Club 80-90 Forums

Hello,

Driving yesterday I found the van started to splutter and surge, first at around 55mph, but progressively worse so that it started to struggle a bit moving off. Worst of all was constant part throttle. Occasionally it would clear altogether.

If you pumped the accelerator it would overcome the issue, suggesting to me it's a bit lean, and the pumping overcomes this temporarily.

So thoughts are:

Air leak (can't find one)
Fuel filter (new tank and filter fired by PO)
Fuel pump not keeping up (new brickworks one on it)
Little filter in the carb inlet (clean as a whistle)

In case its ignition related
Timing well off (to check still, but dizzy hasn't moved)
Ignition model (brand new one fitted)
Plugs/leads etc (new set fitted)

So now I'm thinking its one of the many little vacuum pipes round the carb, so will check them next

Any other cunning ideas??

Without changing any settings, do a complete regasket of the carb after blowing the jets through and cleaning.It could be a split accelerator diaphram or even a sticking needle valve, and they will be in the kit anyway

Also well worth checking the vacuum advance on the dizzy. Sounds very much like the problem I had a few years ago (particularly when warm) and I pulled my hair out trying to work out the issue. Changed the vac uni and been fine since. Its possible to change the unit without removing the dizzy.

Yes good point. Remove pipe connected to dizzy at carb end, remove dizzy cap then suck hard on pipe and see if base plate below rotor arm moves. It may just need oiling or vac unit may be kaput.

This sounds pretty close to a thread I have open at the moment - only mine won't even generate enough oomph to move the van without dieing; http://forum.club8090.co.uk/viewtopic.php?f=37&t=165091

Do let us know what your issue turns out to be, just in case I'm suffering the same/similar issue; it'll give me somewhere else to look

I'm currently rebuilding the carb; couple of issues found, but I'll find out in the next couple of days what ails mine (and whether or not it is/was the carb blocked).

Thanks all.

Dizzy advance works fine.

Minor air leak found, the vacuum temp sensor in the air box is knackered. Is the flap in the air box set to have hot or cold air when it's shut - I.e. Do I just plug the vacuum line or do I join the two lines together and bypass the temp sensor part?

Will pop it off and give it a clean out next.

Well whilst sorting out the various vacuum lines I noticed that the king plug lead wasn't of the same type as the others.

Reason soon became clear, the coil was of the pin ended type, but the new dizzy cap that had been fitted was of the non-pin type.

So the old pin ended lead had been wedged in, but it doesn't make good contact and hence the arc has almost gone through the copper end of the lead.

Screwed the pin end off the old lead and onto the new lead that was in a box of spares handed over with the van.

Now both ends fit, will see if it's made much of a difference in the morning. Can't see it having been helping though.

Its these accumulative problems that can add up to one big one though

Due to sickness testing was delayed until this weekend. Did 60 ile trip out.

Combination of new vacuum lines, a good blast of carb cleaner and the replaced king lead has led to a much smoother running van, with the hesitation all gone.

Carb is still filthy though, so I think a rebuild is on the cards shortly.