Stall on idle, occasional high revs plus backfire

[Merrsh1]

Hello

First post to this brilliant forum. Long time lurker and consumer of knowledge!

I have a 1980 2 litre air cooled engine which will turn over and only idle with application of some revs, as soon as the revs are removed the engine stalls. While idling with the revs applied it will occasionally backfire and sometimes the idle speed of the engine becomes quite high. Any attempt to engage gear and move results in an immediate stall...

The van has been running fine for months. Recently (more than 100 miles Ago) had a full service with new fuel filter, oil, new fuel lines etc. Drove the van last week no problems.

Can anyone give me some pointers of what to check. I'm loathe to get the AA out as I want to resolve this myself but need some advice to do so.

One thing to mention - A friend recently fitted a stereo for me and mentioned running the stereo without the engine running may damage the coil. I forgot about this and had the stereo on whilst cleaning the van today. Could it simply be ive fried the coil? Research on this appears to suggest this isn't the case but I mention it as a possible cause!

Thanks for reading

[multisi]

Is your stereo wired up so you have to turn ignition key, best to install without needing key. Remember to turn off stereo .

[Merrsh1]

Is your stereo wired up so you have to turn ignition key, best to install without needing key. Remember to turn off stereo .

Yes it is but it runs on the accessories position.

[Merrsh1]

Figured out what the problem was in the end so hopefully this may help some other poor sod...

Loose vacuum hose on the right hand carb.

[danmetallic]

I was about to say it sounds like a vacuum issue. Glad you got it sorted.

[Merrsh1]

This has kind of 'reappeared'.

The vacuum hose came loose again the other week and reproduced all the same symptoms of the first post on this thread.

So I attached a jubilee clip to keep it in place and thought problem solved. Went camping yesterday and on startup the van now runs really rough, almost like it's really labouring. However there is no backfire...

After a while it resolves itself and runs fine. However, after an initial rough start, say 10 minutes, the van seemed to lose power for a while, completely gutless in third and fourth. I pulled over, turned off the engine, turned it back on and all seemed fine!

Went to startup this morning and it ran rough again, gave it a few revs and drove off without any problem. I'm not one for ignoring an obvious problem as it will inevitably manifest itself in some horror show / worst possible time so if anyone can shed some light or provide some pointers I'd appreciate it.

[jrt]

Plenty of info on these sort of symptoms if you search the various threads on here, here's what was causing my problems https://club8090.co.uk/forum/viewtopic.php?f=37&t=147654" onclick="window.open(this.href);return false;
David

[Merrsh1]

Plenty of info on these sort of symptoms if you search the various threads on here, here's what was causing my problems https://club8090.co.uk/forum/viewtopic.php?f=37&t=147654" onclick="window.open(this.href);return false;
David

Cheers, I've read so many forum posts that I'm going dizzy. I suppose the thing with these engines is that one issue can always have 10 possible causes...

I'm certain its the inlet manifold elbow being loose. I'm going to add another jubilee clip so its gripped both ends.

In a related issue - I think the reason the manifold inlet hose comes loose is the vibration of the engine just shaking it loose. How much vibration is normal?

[danmetallic]

Plenty of info on these sort of symptoms if you search the various threads on here, here's what was causing my problems https://club8090.co.uk/forum/viewtopic.php?f=37&t=147654" onclick="window.open(this.href);return false;
David

Cheers, I've read so many forum posts that I'm going dizzy. I suppose the thing with these engines is that one issue can always have 10 possible causes...

I'm certain its the inlet manifold elbow being loose. I'm going to add another jubilee clip so its gripped both ends.

In a related issue - I think the reason the manifold inlet hose comes loose is the vibration of the engine just shaking it loose. How much vibration is normal?

You may need some new engine mounts and a bit of turning done to stop the vibration. Some is v normal.