Dolly SE slight mis-fire

[eveshamcroft]

Took my SE out for spin (from Bridlington) to Flamborough for lunch at the Rose & Crown Saturday. Hint, go with a good appetite as their portions are HUGE !!
Anyway thought we would take a ride to Filey along quiet side roads. Car began to "chunter" at about 30mph pulling up a slight incline in top. Dropped into 3rd to give the engine some revs and she seemed ok. But then it ocurred a few more times always when pulling hard in top. Getting a little worried, I turned off to the main Brid - Scarboro' road reckoning if she failed at least I would know what the road number was when I called for assistance. However, I gave her some stick - well 50 - 55 mph which is fast enough in a non o/drive 1500 and got back to our bungalow in Brid ok. At tick over engine is smooth as silk at about 600 rpm.
My thoughts are maybe some crap in the petrol tank blocking the fuel intake. Car has only done 34500 miles since new so tank could have some rust floating about in it. I will get it back to Leeds in August and get it to Vermont Classics at Yeadon and get them to remove tank and clean it out. I cannot undertake any jobs on my cars now - getting on a bit!!!

Has anybody any other thoughts as to the cause of this little problem?

[triumphdolomiteuk]

Try unscrewing the float chamber lids and seeing if there are any bits of crud in there, that'll give you a clue as to whether any rust from the tank is being pulled through. Is the vacuum advance working ok? Condensor ok? Points ok? Coil ok?

[dollyman]

I had the same on my 1850 auto a few weeks ago. I got home and could not find anything wrong apart from i thought the oil was low in the dashpots (strombergs) there was oil in them..... But i topped them up a bit.... Never missed a beat since I could not say it was that? But them problem has not returned.

Tony.

[cleverusername]

I had the same on my 1850 auto a few weeks ago. I got home and could not find anything wrong apart from i thought the oil was low in the dashpots (strombergs) there was oil in them..... But i topped them up a bit.... Never missed a beat since I could not say it was that? But them problem has not returned.

Tony.

That would make sense, on an SU that is the equivalent of the accelerator pump which temporarily enriches the mixture. No oil would mean too lean a mixture under hard acceleration.

[eveshamcroft]

ought not to be points etc as car has a Boyer Bransden electronic ignition unit. Going to Bridlington this coming week end so will check out float chambers. I did try to remove plugs but they have probably been in for 38 years and would not budge (when hot) . Will spray some WD40 on to the plugs in the hope it penetrates down into the threads but as car performed ok at speed, it can't really be plus / points, does really seem like crap in the tank blocking fuel intake.

[mahony]

If the plugs have been in 38yrs then I would say the plugs could be at fault, also I used to have a boyer bransden electronic ignition fitted to my sprint in the early nineties, the one I had fitted was a little black box with red/green led's fitted on the top, this unit retained the points and was supposed to generate a bigger spark