Morris Minor Owners Club

Maurice was a bit naughty today. Have not driven him for a fortnight and he did not want to fire up. The battery turned the motor over very quickly but nothing. Long story short, did the usual checks on ignition, etc and found that the choke mechanism was not freeing itself - the "jet" underneath the carb had to be manually pushed in after the choke was released. After that the car started fine. Bit strange that it did not start from cold with the choke pulled but so be it.

My question is whether I need to strip the choke mechanism down, oil it up etc such that it frees itself normally. Or is there something alse amiss?

The jet is pushed back up by a return spring on the body of the carburettor when the choke knob on the dashboard is pushed back in. The jet should move freely in and out of the carburettor body. Perhaps the jet is sticking or the return spring has become weak, displaced or has broken.

https://sucarb.co.uk/linkage-parts/retu ... rings.html

Stephen

Ok, it looks like some dismantling to investigate is the next step.

Nickol wrote: ↑Fri Aug 23, 2024 9:51 pm Ok, it looks like some dismantling to investigate is the next step.

The choke linkage is just attached to the black plastic part of the jet with one screw if remember correctly. Be careful removing that screw because there should be a very tiny washer under the head of the screw. With the lever detached you can gently move the jet in and out to see if it is sticking. Be carefully doing this as you could bend the needle if you pull the jet out too far and then shove it back in. You can also move the choke lever to determine whether the return spring is working. If the jet sticks you will have to ascertain why. Possible causes: dirt, sticky fuel residue, bent needle, jet not correctly centred. Bent needle or jet not centred would also affect normal acceleration so probably just dirt or a weak return spring/stiff linkage.

Stephen

Before you dismantle anything spray some WD 40 or similar around the jet and pull the choke lever in and out a few times. It all gets very dry under the carb especially as it is over the exhaust manifold. A bit of lube may do the trick.

That is an idea - I will do that now. I have also noticed since that with the choke cable pressed fully in, it does not completely close off causing the idle speed to be faster than it should be. That is probably also worth a good spray as well.

I don't like WD40 as it is not a lubricant. It dries and gets sticky so that it makes things worse. Initially it frees things up only to eventually make the situation worse. I would suggest carburettor cleaner followed by a light oil.

Stephen

It seems to have done the trick with the WD40 and for good measure have squirted a bit of engine oil too. Several pullings and pushings of the choke cable has led to the choke mechanism freeing itself up.

The carb does look a bit manky (is that an engl word??) as I have not done anything to it apart from when I first purchased the car in May 2011. It has done ca. 25.000 km since then.

I will take the carb off during the cars winter hibernation and give it a good clean then.

thanks for the tips.

Good alternatives to WD40 are GT85 and Duck Oil. I use all three depending on the application.

philthehill wrote: ↑Sat Aug 24, 2024 1:24 pm Good alternatives to WD40 are GT85 and Duck Oil. I use all three depending on the application.

PlusGas is also very good. It is like Diesel in an aerosol.

Stephen

philthehill wrote: ↑Sat Aug 24, 2024 1:24 pm Good alternatives to WD40 are GT85 and Duck Oil. I use all three depending on the application.

I will ask some friends in the szene what the equivalent is here.

"I don't like WD40 as it is not a lubricant"

WD40 seem to disagree. Quote from their website.

"The Multi Purpose Spray with 2000+ Uses

Over 2,000 uses, so it is a household essential that you can use for a whole manner of things. Easy-to-use, the unique formula dries quickly and leaves a thin, clear coating when you want to protect or lubricate a surface. WD‑40 Multi-Use Spray works just as well when you want to clean away stubborn residue too."