stange problem

[jake27081991]

hi all

yesterday i was driving and all was going fine... then i got to a round-about and decelerated going into it... when i went to accelerate to go through it, the engine died, not a complete stop but it sort of splutters as if you turn the key off for a second then back on again.... i then had to accelerate slowly to try and keep things going....

it was then fine again when i got out of the round about and back up to speed, then there was nothing i could do to get the same symptoms... i could accelerate fine and take my foot off the pedal and she just kept going....

then when i got the next round about... same thing happened again.. splutters a bit.. then keeps going..... once back up to speed... all is good again...

then when i got the next round about...... the car turned of completely... and wouldn't turn back on again.... after a few tries still nothing.... 5 minutes later and i could start it and luckily i could hobble home....but every time i slowed down the same problem would occur.... the car would turn off incrementally.... then just keep going...

whats going on??
some thoughts
-bad timing?
-something wrong with coil?
-some thing wrong with the condenser? (what exactly does the condenser do?)
- /i replaced the contacts a month or so ago... but all was working fine with the new ones...it defiantly breaks contact...
- with the leads have any thing to do with this? i didn't think it would be a problem because they still work at speed.

thanks in advance
Jake //58 van

[David53]

It sounds more likely to me that it's fuel related as opposed to electrical. How full was the tank? Just wondering if it was quite low and going round the roundabouts was causing fuel to slosh away from the pickup pipe?

[MarkyB]

Make sure the piston in the carb isn't sticking and drops with an audible clunk.
Too much air gives similar symptoms to not enough fuel

[bmcecosse]

Initially I would have said it was just 'surge' on the roundy - but then dying away completely does suggest fuel shortage. Check the pump output (pump a pint into a jar - tell us how long!) - check for vacuum in the tank. But also - try a new condenser - and check these points haven't closed up, or burned out. Failing condenser knocks hell out of points!

[jake27081991]

found the was a lot of contaminated fuel that i bought just prior to that drive.. after cleaning out the tank fully and cleaning out the whole system... the same problem is there... will start and idle fine but as soon as you try and put it in gear, and drive, it just coughs it self to death...

[bmcecosse]

So - it's not the 'contaminated' fuel then!

[MarkyB]

Contaminated with what?
Did you clean the pipe that goes to the main jet?

[bmcecosse]

Rev it up hard and stick your hand over the carb inlet (throttle still open) - that will suck away any 'contaminants' that are still hanging around.

[jake27081991]

it was contaminated with some horrible looking sludge, and even the fuel that was still in there wasn't to great looking.

whats the best way to see if the piston drops down easily? do i just take the suction chamber off and then lift and drop the piston? or can i just push the piston lifting pin and let it fall? then what do i do if it does not fall freely?

dont think ill be able to rev it up then stick my hand over the intake as i cant seem to get the stud that holds the air cleaner in out.. are there any tricks to this? i thought it would just be screwed in but i don't want to force it to much... it does wobble a little bit...

i am going to get new spark plugs just to make sure that its not them, as they may have been clogged up by all the bad fuel...

[David53]

I still think it sounds like fuel. When you accelerate it is not getting the petrol it needs. Does it only happen when you rev quickly? Are you able to gradually increase revs with a slow push of the accelerator and if so does it then hold high revs OK? If so, I would say is definitely a carb problem or a fuel supply issue. If it won't hold high revs or you can't increase the revs at all then possibly in the electrical system, my thoughts would be coil.

[charlie_morris_minor]

whats the best way to see if the piston drops down easily? do i just take the suction chamber off and then lift and drop the piston? or can i just push the piston lifting pin and let it fall? then what do i do if it does not fall freely?

The best way is to remove the air filter housing and then you can simply put your finger down the carb inlet and lift the piston and let it fall..

If it does not fall, check you have oil in the dash pot chamber.. if you have oil, the dash pot is held in by three screws undo take those out and you will probably find that both the chamber and piston are black.. get a little t cut and gently remove the deposit....

dont think ill be able to rev it up then stick my hand over the intake as i cant seem to get the stud that holds the air cleaner in out.. are there any tricks to this? i thought it would just be screwed in but i don't want to force it to much... it does wobble a little bit...

There is not trick to removing the air filter, my concern is you say it wobbles.. this is a difficult one to describe in writing but everything should be tight and it could be depending where the wobble is, that when you go around a roundabout something is opening up and disturbing the fuel / air mix which would cause your problem

[kennatt]

dont whatever you do clean the dashpot or piston with anything other than petrol anything abrasive will remove alloy and make the gap between the piston and dashpot larger the carb will be ruined very quickly if you do this.Try screwing the large nut under the carb right in then turn out 12 flats this is the basic mixture setting then play about with that setting screwing in and out to see if it then runs better good luck with it

[chickenjohn]

It does sound like a fuel problem, clean the fuel pump points and also the little filter in the fuel pump.

[mike.perry]

If the piston is not dropping properly try adjusting the tension on the three dashpot securing screws, if one is too tight then it can pull the dashpot out of alignment.
Check that the needle is not bent.

[adamroe]

I had something similar after I'd serviced Maureen, got about 10 miles from home and she started playing up. First thing I checked was that I had set my points correctly. A bit of roadside repair got me home but then started having problems again so stripped the distributor out, changed the condensor, reset the points, put a new coil and leads in etc but this still didn't resolve it fully so moved onto the fuel system. So I whipped the fuel pump out and cleaned out any corrosion and pitting, put it back in and away she went. Maybe worth a try.

[bmcecosse]

A wee rub with some T cut won't do the piston/bell any great harm - just don't do it every week! The piston must rise easily - and fall with a nice 'clunk' The air filter casing must come off! The front plate that holds the filter is surely held to the carb by two screws??

[jake27081991]

replace all filters, and checked the fuel flow, it is fine..

the problem is that when you accelerate, all is fine until you get to a certain RPM (on each gear) then it just splutters.. and losses all power until the next gear change (up) then it goes fine until it gets to a high RPM, this happens through all gears...

this same thing happened to me a while ago however it was much less restricting (as in it was just one stoke that didnt fire, not all of them) and all i had to do was pull the choke out and it would go fine again...

is there a way to check if the fuel bowl is stating at the correct volume??

and any other suggestion?

[charlie_morris_minor]

is it now happening in all gears at all times..

when you started the thread it seemed to be only when going around corners?

The normal problem in the float chamber is that they do not rise and therefore stop the petrol,
but if you remove the lid of the float chamber and turn it upside down, as i recall, you should be able to slip a pencil between the top of the float and the top of the float chamber.

earlier in the thread BMC suggested that you do a pump test have you performed this test yet?

[kittyfell]

Sounds like valve bounce to me..................