Loss of power / surging?

[bmcecosse]

There should be no pumping once the engine stops -maybe one click....... The float valve may be leaking. Your pump is fine - don't bother with any more tests! I would change the condenser - for a 'good' old one. Also have a good look at the rotor arm.

[mogbob]

If the carburettor is missing it's gasket, between the fuel bowl and the lid, then getting the fuel float level correct is going to be a bit hit and miss.If you've come to a screeching halt and leave the engine on tickover then a full minute with the pump stil trying to pump seems a long time.Check the float level ,once the overhaul is complete or the float bowl gasket has been fitted.When overhauling ,check that the float itself doesn't have a small hole in it, allowing petrol to get in and float to "sink" further than it should.
If the points are pitted after 1,500 miles then expecting another 2,500 miles out of the points ( without at least having cleaned them ) is a big ask ! The slight " bump " is indicative of a suspect condenser.If you don't replace it, even after a clean up of the points, it will pit again very quickly !!

DO AS bmcecosse SUGGESTED REPLACE THE CONDENSER ! A new set of points would set you up with a running spare distributor. Replace the whole distributor later as you wish.

You have a number of minor niggles with the car.In combination they defeat your attempt to achieve carefree motoring.Each element is not a major issue but " half correcting " each one, still leaves you with a problem.
The correct parts , properly installed and tuned will pay dividends.
Bob

[Trickydicky]

I didn't change the condenser, but have re-gapped the points (which had a slight bump). I'd rather do another 2,500 miles then replace the whole distributor rather than replace the points/condenser. (Unless, I should replace it now and keep the current one in the boot as a spare get home one?)

A failing condenser will cause points to pit, as will if the points are incorrectly gapped.

Here is a great source of info ignition related, well worth reading. http://mgaguru.com/mgtech/ignition/ignition.htm

While I agree that electronic ignition will cure any problems created by faulty points and condensers, decent quality ignition parts are available, they just cast a little more.
Most people when servicing the cars replace ignition parts when they are not faulty, creating problems with faulty replacement parts. I suppose what I am trying to say is, If it ain't broke don't fix it!

[nwxh]

The points have only been 600 miles and have a small bump. So if that's a sign of premature failure, I will get a whole new distributor with electric ignition and save the current as a backup. I checked and the current is a 25D, so I assume I'll get a new 25D? I'll get a carb service kit too. Many thanks!

A failing condenser will cause points to pit, as will if the points are incorrectly gapped.

I'm guessing it was the latter then.

[bmcecosse]

The 45D is a better dizzy..... I don't think you need a carb service kit..but it's your cash!

[nwxh]

The 45D is a better dizzy..... I don't think you need a carb service kit..but it's your cash!

Thanks, I've seen an earlier post by you in 2012 indicating why it's better and cheaper.

You think the float not keeping topped up issue is simply because of the extra in-line filter or a leak? I should definitely replace the missing gasket and seal. What is the float valve spoken of? Is it between the float chamber and the carb or referring to the float and needle assembly? Should I replace the whole float chamber gap with the new piping?

[bmcecosse]

The needle valve is in the float chamber lid. It develops a ridge on the taper and starts to allow fuel to dribble past - even when the float is up. This doesn't matter when running - the fuel is being used - but when idling (and when the engine stops but pump is still energised) then fuel can continue to leak past and will simply 'well over' into the inlet manifold -and makes hot starting difficult ! So a new float valve won't go wrong unless you know yours has been renewed in living memory.....

[nwxh]

Thanks for the help. Sorry I'm a little slow

So if I understand correct you believe a) there is no fuel starvation issue b) the main carb assembly is fine and shouldn't be touched for now c) the fuel pump might be continue to operate once stopped because the float needle is worn?

So I should/might as well buy:
a) New 45D distributor with electric ignition so all ignition problems go away
b) New fuel hose unleaded friendly
c) New float chamber lid assembly plus gasket. (or just the float, needle and seat?)

[Trickydicky]

If the float/needle valve is not shutting off the fuel supply to the carb there will be fuel seeping out of the top of the float chamber where the petrol pipe attaches, this is usually an indication that either the float is punctured and is too heavy to close the needle valve or as Roy says the needle valve is worn, is yours doing this?
If you have no float lid gasket then replace it, I would also order the three screws too as the heads get chewed up over time.
Buy a new petrol feed pipe and ditch any in line filters.
Regarding the new dizzy, I would just put your "old" condensor back in and see how it performs first then make a descion on spending money on a replacement, but it's your choice.

[kennatt]

It's got to the stage where you are going round in circles and getting no where fast. Before you do anything else.
No1 Change the condenser and drive the car if no improvement
no2 Take the external filter off and fit the pipe straight to the carb.....................then drive the car if no improvement.(Take it off anyway it's doing nothing at all )
No 3 Do you know how to ,or are are you confident enough to check the ignition timing ,do a search ,BMCs way (The pinking test) is the easist and best. Be aware that altering the points gap also slightly alters the basic timing,the rattling you mention on first post,could be Pinking caused by over advanced engine timing.

BUT, what car is it ,engine size,how many miles,are you familiar with old cars and their performance in relation to a modern .ie you're not expecting too much from a small high milage 850cc if you see what I mean. It would be very useful to know what the cylinder compressions are which would give us an indication of the general state of the engine (Any reasonable garage would be able to do this for you)

Just don't go out spending money on things that are working perfectly OK. A mistake Many make is to change various units and then never find out what was causing the fault in the first place. Or worse ,still have the fault due to basic engine adjustment.

Where abouts are you someone near may be able to assist,there's usually assistance at hand from another member.

[bmcecosse]

Great advice there . Treat yourself to one of these http://www.ebay.co.uk/itm/AUTOMOTIVE-PE ... 51b3a32b06

[nwxh]

Thanks again. I am definitely going in circles, and I guess there's a difference between diagnosing the issue and upgrading what ought to be upgraded.

No1 Change the condenser and drive the car if no improvement

Will try this first, new condenser and points ordered.

No 3 Do you know how to ,or are are you confident enough to check the ignition timing ,do a search ,BMCs way (The pinking test) is the easist and best. Be aware that altering the points gap also slightly alters the basic timing,the rattling you mention on first post,could be Pinking caused by over advanced engine timing.

I could believe this. It's not doing it while idling, so I assume I just adjust the micrometre knob five turns clockwise and then drive it and see if anything changes?

BUT, what car is it ,engine size,how many miles,are you familiar with old cars and their performance in relation to a modern .ie you're not expecting too much from a small high milage 850cc if you see what I mean. It would be very useful to know what the cylinder compressions are which would give us an indication of the general state of the engine (Any reasonable garage would be able to do this for you)

Morris Minor Traveller 1968, 1098cc, silver seal engine fitted in 1985 on 12,500 miles. It's now on 86,000 miles.

No experience with older cars. This is the first car I've ever owned. Before that, the oldest I drove was 2000. But I'm not expecting any performance per say, just consistency.

Location is Bath.

Great advice there . Treat yourself to one of these http://www.ebay.co.uk/itm/AUTOMOTIVE-PE ... 51b3a32b06

Ordered, was planning on getting one once the other things were sorted. Surprised at the low price, but as long as it gives a good measurement.

[Trickydicky]

Don't buy one of the cheap condensors, buy one of these,
http://morrisminorspares.co.uk/shop/pro ... 9710dba6cd

[nwxh]

Ooops, I ordered a traditional points/condensers/rotor arm set from Accuspark at the same time as getting a new 45D electric ignition distributor. The idea is to the keep the former as a backup.

Is the default Accuspark clever enough to adjust timing itself based on a look up table (once the static advance is set at idle by the "advance until pinking stops", or would you have to still have to get a nice idle, then make adjustments after driving)? Also is it normal to get intermittent sounds when engine breaking, e.g. on a long downhill?

[bmcecosse]

It just comes with a standard advance curve - probably not perfect, but then neither is the one in your old dizzy. Just get it started and warmed up thoroughly - then twiddle it back and forth and settle for smoothest idle. Then road test it - and if 'pinking' you will need to retard slightly. It MUST NOT be allowed to pink when running. Let us know how you get on with the new 45D. I assume your car is already -ve earth ?

[nwxh]

It just comes with a standard advance curve - probably not perfect, but then neither is the one in your old dizzy. Just get it started and warmed up thoroughly - then twiddle it back and forth and settle for smoothest idle. Then road test it - and if 'pinking' you will need to retard slightly. It MUST NOT be allowed to pink when running. Let us know how you get on with the new 45D. I assume your car is already -ve earth ?

Already negative earth. I should go straight for the new dizzy rather than testing the current with new points/con for a few hundred miles?

[bmcecosse]

New dizzy - get in there!!

[nwxh]

Thanks again for all the help!

45D dizzy is installed. Took a few hours partially because I was unfamiliar with the process, but mainly because it seems incredibly difficult to access some of the nuts, sometimes moving half a flat at a time. (I should get a flexible extension bar). I wondered about the coil for a second, only to realise it was still connected for positive earth!

Car is driving. I'm still trying to get the mixture right prior to dizzy adjustment. As I was using a colour tune, the engine cut out after weakening it to flashing between orange and blue. I stopped adjusting it thinking the battery might be getting flat as I noticed it wasn't charging (i.e. ignition light remaining on). Unfortunately my HS2 carb doesn't seem to have a lifting pin, so I'll have to try this more tomorrow.

I'm finding it hard to discern between pinking and normal juddering. But I think I managed to get it not pinking while driving after some adjustment. I will try and get the mixture right tomorrow and then left the dizzy slightly lose for adjustment on hills over the week.

[bmcecosse]

Put the colour tune away..... All HS2 had a lifting pin - sure it's not stuck UP?? Could be holding the piston off the bridge. If it really doesn't have one - just use a thin screwdriver blade to lift the piston slightly to test for mixture. No point going on if not charging the battery .....fix that first.

[nwxh]

I gave up searching for the lifting pin when I was told not all HS2 had it. But if they do all have it, I suspect it is stuck up. Would I have to take out the carb to release it? Cheers!

The charging is fine normally, it just wasn't charging while I only had three cylinders working due to the colour tune.