Fuel Issue

[Ian F]

Anyone out there in Stagland help, I have a niggling issue that I can't seem to cure.

Car starts and runs like a dream, and if I stop to fuel up or nip in the shops, come out and she'll start again - no bother. Equally if left for 3-4 hours or more and she is totally cooled off, again she will start and run, no problem, but it is that "in between" timeframe when I've stopped for 30 mins to 2 hours.


She will start up fine and tick over as normal, but as soon as I go to pull away, I lose all power and it is as if I lose 4 of the 8 cylinders. I am unsure whether it is one carb flooding, although I have replaced needle jets and set float levels etc., or whether it is fuel evaporating and causing the misfire? If I dip the clutch and rev her up to clear the misfire, it does clear and then runs as normal. Sometimes there is a slight smell of fuel suggests flooding, but nothing from the overflows (and 28 mpg overall) suggests this is not the issue. Other times no smell of fuel and it can suffer a similar misfire/hesitation when very hot - NO, not in this country and only once or twice.


It frustrates me, but otherwise runs fine. Only other issue is how do I replace the dash pot seals to stop losing the oil? Have removed the needles, but cannot see how to remove the adjuster to replace the seals? Any ideas? Anybody help?


Ian F
P.s Jason I don't want a Weber - no disrespect to V-Mad or anyone who has one!

[martin]

Hi Ian, to change the O rings, remove the piston (air valve) unwind the adjustment, remove the grub screw, pull out the needle, then with a soft drift, drive the needle holder up the tube, then the dog can see the rabbit, when ordering the O rings, get new sprag washers as well, not worth the risk of using the old ones, when replacing the sprag washers, use a drift that's a good fit in the tube so as to drive it home square. Martin.

[Firept]

Ian.
Could also be the "O" rings at the end of the coffins (temperature compensator) part numbers 516971 and 516972. they decay over time.
Paul.

[Ian F]

Martin/Paul

Thanks for the suggestions, but Martin how tight are they? I have tried to remove them, but they did not budge! How hard are they to move? Will have to try harder - sounds like a school report?

Thanks again
ian F

[stag157.7]

Martin/Paul

Thanks for the suggestions, but Martin how tight are they? I have tried to remove them, but they did not budge! How hard are they to move? Will have to try harder - sounds like a school report?

Thanks again
ian F

remember you are drifting from the bottom (needle end) towards where you put the oil in

alan

[DJT]

And use a length of thin dowell wrapped in fine emery paper to dress out the scratches made by the sprag washer when removing the existing seals before pushing the new ones in, otherwise you could tear the new o-rings.

[tjk]

Hi
My guess is fuel evaporating in hot engine bay, I had same symptoms,I rerouted fuel line away from any heat source and this cured the problem.

Regards
Tim

[Ian F]

Alan/Dave/Tim
Many thanks for all your comments and ideas, I was trying the right way, just possibly not hitting it hard enough? I have got a spare set of carbs, so I'll use a little more force.

Does anyone know which type of fuel line will resist the heat best, plastic, metal braided or what?
Thanks
ian F

[Stagsongas]

Hi Ian,

I've no wish to throw a spanner into your works (what a great pun!) but I might have a useful idea for you. I have read your post as a lurker but now I'm legitimate (a matter of opinion!) I can offer my thoughts. I've only had my car 6 weeks and already it is displaying very similar symptoms to yours, but with one important difference - mine now runs on LPG so the carb.s have a lot less (but not nothing) to do.

My car seems to malfunction just like yours, as if one bank went down, and it will even stall at idle but it does not do this from cold or thankfully when driving, it does it when it has been left hot and becomes heat soaked. If it is restarted within 30 min.s or so I get the same, failure of some cylinders although in addition, the merest touch of the throttle will stall it dead. I had a heck of game getting it into the garage tonight after a run and rest. For one reason or another (later) I don't think it's a carb. fault at all, I think it is a fault with the Lumenition CDi unit.

The way I approach these things is to come uo with a theory and then prove/disprove it. My Lumenition unit is placed where most seem to be, up on the bulkhead. It's a hot place to be with heat rising from the NS manifold. When the engine is stationary there is little or no airflow to disipate it, so it rises by convection instead. Striking whilst the iron was hot (another great pun!) and the engine running badly I got my IR thermometer out and drew a back spot on the aluminium Lumenition unit to get an accurate reading. I found that my car misbehaves when the CDi unit is at 55C, but when cooled to 23C later on the engine runs like a dream once more. Of course, just having some temperature readings like these does not mean I'm on the right track, it could just as easily be a heat related problem with the carb.s, say fuel vaporisation, but you have to start somewhere. So, whilst you are follwing the carb. route I'll follow the CDi idea.

How will I prove or disprove? I'm going to rig up a computer chip cooling fan and strap it to the CDi unit heatsink. It will run all the time the engine runs. I'll measure the difference in temp. of the unit, hopefully that will reduce with the fan, and if that coincides with an improvement it will show I'm on the right lines. I will let you know how I get on in the next few days. In the meantime, good luck with the work on your carb.s

Regards

Steve

[wilf]

I can tell you now that hot HT coils also play up. Took me 3 to find one that tolerated the heat.

[Stagsongas]

Wilf,

Anything electric or electronic has an ideal working temp. range. If outside that, and normally when over temp, resistance of compontents, along with other effects can put it out of action. So, I agree, the coil could be at fault too, and on the Stag this is not ideally placed for cool running.

Regards

Steve

[DJT]

The way I approach these things is to come uo with a theory and then prove/disprove it. My Lumenition unit is placed where most seem to be, up on the bulkhead. It's a hot place to be with heat rising from the NS manifold. When the engine is stationary there is little or no airflow to disipate it, so it rises by convection instead.

Hi Steve,

Welcome to the forum. I can see some excellent exchanges of views, and some new input being very welcome here....

Have a look at the following pictures. One is pre refurb, the other post refurb. Apart from the obvious differences in paint, etc, there is one major change...............

DSC01593a.jpgDT0189a.jpg

[Guest]

I had a similar starting problem a couple of years ago.It turned out to be the temperature compensators attached to the carbs.I replaced the small o rings and then adjusted the nylok nut that holds the bimetal strip so it was just seating against the body.Problem solved.I hope its something as simple as that, and you don't even have to remove the carbs to do it.
Anthony

[KOY 23]

Hi Steve,

Welcome to the forum. I can see some excellent exchanges of views, and some new input being very welcome here....

Have a look at the following pictures. One is pre refurb, the other post refurb. Apart from the obvious differences in paint, etc, there is one major change...............

[ATTACH=CONFIG]22358[/ATTACH][ATTACH=CONFIG]22359[/ATTACH]

You've photoshopped your Luminition module?

[DJT]

You've photoshopped your Luminition module?

I'm not that clever John. I moved it inside the car and fitted an excellent 2nd hand bulkhead pad acquired from Martin Dimmick to replace the one butchered by the moron who fitted the Lumenition originally.