Jerking Beetle problem - Advice needed

[Manninyf]

Hi guys,
So i am the owner of '78 1600L beetle and today while taking a polite drive my beetle decided to start jerking violently as i pulled off from an intersection.
I managed to crawl it home (was like 100m away) but my beetle wouldn't accelerate without violent jerking.
It idles fine, and i can rev the engine fine when it's in neutral. It also reverses without jerking.

Any ideas or thoughts as what the problem may be??

thanks

[Sambabus]

Have you told it you love it?........my split bus is super sensitive.

[vwpumagt]

Sounds like fuel starvation. Check fuel filter first.

[retrovan]

Bowden tube, broken or loose, or incorrectly fitted.



Hi float level, due to sticky or dirty needle and seat.

Herman

[Cyberbeast]

Does it have almost no power? If so, I need to ask the stupid question, but is it running on all 4 cylinders? If one dies, my Beetle will still sound semi normal at idle, but when driving it will shake violently, especially under acceleration.

[1964type1]

You may have gunk in the fuel tank blocking the outlet. Also check where the fuel hose attached to the tube coming out of the chassis, going into the engine compartment runs. If it is too close to the exhaust it heats up and causes the fuel to boil. I had this issue on my 64. Also check the fuel filter for blockages.

If the above is correct you may have dirt in the carburettor, blocking off the jets as the vehicle moves and shakes the fuel in the float bowl around.

It is important to start at a point and systematically work your way through.

[retrovan]

.......
It idles fine, and i can rev the engine fine when it's in neutral. It also reverses without jerking.............

This sentence makes me think the its not a fuel thing, but a clutch thing, such as Bowden tube, engine mountings, gearbox mountings.......

Se maar net.....

Herman

[Manninyf]

Firstly, thanks Retrovan, 1964type1, cyberbeast and vwpumagt for your advice, it was really helpful.

So i also suspected it wasn't a fuel thing because it fed fuel perfectly when idling and reversing without jerking.
I had a friend, who is more knowledgeable with older cars than I, come see it (i am kind of learning on fly when it comes to my beetle).
And he out out of interest sake just cleaned the connections in my distributor and now my 'daisy' is riding fine again. I don't know if this would have been expected but the violent jerking most certainly didn't feel like cylinders which aren't firing which normally gives a heavy side-ways shudder and not violent jerking.

But alas, thanks again peeps

[JohanSmith]

Hi guys

I am having the exact same thing after replacing my clutch cable today. I replaced everything the same way it came out, but the shudder stays horrible. Please help.

Cheers
Johan

[retrovan]

Hi guys

I am having the exact same thing after replacing my clutch cable today. I replaced everything the same way it came out, but the shudder stays horrible. Please help.

Cheers
Johan

Did you remember to bend the Bowden Tube to about 25 mm, It must NOT be strait.??

See 1st photo above, you will see how it must be bent, then also check your engine mounting as well as your gearbox mountings.

Herman

[Vick]

Firstly, thanks Retrovan, 1964type1, cyberbeast and vwpumagt for your advice, it was really helpful.

So i also suspected it wasn't a fuel thing because it fed fuel perfectly when idling and reversing without jerking.
I had a friend, who is more knowledgeable with older cars than I, come see it (i am kind of learning on fly when it comes to my beetle).
And he out out of interest sake just cleaned the connections in my distributor and now my 'daisy' is riding fine again. I don't know if this would have been expected but the violent jerking most certainly didn't feel like cylinders which aren't firing which normally gives a heavy side-ways shudder and not violent jerking.

But alas, thanks again peeps

Had the same, cleaning points sorted it out.....

BUT my problem is not sorted completely and hope you guys can advise on a few things.

All I know is that my Beetle is possibly 1972 and 1600cc. From what I could get thus far, there were 3 power options, 57hp, 60hp and 65hp version of the 1600cc. Is there a way to determine which one I have? Engin number start with SFBRxxxxxx (ID plate indicate Model as 114, serial starts with 1102, assembled in SA by VW SA)
Speedo still in Mph
It still have a Solex carb (30 Pict 1) with Oil bath air filter, single port.
Reason for wanting to know is that it seems that the timing is different for each.
57hp 0 deg. ATDC (They talk about a "B" case")
60HP 5 deg. ATDC ("AD" & "AE" case)
65HP 7.5 deg. BTDC ("T" case)
65HP 0 deg. ATDC ("U" case)

On the crank pulley there are 3 "Vs" cut into the top of the pulley closest to engine. I assume one will be for TDC and the other two for 5 deg. and 7.5 deg BTDC. The 2 markings close together are to the right of the single mark.

Thx in advance for all the help.

[Dawie]

You have a 1970 singleport. DIN-Bhp rating 47hp, SAE rating for same engine, (in tiny "American ponies"), is much more.

Dual port 1600 engines were 50 Bhp.

Published specs about ign timing often refers to USA-spec emission controlled vehicles, and does not apply to "rest of the world" models.

The mark on the right should be the one. Timing for early single port engines were 10 degs btdc, and later ones 7.5 degs btdc.

The 30PICT carb singleport engines came with the short fat distributor which had the big vacuum can. Those distributors are vacuum only, and the 30PICT carb has special little ports/channels inside them to provide the specific vacuum signal those distributors require.

[SLIMZ_ZA]

Clean out the heat risers, my 72 done the exact same, got a cable attached it to a drill and slipped into the heat riser and slowly let the wire spin occasionally reversing the direction and the amount of carbon built over the years chunks came out, took a compressor and blew it out and that fixed it in fact it ran better, more power, huge difference

[73type2]

Good advice, even though the last post was seven years ago!