Morris Minor Owners Club

While driving along, the car started to surge or cut out at a point every second or so. After about 30 miles this got worse and I struggled to maontain speed. I began to wonder if I'd make it off the main road. I managed to get to a petrol station however couldn't reach 25mph once off the road. The engine appeared to idle fine.

Previously I noticed a rattling when the accelerator was midway down. I don't know if this is the same issue. In addition the additive bottle is running low so wonder if I used insufficient additive.

The car is being taken back as roadside couldn't identify the issue. How would I diagnose it?

Many thanks!

sounds like fuel starvation, ................low petrol level in carb ,faulty fuel pump , blocked vent on fuel cap (Take it off and see if it now drives ok):-? , Additive...take it you are using fuel additive, don't bother . not worth the trouble and it will not cause the symptoms you describe, Worth checking the oil level in the carb dash pot. And the jet setting on the carb(Ask if you don,t know or do a search )

Many thanks. The pump is working (based on clear inspection window in the tube) but may not be working to full efficiency. (The pump is relatively new mileage wider according to documentation).

Will try the rest cheers. The dash pot was filled with oil the day before the journey and I assume can't be overfilled (it would leak out right). Assume I should service the carb based on the manuakt for jet setting?)

If you a happy that the pump is working Ok,take the top off the carb(three screws) and have a look inside the fuel bowl,see if there's any crap inside and that the float level is high enough(Have a look in the manual for how to set,is see you have one),fiddle with the float which will cause the needle in the jet to be moved about,its possible that grit has got under the jet and is causing it to stick so not alowing full fuel supply on high demand,but enough to let it tick over,this will clear the jet.Then try it and see.I would leave the Main jet(under the carb ) alone at this point,they never clog up and don't suddenly cause faults,unless its been messed about from the normal running position.
However If you need to check,start the car and let it tick over to normal temp,then with your finger lift the small pin under the carb,untill you feel slight resistance,indicating that it has met the carb piston,then lift slighty again if the car instantly stops too weak screw jet DOWN slightly and try again,If speeds up and STAYS up too rich,screw Up and try again, You are looking for s slight increase in speed which then falls back and lets the car run but with a slightly uneven revs.
When you take the top of the fuel bowls off,the float will lift off with it be careful you don't loose the little pin that holds it onto the top cover.

The engine seemed to be running fine, but I suspect I'd have to drive a good number of miles to get issues again. I noticed the fibre washing is missing for the air silencer, which may not be in terms of dirt getting in. The dashpot pluger is loose from its cap (is this a problem?). There is also no seal between the lid and the float chamber.

The float chamber has some red grime at the bottom. Float level seems reasonable (petrol close to the top). I cannot find the pistol lifting pin (nothing is sticking out where it's meant to be according to the diagrams).

Should I remove the float chamber from the car and take it indoors and clean with washing up liquid? Can I simply pour the fuel back into the tank?

I think I'll order a carb kit to replace all these parts as a precaution.

What do I do about the lack of the lifting pin? Is it stuck inside?

Don't start on the carb! There's nothing wrong with it... Sounds like condenser problem to me.... Did you look at the points gap?? Another situation where a brand new Simonbbc or Accuspark dizzy would solve an awful lot of problems..... 45 D is best and electronic if you can afford it....

Thanks. What's the diagnosis to confirm this? The points gap being incorrect would cause it to work fine until it's been going a while? The coil looks like it's from the 80s. Should I just get http://www.simonbbc.com/electronic-igni ... any-morris or should I replace the dizzy/coil at the same time?

I wouldn't change the coil.....oldies are the BEST !! But do check for loose connections. That' s just a kit to fit to your dizzy (and do you have a 45D ??) - if it has wear/problems/failed vac advance.....then they will still be there.. get a complete new 45D electronic dizzy.... You won't regret it.

Sorry turns out the points, condenser and spark plugs were replaced a year and a half ago, so about 600 miles ago. Distributor cap and rotor arm 6 years ago or 1.500 miles. I will check the gap tomorrow in case that has changed. Tempted to go for the £50 upgrade for reliability, but it can wait if the current system isn't knackered.

So these replaced points/condenser etc are highly suspect.... hopefully the plugs will be ok - what make are they? Not NGK ?????

Plugs are champion.

It seemed hard to tell due to the assembly, but I think the points were only about 0.010" apart. I've adjusted them such that the 0.015" will move along but be tight but the 0.014" will fit easily. 0.015 is the highest I have, I should have got a bigger range so I could try 0.016".

Many thanks. Anything else I can do for diagnostics except going on a long journey again? Went up a long steep hill earlier but no issues.

Today I drove it a fair distance. The engine did seem a bit weak at times, but not enough to be sure it wasn't just gradients.

However, when I arrive back, I decided to inspect the float chamber. The petrol was about an inch from the top. I turned on the ignition. and the pump worked about about a minute to fill it up. The pump had a good voltage over it (13.6V). The continuity test suggested a good connection from the earth wire to the negative battery, but was intermittent for the positive side of the pump (normal because of the length of wiring, or rewiring job?). The pump is from 2013. Should the pump be able to keep up more than this?

This gauze is fitted. When I stopped, the gauze had about half cm of fuel at the bottom, but after about a minute of pumping, it was as it is in the picture.

Does this mean that the pump, for whatever reason, isn't keeping up with the needle?[frame][/frame]

if that is an external filter ,Take it off, causes more trouble then enough,there is an adequet filter in the pump<See manual re cleaning) To test pump , flow rate, should pump 1pint per min,give or take a couple of seconds or so. Just take off from Carb(After you have removed that filter and replaced the tubing with proper petrol hose) put it into a container,with a pint mark and switch on,and time it.

Fuel pump is delivering the correct output. The pump made a clicking sound, which I assume is correct operation?

What's the "proper petrol hose"? I assume the hose at the bottom pre-dates the addition of the filter. The filter was installed to check to see if the car had run out of fuel by the previous owner (cannot trust fuel gauge).

So either a float/needle problem, or the float level is usually a little lower when running than if the car has been idling?

How do you know - did you time it over a couple of pints ? I doubt it's a fuel problem - but certainly get rid of that filter........ Have you changed the condenser yet??

Timed 15 seconds since I don't have a large enough container handy, and works out close to a pint a minute with the up-scaling. I can buy a large cheap measuring cylinder for a repeat test.

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?)

Is it normal for the car to still be pumping fuel for a minute once parked or should the float chamber/pump be keeping up within a few seconds?

"proper petrol hose " ?
The existing petrol pipe will have been cut, to insert the clear glass fuel filter.

kennatt's comment relates to the replacement being : - 1.the right length ( enough to allow slight engine movement, without straining the flexible pipe )
2. made of the right material , that is ,suitable for unleaded petrol, which is harsh on ordinary rubber ( and would soon lead to deterioration of the pipe...then a leak of petrol... then a fire / boom !! )
Whether you go for a plain rubber or reinforced fuel pipe ( like the existing pipe on your vehicle ) replacement is up to you.
Bob

Many thanks! It's possible that it wasn't as the external filter is routed to the right of the wiper motor (or would be left to droop which may not be ideal) and I think the newer tube (from the pump to the in-line filter) may be long enough to reach the carb but will check.

Sounds like a good idea to replace the whole thing though! What's the point of the metal protection if the hose is the correct length? Stray sparks?