Help please - '80 Aircooled losing power and backfiring

[dilemma]

I need your help please as my 1980 - 2.0 Aircooled has been causing me a lot of issues recently.

On a recent trip it developed an enormous backfire - this was traced back to a very worn rotor arm, temporarily replaced the governed one with an old beetle one and it worked perfectly.

Since then I have refitted a new governed arm, replaced all of the worn HT leads. The van starts instantly and idles perfectly; but after a short 5-10 minute journey it then loses power for a second every couple of minutes and the backfire has returned.

Other than blaming my bad mechanical skills can anyone suggest the cause of such an issue? Plugs? Vacuum hose?

[dugwiththevwbug]

check the plug leads whether they need the threaded nipples on the ends of the plugs as there are two types of plug leads available.

regards doug

[HarryMann]

Have you actually treated it to a new set of plugs?

Or had them out for inspection/diagnosis (if so findings?)

Could be lots of things, but if that's a regular occurrence after first getting up to temp, maybe all is not right in the combustion chamber.

[rustytop]

Reckon you should go back to the un-governed beetle rotor arm to elimate the rotor arm issue.

Worth a try

Rustytop

[The_blue]

I never had a governed arm in mine.#

Check the timing as well. There is a very recent thread with the settings.


My arm:-
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[HarryMann]

Check the timing as well. There is a very recent thread with the settings.

That would have to be quite retarded timing to do that...

[Plasticman]

Sounds very much like a dizzy cap under load to me
mike

[The_blue]

Check the timing as well. There is a very recent thread with the settings.

That would have to be quite retarded timing to do that...

True. But how many horrors do we hear on here? Plus is it retarding right on revs? Are the weights jammed and is the vacuum working?

Backfiring could also be a leaking exhaust.

[HarryMann]

Backfiring could also be a leaking exhaust.

Yup, indeed, but on the over-run, off the gas...

[CovKid]

How old is this engine exactly? or is it as old as the vehicle?

[dilemma]

Well that might be part of the problem as we don't know exactly as its not the original engine. The previous owner had it installed but the paperwork doesn't give any detail.

However, it is now in intensive care, undergoing diagnostic treatment so we're hoping it will come out the other side alive and well (without denting out wallets too much!)

Dilemma
-x-

[HarryMann]

Its is always a good idea to try to identify the engine and any odd features (e.g. 1.9 DG with old DF heads, or.... 2.1 DJ but with carbs not injection, MV running without Cat and open-loop ECU).. of course, obvious, but you don't want a mechanic setting thinsg up thinking it's engine A, when it's a B, or even C
They usually won't have the time to find out, so willjust make an assumption...