Cold start button

This forum is about the Fordson Dexta, Super Dexta and Petrol Dexta.
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Bounce
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Cold start button

Post by Bounce »

I’m really pleased with how my Dexta starts and runs since it’s rebuild, but I’m wondering if there is a problem with the cold start button on the P4588 pump.

Like I said it normally starts no problem without any heat or the cold start button, but out of curiosity I’ve tried the cold start button on a couple of occasions and it did anything but help the engine start. Each time the tractor burst into life and ran really rough for 2-3 seconds, then cut out and it almost killed a freshly charged battery trying to crank it back to life. The last time I tried it, I pulled the engine stop to reset the cold start button after it had cut out and it started fine straight after.

Anything I should be looking into on the pump?

Old Hywel
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Re: Cold start button

Post by Old Hywel »

Take off the side plate and check that the rack is sliding freely, without any tight spots. A dousing from an oil can may help.
Not familiar with that pump on a Dexta, is it a Super?

Billy26F5
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Re: Cold start button

Post by Billy26F5 »

Sounds like the pump is in trouble, I think it will need an overhaul, but leave it for now. Does the heater work properly?
The P4588 minimec was fitted to all Dexta's from April 1962 (engine no. 1530251 onwards, and all in the 16xxxxx series before June 63, which are the Super Dexta ones), NP Super Dexta's have the P4696 minimec's (16xxxxx series after June 63).
Sandy
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Bounce
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Re: Cold start button

Post by Bounce »

I’ve been in touch with the company that supplied the reconditioned pump, they have not heard of this problem before, but think it may be something to do with the return spring on the cold start button as it should reset as soon as it starts, which it is not. The tech I spoke to was hopeful that even though it’s a few months out of warranty there should be no problem with getting it sorted by them FOC so I’ll get it sent off to them and see what they find.

The fuel line for the cold start heater had been removed and I never replaced it as I’ve heard too many time about it leaking fuel into the sump and I also struggled to find a suitable primer tap for under the tank, but I do know the glow plug works. Would there be any difference just squirting a bit of diesel into the intake manifold through the butterfly valve with a syringe on a cold morning?

Billy26F5
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Re: Cold start button

Post by Billy26F5 »

You shouldn't have a butterfly valve in your engine (as you have a minimec), but it shouldn't be a problem provided you can ensure no dirt can get in. The original system was to allow operation from the seat while starting, which allows for quicker starting. For some reason the correct Dexta fuel tap with primer is not easy to find, there was also an on-off tap on the manifold itself on later engines which was described elsewhere (viewtopic.php?p=58512#p58512) and a spring-loaded ball on earlier ones.
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Bounce
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Re: Cold start button

Post by Bounce »

I got my terminology wrong there, you’re right enough I don’t have a butterfly valve, what I meant was the on off valve you describe. I’m hoping that a squirt of diesel through that tap would serve the same purpose.

Billy26F5
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Re: Cold start button

Post by Billy26F5 »

It will, that's what the original system did, but to ensure you avoid running diesel in the manifold I recommend you squirt the fuel in once the heater has warmed slightly, as then it shouldn't pour down into the engine. Doing this is much easier when you can do it from the seat, it also allows you to squirt some in as you turn over which starts the engine almost immediately.
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Emiel
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Re: Cold start button

Post by Emiel »

Hi,

This is what I’m thinking about. Sick if this leaking fuel tap etc this might be an improvement.

https://histoparts.com/h28689-primer-pu ... on-dexta/3

Rgds

Emiel
Best regards

Emiel

N 1937, E27N 1948, 8N 1949, E27N 1950, E1A Diesel 1953, E1ADKN PP 1956, Dexta 1959, NH Clayson M103 1964

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