Starting help please

[Dougie212]

Hello all

So I’ve finally got to the stage of firing Myrtle up. Aside from oil coming from the oil filter - which I half expected as the bowl was quite fiddly to get into place - I can’t get her to start. Ignition is turning on.. pull start and it turns over and sounds like it wants to start but doesn’t quite make it. I’ve checked the fuel pump. That ticks away and primes itself. I’m getting fuel to the float chamber. I did change the distributor cap and HT leads. I’ve double checked that when I moved them they are in the same position as before. When I do try to start it though it turns a few times then gives a ‘wurr’ type noise. Could anyone offer any advice or help as to what could be the issue. I initially thought it could be the starter motor. I do have sparks on each of the plugs - if I’m honest though, I was getting cold and a bit fed up and didn’t really pay much attention as to how strong the spark was. I felt the coil and it was getting quite warm - but haven’t metered it out to check the ohms.

I’ve uploaded a video to YouTube of the issue. The sound is on the video.

https://youtube.com/shorts/gF4OscvzKl0?feature=shared

Hopefully the link will work. As always.. any help and advice is hugely appreciated!!

Duncan

[simmitc]

On the plus side, it sounds like a healthy battery. The wurr sounds like part of the starter motor continuing to spin after the dog (Bendix) disengages from the flywheel. You would not normally hear it as the engine would be runnin. Silly question: You are using the choke when starting? Assuming yes, and that points gap and ignition timing are set correctly then double check:
Remove No.1 spark plug (nearest to radiator).
Place thumb firmly over the hole.
Slowly turn the engine by hand until you feel pressure building under your thumb.
Now look at the timing marks and continue turning the engine by hand until the mark on the pulley aligns with the central pointer.
Now remove the distributor cap and note to which terminal the rotor arm is pointing. Check that this HT lead goes to No.1 cylinder.
With No. 1 lead correct, check that remainder follow anti-clockwise 1-3-4-2.
With all correct, try starting.

[Dougie212]

Hi..

Thank you for your reply..

Not a silly question at all!! I am using the choke. But when this first started my initial thought was the carb. It’s all been off during the rebuild. I was chuffed when I saw it was getting fuel but there was an initial thought of mine that it might be carb related. I did pop an egg cup of petrol into the carb throat and no joy. I’ve also checked the choke cable - which is new - is opening the choke fully, which it seems to be doing.

I came away yesterday as I was getting cold but after Christmas I’ll definitely go and double check the points gap and ignition timing are okay.

I came away as I started to get a little frustrated as it sounds so close to starting..

Thanks so much for the suggestions!

[myoldjalopy]

"So I’ve finally got to the stage of firing Myrtle up." When I last fitted a new engine (years ago) I had the same symptoms as you. As luck would have it, a passing mechanic stopped and suggested the dizzy might be fitted 180 degrees out - he was right! So Simon's advice to check the timing is good advice.

[Dougie212]

That’s brilliant. Thank you very much. I’m going to have a look after Christmas. Really appreciate the responses. Merry Christmas all!!

[Dougie212]

Little update - had some time today and checked the HT lead positioning, the spark plug and points gap and all seems right. I’m getting a spark at all four plugs. I’ve checked the voltage at the coil and I get 10V which drops to 5/6V when I try and start the car. As in the video though, it turns it just won’t fire up.

I haven’t checked the spark from the coil - so will pop back out now and check it.

Is there anything else I should be checking please..? I’m trying to do it systematically. The only thing I have noticed is when trying to start it - choke is open and I do on occasions try and pump the throttle. The tone of the engine trying to start doesn’t change. Noticing that I closed the choke and same result. The tempo or the sound of the turn over doesn’t change. Is that something I should notice or just something I’m thinking should be happening when in reality…. It doesn’t.

Thanks as always!!

[Bill_qaz]

Pumping throttle on SU carburettor does nothing, you have no accelerator pump on this type.
Does piston in carb lift and drop using test pin?
Has the dashpot got correct oil and quantity?

[simmitc]

Is it a standard carb? There is no accelerator pump on an SU. The operation of the choke is that when you pull the cable, the jet moves down, away from the body of the carb. Is that how it's working now?

Is the carb piston moving freely?

You have checked the position of the HT leads and the gaps, but have you checked the timing to the marks? The air filter looks like a 948cc engine, so static of about 4-5 degrees BTDC should be a good starting point.

[Dougie212]

Thank you for the lightning quick answers..!!!

I have checked the timing against the marks also yes. The rotor arm was pointing at 1.

Yes, the jet moves down when I pull the choke. I’m a bit new to carbs so how is best to check the piston is moving freely? I’ve topped the oil up and the top is quite stiff to push back in and fasten.

[Dougie212]

I’m also maybe reading a bit too much but I don’t know if I’m missing an earth strap to the engine. I’ve checked my pre rip out pics and can’t find anything but then - the wiring was an absolute mess!!

Pic is attached but should there be a strap between the ground strap and the engine head bolt?

IMG_4780.jpeg (2.58 MiB) Viewed 14502 times

[svenedin]

Earth strap is from the gearbox to gearbox cross member on the Minor 1000. Since engine and gearbox are bolted together this is the “engine” earth.

Stephen

[Myrtles Man]

Get yourself a can of this https://www.ebay.co.uk/itm/156437807066 ... R6aw__2EZQ, squirt some into the air intake and try starting. If you're getting sparks at the right time and in the right places it should fire up thereby telling you that you have a fuelling problem. If it doesn't fire up, you have an electrical (sparks) problem.

[simmitc]

To check the carb piston, first remove the damper and the air filter. You should now be able to reach in with your finger and lift the piston all the way to the top. It should be a free and easy movement. Remove finger and the piston should fall back all the way with a clunk. There should be resistance when inserting the damper, but a slow gentle push should see it in and the final turns on the screw thread should be easy.

[geoberni]

I can't believe I'm reading this.....

I’m getting a spark at all four plugs.

I’ve checked the voltage at the coil and I get 10V which drops to 5/6V when I try and start the car. As in the video though, it turns it just won’t fire up.

I haven’t checked the spark from the coil - so will pop back out now and check it.

A 12v Battery at 10v is almost dead.
You're getting some 'Spark' so checking the "spark from the coil" is pointless; it's obviously working, at least as far as connections.

HOWEVER... 10v at the Coil which drops to 5-6v when cranking is like peeing into the wind; the spark you have is negligable and unlikely to ignite any fuel, especially at this time of year when the vapour is less...

The Coil should have full 12v Battery voltage, which should then only drop by about 1 or 2 volts when the engine is cranking over on the starter.

You've got a weak/knackered battery.

Simon was right on Tuesday when he said it 'sounds like a healthy battery' , it does, but it's a bit like finding Iron Pyrite when looking for Gold.
The Starter is taking all the power available in the battery to turn the engine over, leaving negligable terminal voltage to power the Spark.
The Coil is only a transformer converting the 12v into 20,000v or more, so your 5v is resulting in a spark of just half what it should be....

You said you've got Points, rather than Electronic Ign, so have you tried the Starter handle?
It might fire up on the Handle, because the 10v should be enough to give you a decent spark.

(That's the only shortcoming of having Electronic Ign; low battery terminal voltage stops it working, so starter handing often doesn't work)

Charge the battery and try it.....

As Stephen said, the engine return path is via the strap on the gearbox; if that's not fitted then you've really got problems as you're earth returning via heaven knows what, possibly the fuel line or something....

[Bill_qaz]

Agree with Berni comment but on you video sounds like the engine turns over on starter, fires throwing the starter out mesh but does not continue to run.
Try fitting a temporary wire direct to the coil input from the battery ( bypassing ign switch and wiring)and see if you still get the drastic voltage drop during engine cranking.

[oliver90owner]

I disagree with the Bernie comment re the battery being almost dead at 10V.. i would go further by saying it IS dead at that voltage. Many modern-day battery chargers would not even initiate charging, of a battery at 5-6V!

The rest of his post is spot on.

There is a most certainly a problem with the measuring equipment or the power supply through the starting system. I would go with the latter.

Often, if the battery voltage, at minimal draw, is 10V (more usually about 10.5V) there is a dead cell in the battery.

[Dougie212]

Thanks for your reply. I maybe didn’t update the post properly. I was cold and a bit fed up in the garage by that point. I was getting 12V at the battery. 10V at the coil and then the draw down to 5/6V when trying to start. My multimeter then packed in so I put it away for the afternoon. Battery is off and on charge so I’ll have another look at it on Sunday morning. Thanks all.

[geoberni]

I disagree with the Bernie comment re the battery being almost dead at 10V.. i would go further by saying it IS dead at that voltage. Many modern-day battery chargers would not even initiate charging, of a battery at 5-6V!

The rest of his post is spot on.

There is a most certainly a problem with the measuring equipment or the power supply through the starting system. I would go with the latter.

Often, if the battery voltage, at minimal draw, is 10V (more usually about 10.5V) there is a dead cell in the battery.

You're right, 10.5V is regarded as 0% Charge.
I was being overly polite/generous in my description of 10V, but I was allowing for him reading 10.**v, being somewhere under 11v after allowing for a small voltage loss over ancient wiring. I also assumed his video was perhaps taken when it was nearer 12v, but likely of reduced capacity...

Your own comment about battery chargers and what they will charge is not allowing for the fact that his reported 5-6v is whilst cranking; a charger would usually try to charge at 10.**V off load terminal voltage .....

[svenedin]

I agree that the battery is either discharged or knackered. If the battery was left for a significant period partially or fully discharged it will never be able to hold a healthy charge again due to sulphation of the plates.

As there is doubt, definitely check the earth strap is in place from gearbox to gearbox cross member.

I would suggest charging the battery and doing your tests again. If there is still a huge voltage drop on cranking then get a new battery. The reference figures I find for cold cranking voltage across the battery terminals is 9.6 to 10.5 volts.

By the way, how did you test for a spark? It may be that you can get a little spark to jump between the HT lead and the block but it is too weak to jump the spark plug gap (did you check the plug gaps are correct?).

Berni is right about the starting handle. When I was a student, my Morris often had a flat battery (knackered battery). I could start the car on the starting handle even when there was so little charge in the battery that the indicators could not flash let alone turn the starter motor. The standard points ignition will start the car at 10v or even less but not the 5 or 6 v that the OP gets when cranking.

Stephen

[simmitc]

I agree that a poor battery will cause problems, but against that, the video suggests that it is cranking OK, the engine fires once so that the starter disengages, but then does not carry on, even though the heavy cranking load has now been released and so current draw greatly reduced. Despite appearances, accurate measurements are still important. It will be interesting to hear the results with
(a) Freshly charged battery.
(b) Directly connected lead from battery to coil feed terminal - could be that the ignition switch is faulty.
(c) Easystart - available from any good motor spares shop, if any still exist.

One other thought: +ve or -ve earth? If converted to -ve, then are the coil connections the right way round? It won't make a big difference, but sometimes a marginal one is all that's needed.