The Fordson Tractor Pages Forum

the fuel tap on my super dexta does not have a primer on it,suspect previous owner fitted this.Possibly from another make of tractor.Anyway it works no bother but has a little leak.Should I replace with similar,cost is quarter of the price. Brian Cox,Perth, Scotland.

Where about is it leaking ? I managed to repair the tap on mine by removing the circlip that holds the screw, I then unscrewed the tap and replaced the Oring in it. Put a light smear of grease on it then refitted. I'm sure some of the other guys will confirm but I dont think your version of dexta needs the primer as it has a excess fuel button on the pump. My Super Dexta doesn't have one either.

All Dextas need a primer because, being an indirect injection engine, they need heat in the pre-combustion chamber to help with cold starting. The primer and heater in the manifold causes a flame to give that heat.

The excess fuel button increases the amount of fuel delivered by the injectors but does not help with heating in the cylinders.

many thanks guys, tomorrow will change o ring give it a little grease and hope for the best.

My Dexta 1964 had no primer bulb when I got it. Someone had changed it to a simple ON/OFF Fuel Tap.
I had no problem starting it in the spring, summer and fall. But in the winter it needed to be hooked up to a engine heater for 1 to 2 hours before it wanted to start.
So it dont NEED a primer bulb, but it got alot easier to start after I put one in

Winchester wrote:My Dexta 1964 had no primer bulb when I got it. Someone had changed it to a simple ON/OFF Fuel Tap. I had no problem starting it in the spring, summer and fall. But in the winter it needed to be hooked up to a engine heater for 1 to 2 hours before it wanted to start.

What are your winter temperatures - well below 0C I guess?

temperatures well below but no starting probs. new o ring, and a smear of grease, hey presto! job done.
thanks for all your help.

Brian Cox wrote:temperatures well below but no starting probs. new o ring, and a smear of grease, hey presto! job done.
thanks for all your help.

Silicon grease I trust!

Bensdexta wrote:

Winchester wrote:My Dexta 1964 had no primer bulb when I got it. Someone had changed it to a simple ON/OFF Fuel Tap. I had no problem starting it in the spring, summer and fall. But in the winter it needed to be hooked up to a engine heater for 1 to 2 hours before it wanted to start.

What are your winter temperatures - well below 0C I guess?

It ranges from about -5C to -25C. Most of the winter it stays around -15C
Trying to start it without it beeing preheated with a block heater was almost impossible, and I would drain my battery.
Now with a priming bulb I don't need the block heater, but I like to think it saves the engine being preheated a little.

But one thing I must say about that little diesel engine, it was very well maintained, old but starts like new :)

finally got the hang of smilies

Brian wrote:All Dextas need a primer because, being an indirect injection engine, they need heat in the pre-combustion chamber to help with cold starting. The primer and heater in the manifold causes a flame to give that heat.

The excess fuel button increases the amount of fuel delivered by the injectors but does not help with heating in the cylinders.

Hi,
Can anyone confirm that is how the starting 'assistance' is performed?
I have just bought a 1960 Dexta and either mine has a different setup or some bits missing.
I have the heater in the manifold and an unused union in the manifold. Not sign of any device for squirting fuel into the manifold.

Rob

Hi. You should have a pipe going from the fuel tap under the fuel tank, to the jet in the manifold.
Additionally there should be a primer bulb fitted on the fuel tap that you push to force fuel up to the jet.
You should have a 'heat' button on the dash which activates a coil in the manifold, this glows red hot, then you spray diesel onto this using the primer bulb, which creates a flame in the manifold thus heating the air drawn into the engine.

After reading Brians post I ordered a primer pump as my super dexta was never a great starter and I just got round to fitting it. It has greatly improved starting of it so thanks for the advice.

I found out later, the super dexta which mine is , has a little knob on the injector pump which you press in for priming and it releases itself due to the rubber collar on it.
I have replaced the rubber as it had gone a little hard over the years,working perfect although I haven't had to use itfor real so far. Brian C.

super dextas do not have a primer type fuel tap, nor do they have a pipe from tap to manifold

Brian Cox wrote:super dextas do not have a primer type fuel tap, nor do they have a pipe from tap to manifold

Mine does

sorry but mine does too

Does anyone know the size of the oring? mine allows considerable leakage out the stem, but I can't find the right size.

I actually ended up fitting a new tap, it's just a basic tap costs about ten pounds plus vat. I have a super dexta and have never had starting problems

rsweeney wrote:Does anyone know the size of the oring? mine allows considerable leakage out the stem, but I can't find the right size.

Don't believe there is an O-ring. Olive (ferrule) on each pipe, yes. See also parts list.