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Having changed fuel tank, distributor, fuel line, and coil the car is still losing power after accelerating up gentle hills eventually stopping altogether. Left for a minute it then starts again. Having replaced all these parts hoping for a cure any ideas are welcome.

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mike -

 

I'm no super-guru on such problems, but . . .

 

Seems to me that losing power uphill is NOT

a petrol supply problem, as there is enough

of a reservoir in the float chambers to cover

such a possibility.

 

Losing power when the engine is under load

may well come back to the strength of the

spark - and that (likely) comes back to the

condenser.

 

AlanR

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Back to basics I think:

 

Compression check

If using points etc, then check condition of points, set gap, consider fitting new capacitor

Timing check

Float level check

Mixture check.

Plus

Is it overheating ? is coolant up to correct level ?

 

Bob.

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You've changed the fuel tank,have you tried running the car with the fuel cap open to make sure there isn't a vacuum forming ? "Left for a minute (vacuum disapates ) and the engine can be started again".

 

Mick Richards

Edited by Motorsport Mickey
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Thanks for the quick response the distributor has electronic ignition both new from the distributor doctor, compression ok water level fine not overheating.

I will try new plugs and running with fuel cap open. all the parts changed in effort to cure this problem which occurred just before we planned to go to the European meeting in Italy.

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Hi Mike,

have you been playing with the carbs. If the mixture is too weak then it may lose power when under load.

 

When I got my 4A on the road in 98 my needles were far too weak. They were OK at tick over and little load but heavy load killed the engine.

 

Roger

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No. What colour are the plugs after labouring uphill.

 

Take it for a run up your hill and then Kill the ignition before allowing to go back to low revs. and then check the plugs.

 

You may have developed an air leak in the inlet manifold.

 

roger

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When did this problem start?

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Problem started 4days before due to leave for Italy last September. Car broke down - started by changing fuel pump and pipe lines with new ethelene proof ones as the first ones looked to be disintegrating, then tried new distributor leads and coil mounted on inner wing,and then noticed the coating on the fuel tank was beginning to flake off. Several people told me they had problems with tank lining treatment reacting to modern fuel so changed the tank for a new steel one. We took the car out first time this year for a run of 50 miles or so last Sunday - it ran well. Took it out today only got 4 miles same problem back.

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I'd look around the fuel pump again and after. If you have a chance get a cheap electric fuel pump and connect it directly to the fuel line (bypassing the mechanical fuel pump) and to the battery and go for a spin. Where is (are) the fuel filter(s) located? Have you blown the carbs jets ?

Edited by Geko
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+1 for Geko.

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Check the bowl on the fuel pump to ensure that there is not a lot of rubbish sitting there. Under load, such material can be sucked upwards and can block the gauze, so cutting the fuel supply to the carburettors.

If rubbish present, clean it out, and keep checking, as more may come down the pipe from the tank for quite some time.

Ian Cornish

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Fuel filters can collapse internally, looking normal from the outside. If you have one before the pump, I'd remove it; there's a strainer in the pump and you can place a filter between the pump and the carbs (e.g. filter-king with pressure regulator etc)

Hope you get it sorted :)

 

Adey

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It might be a small bit of crud blocking a jet tube/needle when the engine is working hard. Rev it up and clamp a hand over the SU mouth, this will lift the piston fully and hopefully suck out the offender.

Peter

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Next time it Happens jump out and open the fuel filler cap it may not be venting, try driving with it just open to be sure.

Chris

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Have had a likewise issue a couple of years ago with a Spitfire. Starvation issues started while heading of to to the boat for crossing the channel to spend a vacation in the UK.

I found the carb-bowls to be empty at such an occurance. It appeared to be crud in the fuelline between the tank and fuelpump.

The shortterm remedy was to blow the fuelline twice a day from the engine bay towards the tank. At least this saved our holliday trip but due to the petrol moister because of the multiple hose disconnections, one of the rubber wishbone bushes colapsed. While cleaning out the tank afterwards, apart from crud I also found a small spanner in it from the PO.

Btw it all seem started after adding some octane booster, perhaps that clogged up with another residu.

Maybe you still have an intruder inside your supply routing?

 

Robert

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Hi Mike,

 

A few people have mentioned the fuel tank breather and you mention that you changed the tank, although possibly after you started having problems. Not sure if you have a 4 or a 4A, but just be aware that at some point a change was made to switch from a breather tube (connected to the top of the tank with a banjo bolt) to a breather hole in the filler cap. Most of the new tanks I've seen rely on having the breather hole in the filler cap. However if you have an early filler cap it may not have one so worth a check. It should be easy enough to drill one if it doesn't.

 

Cheers,

Steve

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Had a similar problem recently and after changing coil x 3, rotor arm, dizzy from electronic to old fashioned spare, cap and leads, all to no avail I decided to strip fuel system and found that rear HS6 float chamber valve was sticking, presumably due to a bit of crud.

 

Cleaned out whole system from pump. reassembled and hey presto - so far.

 

Chas

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Morning Mike,

Have you tried going back to points (eliminate any dodgy electronics).If I remember right,leaving the ignition on any length of time causes problems with Martins products

and he states this in the instructions.

Only a thought but you never know.

Regards Harry

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