Advice please - Rapid backfire and misfire

[VAN with a PLAN]

Hello, hoping some of you can help. My van has been a joy to drive of late, particularly since winding the mixture screw out a touch at the MOT last month.

Today it died on me unexpectedly and refused to start, the symptoms would imply fuel starvation, which I have suffered on the odd, random occasion. My usual trick of removing the supply line from the carb and sucking some fuel through the pump resulted in an instant mouth full of fuel - yuk! Not a supply issue this time then.

I did some quick checking of HT leads, distributor etc. and eventually it started and idled nicely. 5-10 minutes down the road it began to backfire rapidly and was hesitant and misfiring. I was only 5-10 mins from home kept the revs up and nursed it on. After a few minutes it cleared and was pulling nice and cleanly and running well. 2 minutes later it's back to backfiring rapidly and running poorly.

Having parked it up for an hour I went back out and gave the connections another quick look over, nothing obvious. The van starts on the button but needs throttle to keep running, is running poorly and the revs drop even with a fixed throttle position.

Has anyone experienced these symptoms? I can't find anything that exactly matches this in the Wiki or Tech Archive.

Advice gladly received!

Thank you
Peter

[marlinowner]

Mine behaved similarly when there was water in the petrol tank, when I drained some from the tank into a glass jar there were two clear layers.

[VAN with a PLAN]

Interesting, that could be a relatively easy fix. Thank you.
Does that mean I would also have water in my float chamber?

[kevtherev]

Interesting, that could be a relatively easy fix. Thank you.
Does that mean I would also have water in my float chamber?

Yes.

[kevtherev]

Also check the idle speed cut off is working.

[VAN with a PLAN]

Thanks Kev and Marlin. I wanted to get to this sooner but life keeps getting in the way!

I picked up a new fuel filter and replaced it while draining some fuel from the tank. The fuel was clear but there did appear to be a few droplets of water on the bottom of the jar. The fuel I drained out of the filter however was distinctly hazey.

It fired straight away but was really rough for 30+ seconds, it then cleared and has been running beautifully ever since.

Thanks again for your replies, they're always greatly appreciated.

I guess now I have to work out how water is getting in and put a stop to it!

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[kevtherev]

Usual suspects are perished breathers

[VAN with a PLAN]

Thanks Kev.

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