality when spraying something at a specific point normally means you have a vacuum leak there.


Thanks for the responses, I'll have to get back to you on that. I'm going to address the spark plug leads/timing first, because I was having a hard time telling if/where the spray was having an effect. ( the bug is at my grandpa's shop, so I can't test it immediately)
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Jefferson8Ball
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PostPosted: Sat Aug 01, 2020 12:29 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

mukluk wrote:
That engine is only running on two cylinders with the occasional misfire knocking it down to one. You need to recheck your spark plug leads that they're in the correct firing order and position, then recheck your timing.


Just checked my spark plug leads and readjusted the timing.

(I set it to fire 1-4-3-2 as required, with #1 firing on the second notch of the flywheel (7.5 degrees past TDC, as suggested in Chris Vallones video: https://www.youtube.com/watch?v=787INwvir24&t=307s ). Also timed it using his method.
Also set the distributor point gap to 0.016 ", because the new dist wasn't properly set, followed this video: https://www.youtube.com/watch?v=4uEW0HJPG40&t=178s)


Crying or Very sad Mad Now i dont think its firing at all? Won't turn over, just pops and backfires..

Bad sparkplug leads/caps? Vacuum Leak still? no idea
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vamram Premium Member
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PostPosted: Sat Aug 01, 2020 12:41 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Your description sounds like the timing is still off. Check this out to make sure you're actually at TDC for the #1 and that your wires are installed in the correct location, 1-4-3-2 clockwise.

http://www.vw-resource.com/find_tdc.html
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Jefferson8Ball
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PostPosted: Sat Aug 01, 2020 11:50 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

vamram wrote:
Your description sounds like the timing is still off. Check this out to make sure you're actually at TDC for the #1 and that your wires are installed in the correct location, 1-4-3-2 clockwise.

http://www.vw-resource.com/find_tdc.html


There seems to be a lot of differing information - should #1 be timed to top dead-centre? Or 7.5 degrees, at the second notch?
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PostPosted: Sun Aug 02, 2020 12:25 am    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Jefferson8Ball wrote:
Just checked my spark plug leads and readjusted the timing.

Crying or Very sad Mad Now i dont think its firing at all? Won't turn over, just pops and backfires.

Your timing has gone from bad to worse then. You need to determine for certain where cylinder #1 is in firing position, then take note of the distributor rotor position and adjust the plug leads/distributor position to match up with that. Rotate the engine so that the left hand timing notch lines up with the case split, pop the right valve cover off, then check to see if both rocker arms for #1 are positioned so that the valves are closed (both should be even with each other and have a small amount of clearance between the adjuster and valve stem tip). If both valves aren't closed, rotate the engine exactly one revolution so that the left timing notch is lined up with the case split then check the #1 rockers again -- they should both now be closed. When both of #1 cylinder's valves are closed and you have the timing notch lined up with the case split, this is cylinder 1's firing position. Wherever the distributor rotor is pointing when you have #1 in firing position, the #1 spark plug lead should be positioned directly above the rotor and the remaining leads arranged in the proper firing order from there -- 1/4/3/2 going clockwise around the cap. Don't forget to put your valve cover back on.

Once you have all the previous sorted out, set your ignition timing statically to 7.5BTDC, which should be good enough to get the engine started and running. You can reset the timing using a strobe at full advance afterward. If your crank pulley only has two closely-spaced notches, the left notch should be 7.5BTDC and the right one 10BTDC. Post up clear pictures of the pulley timing notches if you want verification of what you have.
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vamram Premium Member
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PostPosted: Sun Aug 02, 2020 6:28 am    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

This is in his gallery. Shepherd's hook is upside down. That's the metal tube from your vacuum can to the carb's advance port on the left side.

Image may have been reduced in size. Click image to view fullscreen.

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Jefferson8Ball
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PostPosted: Sun Aug 02, 2020 7:09 am    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

vamram wrote:
This is in his gallery. Shepherd's hook is upside down. That's the metal tube from your vacuum can to the carb's advance port on the left side.

Image may have been reduced in size. Click image to view fullscreen.


Hi Vamram, thanks for the response. If you look in the video I posted above, I think youll see that it isnt upside down. That may be an old photo in the gallery, or its just cut off by the edge of the photo.
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PostPosted: Sun Aug 02, 2020 12:46 pm    Post subject: Re: Rough Running, Stalling, Poor idle Consistency? Reply with quote

Jefferson8Ball wrote:
vamram wrote:
Your description sounds like the timing is still off...

There seems to be a lot of differing information - should #1 be timed to top dead-centre? Or 7.5 degrees, at the second notch?

There is differing information because different distributors have different requirements. To choose the right method, you need to identify your distributor.

mukluk wrote:
...set your ignition timing statically to 7.5BTDC, which should be good enough to get the engine started and running.

Yes, 7.5 BTDC static will be close enough to get it running regardless of what distributor you have. These engines will run with the timing off 10 degrees or so either way, but to run well and last long, you should figure out what distributor you have and fine-tune the timing using the proper procedure for that distributor once you have the engine running.

You might want to check your compression to see if that is the root of the problem. You said the problem came on suddenly. Compression could be lost suddenly if there is a valve-train problem, a broken ring, or if the head studs are pulling out.

You might also want to verify each component of the ignition system. Is the coil still healthy? Is spark coming from the center wire to the distributor? Is spark getting to each of the plugs? Maybe one or more spark plug wires is bad.
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