stuttering over 40mph

[MoggyBlue]

Hey guys
So I seem to have a problem with Ona
She starts fine, idles fine, drives fine ( well up until 40 mph)

So when traveling 40 mph or 50mph she starts stuttering (but doesn't cut out) if you put your foot down more whilst the problem is happening nothing happens. If you take your foot off the pedal and back on hard it most of the time stops the problem.

I've done a few things and seems to have In proved it to the point that I can do 50 and over happily for an extra few miles then the problem will arise again.

I've replaced
Plugs
Leads
Cap
Points
Condenser( distributor doctor)
Checked tappets
Checked carburettor (piston was sticking but seems to no longer be)

I have just tested my fuel pump (originally had an SU pump on but had to do a little repair on it so removed it and put my other moggies hardi fuel pump on whilst it's being repaired just to say it did feel down on power as soon as the pump was fitted but may have just been me) I've tested the output and is kicking out between 700 to 800 ml in 1 minute I know it's ment to be 1L but is this acceptable?

Any ideas where to go to next will double check mixture is where it should be this weekend but wouldn't have thought that would make it intermittent though
Any ideas much appreciated
Thanks and almost going to loose it with this traveller

[dalebrignall]

is the timing out of kilter , air filter clean, is the carb clean inside might be worth spraying some carb cleaner down it , connections to the coil good and tight , and is the lead from the condenser not pinched up .

[MoggyBlue]

Hey thanks for the reply
Timing has recently been done. Was originally way out now is at where it should be according to the manual
Air filter is clean
May have to give the carb a blast with some cleaner
Thanks for the suggestions will have a go and check it all this weekend

[panky]

It does sound like the fuel pump is struggling to keep up, was it OK when the original was on? Maybe a little bit of crud in the float valve restricting the flow.

[bmcecosse]

The delivery from the pump sounds fine. Try briefly without the air filter fitted. I would go back to the carb since you thought the piston was sticking and check again - and try some heavier oil in the little damper. You can't rely on the 'manual' for timing these days - first check the vacuum advance is working (suck the pipe and watch the baseplate move) and then twiddle the dizzy for best idle - follow up with a check that it is NOT pinking when accelerating hard. In the dizzy - check the little 'no volts' wire is not frayed/broken - and clean/check the coil connections. Also - is the coil connected right way round for the car's earthing? Assuming -ve earth - then the SW (or -ve) connection should be running to the dizzy - white wire with black stripe.

[MoggyBlue]

It does sound like the fuel pump is struggling to keep up, was it OK when the original was on? Maybe a little bit of crud in the float valve restricting the flow.

I did wonder that and yes I could happily get up to 70 no issues but that was a while ago now and had.many jobs done since then. Now she's a bit sluggish to get up to speed and can get to 60 eventually at a push engine noise does seem a bit higher to at the moment

[amgrave]

Check the counter weights are not sticking under the distributor base plate, hold the rotor arm and see if it moves easily without binding.

[MoggyBlue]

The delivery from the pump sounds fine. Try briefly without the air filter fitted. I would go back to the carb since you thought the piston was sticking and check again - and try some heavier oil in the little damper. You can't rely on the 'manual' for timing these days - first check the vacuum advance is working (suck the pipe and watch the baseplate move) and then twiddle the dizzy for best idle - follow up with a check that it is NOT pinking when accelerating hard. In the dizzy - check the little 'no volts' wire is not frayed/broken - and clean/check the coil connections. Also - is the coil connected right way round for the car's earthing? Assuming -ve earth - then the SW (or -ve) connection should be running to the dizzy - white wire with black stripe.

Hey bmc wondered how long you'd take ;)
Hmm ok well ill keep looking then
I'll be doing about a 10 mile drive so will remove the air filter before I go but will leave the housing on.
Oh ok I put engine oil in any way though is it worth trying other grades?
Hmm now you mention it I'm getting a knocking recently on hard acceleration or when under strain once things smooths out it stops. Honestly never head what pinking should sound like so can't really say it is that or not but it just feels like it's coming from back of engine area
No fraying on the wire and vacuum advance works but will test again on the weekend
Coil should be connected properly but will clean connections. There is a a dent in the coil housing this wouldn't affect anything would it?

[MoggyBlue]

Check the counter weights are not sticking under the distributor base plate, hold the rotor arm and see if it moves easily without binding.

Ok thanks I'll give it a go

[amgrave]

Knocking on hard acceleration does not sound good. Is the engine oil topped up OK and with the correct grade.

[MoggyBlue]

Knocking on hard acceleration does not sound good. Is the engine oil topped up OK and with the correct grade.

Yeah oil topped up its only when you really give it some or try get it up a hill at low speeds. To be honest I wouldn't really call it knocking like a conrod or anything may be timing would make sence and think it only started once timing was done

[Trickydicky]

Knocking on hard acceleration does not sound good. Is the engine oil topped up OK and with the correct grade.

Yeah oil topped up its only when you really give it some or try get it up a hill at low speeds. To be honest I wouldn't really call it knocking like a conrod or anything may be timing would make sence and think it only started once timing was done

Sounds like you have found the issue if it only started after you adjusted the timing

[MoggyBlue]

Knocking on hard acceleration does not sound good. Is the engine oil topped up OK and with the correct grade.

Yeah oil topped up its only when you really give it some or try get it up a hill at low speeds. To be honest I wouldn't really call it knocking like a conrod or anything may be timing would make sence and think it only started once timing was done

Sounds like you have found the issue if it only started after you adjusted the timing

Hopefully it is just that will report back when fiddled a bit and driven it pinking never even came to mind to be honest would thst cause my issue though? Being fine up until 40 mph and not doing it every time now?

[bmcecosse]

Pinking is just more of a 'rattling' sound - unless it has gone even further and is actually 'detonating' - which could sound like a 'knock' and is very destructive to the engine..... What can happen is that the vac advance fails - so the engine doesn't idle too well (when there would normally be a bit of vac advance) - the owner then advances the ignition setting to get a good idle -and then it's too far advanced when running at revs. So as others have suggested - back off the timing, don't let it 'knock' - and check that vacuum advance. If it has failed - I suggest perhaps a complete new 45D dizzy from Accuspark/Powerspark (electronic if you wish) will save you having any more dizzy worries for a few years !

[MoggyBlue]

No no it is quite a rattley noise fingers crossed that's it then.
Ok I ended up having to sort my friends brakes out so never got to play with the traveller will have a go today and hopefully fix it. It already idles quite well though but will see what happens
I have been thinking about a dizzy upgrade as my saloon has an electronic ignition 45d but the funds just arnt here right now

[bmcecosse]

Well -check that vacuum unit, and take the timing back - it must not be allowed to 'pink' which is what your rattling probably is. I know what you mean about 'funds'... but the non electronic is not bad at £40 and the electronic version not that much more at £60. I would NOT advise a 'conversion kit' for your own dizzy - you want a complete new unit, but carry your old dizzy as a spare - to help out others stuck at the side of the road!
http://www.ebay.co.uk/itm/Mini-AccuSpar ... EU0zBQjuUQ
http://www.ebay.co.uk/itm/For-Morris-Mi ... D0uf_Sb2BQ

[oliver90owner]

If you are trying to accelerate hard, there will be little or no vacuum advance. Seems like over-advanced. You could try using the super unleaded fuel of higher octane rating to see if the problem is reduced or even cured? My money is on timing, or maybe an awful lot of coke in the engine!

RAB

[MoggyBlue]

Hey guys quick update. I've played with the timing and thought I'd better check my vacuum advance again and GUESS WHAT try suck on the pipe and nothing happens (copper piping) moved the pipe just a little bit and it's fractured and snapped off now. So used a plastic vacuum pipe I have on my saloon and looks like my bade plate is not moving at all

[bmcecosse]

So there's the problem -a new vacuum unit is almost as much as a new dizzy - so I know what I would do..... The vac units last about 20/30 years.....not bad going really.

[MoggyBlue]

I don't want to jinks anything but fitted my saloons old working 25d and backed the timing off a bit. been for a drive round town and accelerates better, is quiter and weirdly even the clutch feels better will find out if it can handle hills and high speed on Tuesday but fingers crossed it's fixed it p.s no rattley knocks it seems thanks for the help guys and Roy, once the nationals is over and I've got and bit more in the bank I may look into a new dizzy also will look into a hs4 carb possibly but Shhh