Going mental

[New Bloke]

Now, I'm trying to follow advice and be methodical but I have limited time available so can only get out to do anything on it very infrequently. Today I took the top off of the float chamber and made sure the float moved freely, then I got my wife to switch on the ignition while I held the float up against the stop, no pump...."That's good" I thought, I released the float and allowed the valve to drop and the pump came on. So far, so good. I then used carb cleaner to give it all a good clean, then screwed the top back on. With the ignition on the pump came on and would not cut out even when fuel seeped through the lid. So I took off the lid and tried the whole assembly in a jam jar. As the float was lowered into the jar full of water, the float rose and the valve shut off. So more cleaner and back on. Same result. Could it be that the arm holding the float has bent, the float is oversized, the top is put on the wrong way? The fuel inlet pipe points towards the front of the car, is this correct? Still stumped. I've had a Triumph for nearly 40 years and never had half the trouble this thing is giving me.

[kennatt]

no its the needle assembly,the needle and or jet become worn and don't seal,enough to overcome the pressure from the pump,fit a new assembly and your problem will go away,

[New Bloke]

Thanks Kennatt,

http://www.morrisminorspareparts.co.uk/ ... r?start=20


This page shows the whole lid as one assembly, I guess I need to buy one of those......

[David W.]

You're looking for item 31, needle and seat. Possibly 27 and 28. The workshop manual shows just how to adjust the float level. I can't get to my copy to get a picture for you.
Here's a poor quality picture.

Carb Adjust Small.jpg (49.95 KiB) Viewed 3911 times

[New Bloke]

Thanks David and Kennatt, I'll give Charles Ware a shout tomorrow and try to get a needle.

[amgrave]

Just a thought but as the valve seems to work outside of the chamber and then does not when inside the chamber is it possible that the float arm is bent and the float is catching on the side of the chamber so stopping the valve seating on the top. The inlet pipe is facing the front on mine so it sounds like you have the top on the right way round.

[New Bloke]

I was wondering that Amgrave, for 7 quid to get a new needle, it's worth putting one in and seeing.

Cheers

[David W.]

It's "NEEDLE AND SEAT". I don't think you can get them separately, but change both.
As for the float and hinge pin, if yours is sloppy at all, go for a replacement. The float should move freely with no side to side movement.

[kennatt]

just change the needle and valve the only other thing to check is the float level AFTER you have changed the valve assembly,the only thing ever goes on the flaoat is that sometimes they spring a leak and let petrol in thus preventing it from floating up. It would be obvious there would be petrol inside it,the only thing you need is a long thin socket to get the valve out,it screws out of the body,

[moggiethouable]

Did the new distributor come with a new rotor arm?
Or cap?

[oliver90owner]

Did the new distributor come with a new rotor arm?
Or cap?

Very sorry, but totally irrelevant if a good ignition spark was available when the breakdowns occurred.

[New Bloke]

But thanks anyway, yes it came complete.
Update:

I changed the needle and seat, and the pump cut out, no seepage from the lid, so I took it round the block and in exactly the same place it cut out again. I have yet to rig up the lamp from the LT side as I don't have a 12v bulb and lampholder laying around, but I'm thinking of rigging up a wire and have my Son hold the voltmeter on it and shout out voltages to me.

[kennatt]

don't go out and buy test lamps or anything else just yet.
take it out and when it stops,before any component has chance to cool down ,take off the dist cap,pull the ht lead out of the top of the cap,the one that goes to the coil,the big thick one. with ignition on and holding the lead with insulated pliers close to the engine block flick the points open with a screw driver,if the coil is in good order you should see and hear a fat spark from the lead to block if not then the coil is suspect. Contrary to the popular"its never the coil"sometimes it IS.If you test it more then a couple of times the spark will get less each time as the coil discharges,so the first one is the test. if ok..........

Do it again and this time as suggested earlier take the top off the carb to see the petrol level.
I see you have a meter..to test the coil cold.....red lead to poss terminal black to neg terminal set meter to resistance/ohms should read at least 3 ohms, do it hot after breakdown instead of above (But good to practice above so you known what you should see and hear)

[David W.]

I would suggest as above, except, don't pull the cap off. Pull the center lead and hold it close to anything metal. Turn over the engine with the switch on. Too much opportunity to short out the points if you're operating them with a screwdriver. Of course, if you have the cap with the side entry HT leads, this won't work.
If you have the side entry cap, you could carry a length of HT lead. When it fails, remove the lead from the center of the coil, put your spare lead in, and see if it sparks to ground when cranking the engine.

[IslipMinor]

I took it round the block and in exactly the same place it cut out again

Did you do as suggested more than once and check if there is fuel in the float chamber when it cuts out? Make sure that you turn off the ignition before removing the top of the float chamber.

[kennatt]

you will not short out the points but if you are worried about it just use a plastic or wooden probe,its easier than trying to crank the engine ----two people,and by hand holding the lead and turning the bottom pulley or pushing in gear. if you have a push button solenoid,you could do it yourself under the bonnet if you are worried about the points.But you have more control by flicking the points because you know exactly when the spark should occur,so you can hold the lead close and be ready to watch for the spark,........Again CHECK THE CARB BOWL

[New Bloke]

Thanks everyone but I'm giving up. The problem is too much for me and as has been pointed out, I'm just throwing money at it now. I have engaged a mechanic to come around on Friday and sort it out. Thanks for all of your suggestions and as I hate leaving anyone up in the air, here is a summary of what I've found so far:

When it stops producing power, there is still 12 volts on the low tension side of the coil.
When it stops altogether there is still fuel in the float chamber.
When the engine stops, it will start again on the key but not produce power.
There is a healthy spark at all times (Except I can't see when the engine is running but not pulling as I am always inside it at that point).
The Fuel pump has now started running all the time again.

Thanks for all of your help and suggestions, I will make sure I report back after it has been fixed.

[oliver90owner]

Getting a proper mechanic, who knows the basics of these old engines, is probably your best move forward. A shame there has not been a moggie enthusiast near to you that could have helped sort out the problem.

The Fuel pump has now started running all the time again.

There are two usual scenarios with the above. Either it is not pumping fuel at all or it is pumping an excess. Very rarely would it be operating continously and only just providing sufficient fuel supply pressure. And very easy to check which of the two it is, but nevermind - I am sure a decent mechanic can sort it for you.

It is good thag you will come back and report his findings and cure - it may help others in a similar predicament.

[New Bloke]

Okay,

Hands up who said fuel? Go to the top of the class.

I had a new fuel pipe fitted by a garage a few weeks ago, they had miss fitted it and the end of the pipe was touching the bottom of the tank, every time I went up hill the fuel would stop going into the pipe, hence the pump working all of the time. By the time I got it back the float chamber had refilled it'self and therefore I didn't see it was empty. The mechanic took the sender unit out and moved the pipe away from the bottom of the tank and now it seems to be fine. My Daughter is not convinced and refuses to drive it so I hope to show her how good it is by driving her to her appointment tonight and picking her up.

Hopefully this is now resolved. I hereby give permission for all who said it was fuel to post "I told you so" messages.

Tim

[ManyMinors]

I'm even more confused now. I've never heard of anyone replacing the pipe INSIDE the tank. I'm not even sure it is possible? In any case, the pipe inside the tank surely HAS to reach the bottom otherwise how could the pump empty the tank on flat, level ground?
If the garage fitted a new main fuel line is it possible they didn't tighten it up fully? That might cause air to be drawn in and make the pump run continuously?