Won't start

[markthe45king]

For a few days, Lily struggled to start - lots of whirring and then only firing eventually. I assumed this must be the starter motor, however she also had a tendency to cut out a few hundred yards down the road before starting again. I've recently replaced the battery, and generally she was running ok.

A couple of days ago she packed in altogether and refused to start. The fuel pump was getting power but didn't appear to be pumping, so I thought that was my easy win. Apparently not, the replacement pump was as bad. Put the old pump back on and removed the fuel pipes in and out and the pump was pumping, but not really clicking. checked the pipes - there's an inline filter - and filter by disconnecting and reconnecting the pipes bit by bit, so i know there is petrol getting as far as the chamber.

We did the filter off, hand over the inlet to suck the dirt out thing and after a recharge of the battery and a full out choke she started and ran ok on the drive.

Took her out and she was sluggish pulling away and managed 50 - 60 in about 5 minutes and she's normally quite nippy. Then after leaving her overnight we are back to the original not starting scenario. So what do people think?

I've replaced all the fuses, and will try and do a compression test tomorrow - which i will have to watch youtube videos to work out how to do. So if the MM gods are smiling on me and the pressures are fine, what's next? I'll blow air through the pipes, but is there an easy way to clear the chamber apart from the hand over the inlet or will i just be taking it apart? And if none of that works, what next? Basically, what would be the best way to work through the process?

Thanks as ever

[simmitc]

The one thing that it won't be is the fuses, so forget them. There are many threads that will cover the fault finding process; but basically it's going to be a question of working through the things that should get serviced.

It sounds as though you have eliminated the fuel pump as a cause of the problem, but get rid if that inline filter, they are unnecessary and known to be problematic. You can do a flow test of the pump into a measuring jug. As long as it manages two pints in a minute then it will be fine. The float chamber doesn't usually get that dirty, but the lid can be removed without dismantling the rest of the carb.

A compression test is simple if you have the gauge: Gearbox in neutral, handbrake on, remove all spark plugs. Depending on fitting, either sacrew gauge into number 1 plug hole or hold it firmly against the opening, and spin engine on starter. Note reading. Repeat for all four cylinders. You can do this "dry" and then repeat after squirting a small amount of oil into the plug holes to get a "wet" reading.

However, I would start by cleaning and gapping the points and checking the timing. Alos look at changing the rotor arm and distributer cap - do only only thing at a time so that you know what the problem was, and keep the originals in case there is nothing wrong with them.

Check that the choke is operating correctly. Check that the air filter is clean.

Good luck, a propely serviced Minor will always perform well, so it's worth spending a bit of time getting it right.

[andypocock]

I'd start with the basics, plugs, points, condenser, good battery terminal contacts. As mentioned make sure the choke is operating correctly.

If she was running fine and then just started to struggle to start it's not likely to be compression related. Not to say that the compressions might not great but she was running like that before.

Andy

[oliver90owner]

All an engine needs (to run) is air, fuel, compression and a spark. Of course the air and fuel need to be in a corrct ratio range and the spark must occur at the correct time and be above a cerain minimum standard.

Seems this engine is in need of a proper service tune up. There are several minor points which can prevent satisfactory running, either together (cumulative) or individually. If everything is set to the 'standard' specification, the engine should run when cranked over at a quite slow speed (think here handDon starting).

Don't assume anything - check out each system and ensure that each is within specification, as given in the common service manuals. Engines like these (older designs and manufacture) require regular maintenance to keep them in tip top running order.

I'm sure Lily would appreciate some tlc on a regular basis. This would avoid most breakdowns due to a proactive approach rather than an after-failure panic.

[kennatt]

The clue(maybe) is when you placed your hand over the carb inlet,and it started afterwards. You have basically used a choke,inducing a more rich mixture into the carb. The su carb never suffers from a jet blockage because of the design ,the needle is constantly being drawn up out of the jet with the demand of the engine so always clears any dirt that enters the jet. However the jet /valve in the float chamber is an well known trouble spot because it does clog up/wear..................Switch on and let the pump work for a few seconds,switch off and take the top off the float chamber.three screws on top .the bowl should be full of petrol. If not you need to clear the valve,its where the arm from the float fits to the side of the carb,just push the float up and down.If so its probable that you will need a replacement valve and needle ,obtainable from most suppliers .With the top off switch on and see if the pump now fills the bowl and STOPS when full,just hold the top of the float to stop it overflowing. If all is well in the bowl,get someone to pull the choke and watch the bottom of the carb to see if the mechanism under the carb moves downwards,if not then the choke needs adjusting. If all is well,at the base of the carb, just above the choke/jet assembly ,you will see a large nut.screw this nut right up into the carb (With Fingers its not tight) until it stops,then unscrew downwards counting 12 flats. This is the basic setting which may require tweaking up or down for optimum performance. Try the above before changing anything else and report back....... Thinking about it do the choke test and 12 flats first brain and fingers out of sync haven't been up very long good luck

[markthe45king]

I think the TLC response may sum it up - lots of little faults mean I'm buying new gaskets for the carb, a new dizzy cap some new leads and plugs and a new air filter, and then trying again!

The inline filter was put in to deal with a fuel evaporation issue, but i will replace that too.

The chamber was refilling ok, but had a lot of crud in, so the carb is off now and won't be going back on until the gaskets have arrived and then I will update

[liammonty]

Agreed re the TLC approach - give it a good service. I'd put money on it being an ignition fault rather than fuel. Don't forget to check and gap the points - points closing up (which happens as they wear) could well have caused the symptoms you describe. I'd suggest replacing items one by one - that way you will have a chance of identifying what the problem was. Also, hang on to the old ignition components in case any of the new ones are faulty. I'd recommend the 'Distributor Doctor' as a source of reliable ignition components.

[markthe45king]

So i did a compression test - admittedly on a cold engine - but there's something wrong - front to back we got 155 125 125 155, did them twice and got the same again.

So now I'm assuming lots of work?

[Trickydicky]

So i did a compression test - admittedly on a cold engine - but there's something wrong - front to back we got <a href="tel:155 125 125 155">155 125 125 155</a>, did them twice and got the same again.

So now I'm assuming lots of work?

You could have a failed head gasket there.

[liammonty]

The compressions aren't great, but then they wouldn't be on a cold engine. I'd be surprised if you got 125 psi with a blown head gasket. Just service it!!!

[markthe45king]

Yeah I allowed for a cold engine - but isn't the issue the variation between them rather than the reading?

I'm working on the premise that buying the bits won't be dear, and i might need them at some point - i can only work on her on a weekend as i don't have a garage and if i do the service and she still doesn't work then i'm without a car for another week. Plus I'm ordering all the other bits anyway.

But I'm reading similar stories and seeing everything from replacing cracked dizzy heads to new valves being the solution, so i guess it's time to be systematic

[liammonty]

Granted the difference between 125 and 150 is greater than ideal, but I'd be surprised if that would cause the running problems you describe, particularly given that you say the car had been running fine and then suddenly didn't any more. The compressions will likely have dropped gradually over a longer period. I think it's possible to overthink these things. It's quite possibly something as simple as the points have closed up, but you won't know until you check them

[simmitc]

Yoour compression readings could be due to a gasket problem but it is unusual to fail between 2 & 3; it's usually 1 & 2 or 3 & 4. It could be worn valves or even incorrect valve gaps meaning that that the valves are not seating; but none of this really fits with your original description of the problem. It's simple enough to check and adjust the valve gaps and should be done as part of the service. I suspect that a full service will cure most of your problems. One thing that I forgot to mention in my first response was to replace the condenser as part of the ignition service. You could also check that battery connections are tight both on the battery and on the solenoid and the other end of the earth strap onto the body. Also, is the earth braid under the gearbox properly attached at both ends?