Carb

[Philbrooks]

Hi All

I have a Minor 1000 1967.
Was running ok, but was given a shiny new carb, that i wanted to fit.
I removed the old one and noted everything that I need to note before taking it off.

I have put the new one one and put everything back in the same way as the old one was set up.

For some reason the car wont start now. There is fuel going into the float chamber, the fuel pump is working, however, it just wont start. I sprayed some 'engine start' into the carb but it no joy.

I had put the accelerator cable on a bit too tight, but fixed that.
What do i need to check to get it going again? As soon as it starts i can then adjust the idle and the mix.

Cheers

[bmcecosse]

First off - is it an identical carb ? Is there a tapered needle in the carb? And does the piston rise and fall easily with finger pressure? Any chance you may have disturbed a wire to the ignition when working with the carb? It's surprising it didn't run for a few seconds when you sprayed in to the carb - that would suggest an ignition problem.

[Philbrooks]

Hi. Thanks for reply.

Its an identical carb, just has a stainless dashpot and chamber as well as being really clean!
when i try and turn the engine over it just makes that trying to turn over noise!

I will check the ignition tomorrow, though and update post.
I think it has a tapered needle, I might try the needle from the original carb.

the piston rises and drops nicely as it should.
Cheers

[amgrave]

Try half an egg cupful of fuel down the carb throat before turning the key, if it runs for a few seconds the problem is the new carb.

[Philbrooks]

Thanks for your guidance guys.

I have slung petrol down the throat of the carb, but still not starting. So am i right to assume its a spark / ignition issue? It makes all the noises as if its going to start but never quite makes the leap!!

I am going to go and check the other side of the engine now.

Quick Question, what is the best way to check the spark? I did see my mechanic do it once with a screwdriver on an old triumph herald i had. I just though i should test everything before i go and get new cap, leads and plugs (although will probably do that anyways!

Cheers

[myoldjalopy]

It 'shouldn't' be an ignition issue if all you did was swap the carb, but its possible.
Check the choke cable is properly connected and working as well as the accelerator cable.

Best way to test for a spark is unplug the king lead from the dizzy, hold it about 1/4 inch away from the engine block and crank the engine. There should be a spark as the points open and close. If there IS a spark, replace the king lead in the dizzy and then see if the plugs also spark in a similar manner.
Depending on results, the fault may lie in the low tension circuit, or in the dizzy cap/rotor/plug leads/plugs.
See what happens and that will narrow down the problem........best to test systematically before replacing lots of ignition parts - its almost certainly going to be one single (and probably simple) thing.

[Philbrooks]

myoldjalopy thanks for your reply.

I have checked the connections to the Accelerator and Choke and seems to be all fine.
I will go out (when it stops raining) and have another look.

thanks for the tips on checking the spark. I will do this after checking the accelerator and choke.

Once again, thanks for speedy response.
Cheers

[panky]

Remember to hold the king lead with insulated pliers or you will get a shock

[Philbrooks]

Remember to hold the king lead with insulated pliers or you will get a shock

Thanks for the advice!! might have ended up in next doors yard!!
Cheers

[bmcecosse]

The most likely thing is that you have somehow disturbed a connection when fitting the carb. Highly unlikely the engine suddenly chose that moment to fail the ignition all by itself!

[crackers]

Been two days. Still looking for the problem or have you found it and are too embarrassed to admit it?

Low tension lead to the dizzy is a popular one to knock off, especially if it's a loose fit which I've found a few times. Of course, you might just be using the wrong swear words.

[bmcecosse]

Simply refit the old carb - only takes minutes - no need to connect everything for a test - does it run now?

[Philbrooks]

Thanks everyone for your messages.

So, checked the Leads and there was a spark form the coil, so, seemingly it was just a bit loose and not producing a spark to the cap.

Managed to get it running YAY.
However, sounded awful, presumed it was the mix settings but wanted to take it for a bit of a run first, to get the engine warm.

Left it ticking over for a while, but after about 5 minutes, it just cut out and wont start again!!

Quick additional question! When refitting the carb, what sealer would you recommend? It has got the paper gaskets on, but someone said that it would probably need to be resealed to prevent loss of pressure or air leaking. !!

[bmcecosse]

NO sealer at all! BMC didn't use sealer -why would you now? Does the new carb (and i've never heard of one with a 'chrome' bell - sure it's not just a thin sleeve....?) have a large breather in the side to be connected to the rocker cover? If so - block it for now. I still say - pop the old carb back on (5 minutes - no need for cables - just the fuel pipe) and see if that still works. Can we see a picture of what you have fitted? Is the float bowl at the correct angle??

[SteveClem]

Take it to the oldest back street mechanic that you can find. Usually they solve it in half an hour and then spend another hour telling you their life story. It's great!

[Philbrooks]

No breather on the carb, oew and old.

I have a mobile mechanic coming over on Thursday to take a look and see what he can do, He has been in the industry for over 25 years, so he might know what to do and, give me his life story to boot.

I will let you know how it goes.
Thanks again to everyone

Cheers

[bmcecosse]

Oh well - I just don't understand why you won't take the 5 minutes to swap the old carb on and try that again !

[The vast minority]

Talk of sealer and no breathers....don't worry, you have to learn but as others have said, never use any sealant and you should have a breather. A minor is amongst the simplest of cars to work on so if you are struggling then it will be wise to get help whilst your knowledge grows.


are you confident in the installation? did you clean up the mating faces properly and put a new gasket in place and make sure the joint was made securely? If not, you will be drawing large amounts of air into the inlet and this will make the mixture too lean to run. Even with petrol and magic starting fluid, if there is too much air then it won't go. Petrol is sucked into an engine-from the carb by vacuum created by the piston on the induction cycle moving down the cylinder. An air leak between carb and manifold not only allows air in, it prevents enough fuel getting in by virtue of the reduction in vacuum Have you got proper imperial sockets and spanners?

Whatch what the geezer does, he will probably check for petrol first, then check for spark, after this he will start to look for the problem which I suspect is one of induction.
Good luck and please let us know the outcome

Al

[Philbrooks]

Good Morning All

Thank you all so much for your advice and guidance.

bmcecosse i did as you suggested and put the old carb back on, no joy.....
So: i put the new one back on with the needle from the old one!
then i changed the leads, simple because the Coil, Plugs, cap and Arm had all been replaced so i thought what the hell!

Turned the key and boom, started straight away!!
No idea what it was but i was really chuffed it started!

Just needed a bit of adjustment as it was idling really fast and the mix screw was all the way to the top.

So pleased it burst into life!!

Thank you all once again.

[bmcecosse]

You didn't tell us before that you had changed anything else...... So refitting the old carb proved that the new carb wasn't the problem, and so lead you to the real problem. Well done - so the 'golden rule' is that you should only change ONE thing at a time - check it's working, and only then change the next thing.