Dans Dexta Project Again

This forum is about the Fordson Dexta, Super Dexta and Petrol Dexta.
Post Reply
DanielV
Not Quite Blue Yet
Posts: 30
Joined: Wed Mar 14, 2012 2:41 am

Dans Dexta Project Again

Post by DanielV »

Been a while since I have posted on here but I have finally go back to work on my Petrol Dexta. This time I have striped it down and painted it, as I went I fixed problems and replaced many nuts bolts and washers.

This time around I have done the following:
New paint Bareco sent me the oddest colour blue but I used it as I need the tractor up and running ASAP
Rebuilt the steering box with new seals the inside was nasty no wonder I needed so much muscle to move the wheels!
New steering wheel and top nut the old one was broken and welded to the top nut
Fitted the MF tacho and new cable had a little bit to mod to make it work
Repaired the holes in the auxiliary fuel tank and re installed it
Replaced the dodgy ignition setup it had a ballast resistor to bring it to 6v and a commodore ignition set
Rebuilt the distributor new points cap and a good clean
New rotor and distributor cap
New coil
Flushed the radiator
Fitted a choke cable
Rebuilt the carburettor
Got a seat cushion best spent money yet

Now the tractor looks better although I have not done the nose cone grill, wheels and cowl yet as I have a lot to do for them but the rest is done nice and shiny (except when I have taken nuts and bolts off to fix more things after paint.) even though it is not really the right blue it looks ok. The steering is a thousand times better I can steer with one hand now and the seat cushion is by far the best thing I brought for it now I can drive the tractor in comfort no longer fighting the steering wheel and gaining a very big pain in the rear end from the metal seat.

Now the problem that I hope one of you can help with is with the throttle setup I have spent 2 days and suffered many burns trying to adjust all the links, I have followed the books and diagrams from the M35 and TE20 and I still cannot get it correct, first problem is that I cannot get the idle down below 700/800RPM it just dies I think that I still have an air leak at the throttle shaft?? I was thinking of taking it to a carb store and getting them to ream out the shaft hole and bush it?
I am not too concerned about the idle the big problem is getting the throttle and governor linkages right the biggest problem is when I throttle up if I don't hold the throttle open the governor kicks in and pushes the assembly closed again I tried to slash with my hand holding the throttle at the correct position but this is going to drive me nuts. Third problems is that the governor setup while slashing is not wonderful it seems to wait too long in my opinion before trying to compensate and when it kicks in it revs it hard and backs off again so it seems to surge under load, I have tried adjusting the screw in the timing cover to adjust the tension on the governor but this had little affect, is this normal under changing heavy load on a Dexta?

Looking at the below pics I was wondering about a couple of things, below the air intake is a shaft and spring bolted to the wall that rotates with the throttle one end has a spring setup of some kind that the throttle link runs next to the tappet cover over the manifold however the end of the shaft that sticks out from the tractor looks like something is designed to go on the end and a pin to retain it, what should go here? also the throttle stick under the steering wheel I cannot use a key to locate it properly as this would have the stick against the top of the steering wheel for some odd reason?

now some pictures:)

Steering box
Image
Image
Image

Throttle Linkages
Image
Image
Image
Image
Image
Image
Image

Nick
True Blue
Posts: 712
Joined: Thu Jun 03, 2010 8:52 am
Location: Somerset UK

Re: Dans Dexta Project Again

Post by Nick »

Hi dan, looking good! That colour doesnt look too far off, ive been painting parts for a major this weekend :)
Oh yay, look, another seized bolt! Lets get a hammer.....and some kano.....and some cider!

Brian
Grumpy
Grumpy
Posts: 5216
Joined: Wed Apr 16, 2008 2:07 pm
Location: Norfolk, England.

Re: Dans Dexta Project Again

Post by Brian »

I had similar problems with Dotty, she would run happily at tick over when first started but once she had been running for a short while, the revs went up and she would not shut down to tick over. Governor would work however.

Last year I fitted a Sparex carb overhaul kit for around £15.00 and now she runs like a sewing machine at all revs.

From your pictures the rod from the carb to the governor seems a bit short,

Image

The spare hole in the cross shaft is a mystery, nothing extra is shown in the parts book.
Fordson Tractor Pages, now officially linked to: Fordson Tractor Club of Australia, Ford and Fordson Association and Blue Force.
Brian

DanielV
Not Quite Blue Yet
Posts: 30
Joined: Wed Mar 14, 2012 2:41 am

Re: Dans Dexta Project Again

Post by DanielV »

I know that I must have a carb issue however I think I still have a throtle assembly issue as well?
Should the throtle assembly move free when the pressure is removed from the 2 springs at the front of the tractor the one from the governor and the one in front of the U-bolt? If I set the throtle to fully open and then push on the governor towards the back of the tractor the throtle moves towards the idle this means that when I have the tractor running and I increase RPM the governor kicks in and this causes the throtle assembly to turn back towards idle, the only way to keep the RPM up is to hold the throtle open at the steering wheel myself.

Also below is the cross shaft at the air intake, it looks wrong to me as the spring installed looks like an old valve spring to place risistance on the throtle so that the governor's movement will not affect the throtle possition?

Is it possible for someone to send photos of the throtle assembly from the steering wheel under the fuel tank throught the wall below the air intake all the way to the governor? I see lots of photos at the governor but no photos showing the links going back to the lever?

I am likley going to just buy a new carb as i am sure that the body on mine is worn bad as I did put a kit through it and this stoped the fuel leaks but I still have air leaks at the shafts, i figure the cost of having a shop ream and bush it all properly will probably not be worth it compared to a new one?

Image
Image
Image

Jerry Coles
True Blue
Posts: 541
Joined: Thu Apr 17, 2008 9:09 pm
Location: Camerton, Bath, UK

Re: Dans Dexta Project Again

Post by Jerry Coles »

To check if your throttle shaft bearings are worn try squirting a little petrol onto the shaft ends. If the engine note changes then its sucking!
Jerry
Jerry Coles
Camerton, Bath, UK
West Highland White Terriers, Dexta's, E27N's and DUKW's

DanielV
Not Quite Blue Yet
Posts: 30
Joined: Wed Mar 14, 2012 2:41 am

Re: Dans Dexta Project Again

Post by DanielV »

I sorted the throttle shaft issue out now and the governor no longer pushes the throttle closed when I gun it.

I have rebuilt the Carb and I am sure that it is not sucking at the throttle shaft before the rebuild I could blow air through the shaft while it was in, after a new shaft and bushes I cannot do this now however the problem remains although I have a new development, the carb is now cold and condensation forms on it now even after running the tractor for an hour!!!!!!
Next thing I did was adjust the tappet clearances which needed to be done as these were not right most had nearly no clearance, once I did this the motor sounds better and smother. At this point I ran out of ideas and decided to block a breather hole in the side of the carb (photos below) after this it now idles perfect in fact I can drop the idle to about 200rpm and it ticks over better than ever. I set the idle to 400rpm adjusted the timing with a light to 5 deg BTD mark on the fly adjusted the forward screw on the carb to get it to run best at 400rpm, it runs perfect now throttles up nice and smooth and sounds better than ever, only concern I have is that I am sure that the breather hole should not be blocked so can I assume that I still have air being sucked in from another location? also why is a breather hole in the side of the carb after the butterfly in the throat?? I would have thought the carb is sealed and only air from the cleaner and from the adjustment screw would enter the carb??

any help would be appreciated as I do not want to spend the $309 that the local shop wants for a replacement carb for an MF35 but after all the work I have put into restoring this tractor I will certainly go and spend the money if I cannot work this out.

Image

condensation is more obvious in these 2.
Image

Image

pjjms
True Blue
Posts: 213
Joined: Tue Dec 15, 2009 10:11 am
Location: Nelson, New Zealand

Re: Dans Dexta Project Again

Post by pjjms »

That hole has a blanking plug in it on my tractor.

pjjms
True Blue
Posts: 213
Joined: Tue Dec 15, 2009 10:11 am
Location: Nelson, New Zealand

Re: Dans Dexta Project Again

Post by pjjms »

On the condensation, I have another petrol tractor (Nuffield) that does that. In cold weather it even builds ice on the start of the manifold. Does not seem to bother it at all though.

DanielV
Not Quite Blue Yet
Posts: 30
Joined: Wed Mar 14, 2012 2:41 am

Re: Dans Dexta Project Again

Post by DanielV »

pjjms wrote:That hole has a blanking plug in it on my tractor.
You give me hope, I wonder if this should be blanked on our dexta tractors and open on the MF?
Can any one else confirm if its blocked on their tractor?

pjjms
True Blue
Posts: 213
Joined: Tue Dec 15, 2009 10:11 am
Location: Nelson, New Zealand

Re: Dans Dexta Project Again

Post by pjjms »

I don't think it will be open on a MF. The hole just allows drilling of fuel gallery that includes a 90 deg angle during manufacture, and must be blanked. This is done on a lot of parts and often you see a small ball pressed into the hole to blank it after drilling.

I think on this carb that gallery leads from the idle mixture screw to a small hole just above where the throttle butterfly sits when in the closed position.

DanielV
Not Quite Blue Yet
Posts: 30
Joined: Wed Mar 14, 2012 2:41 am

Re: Dans Dexta Project Again

Post by DanielV »

I could almost cry right now, 2 weeks trying to get it to work and a missing blank on the carb has been the problem from the start.

pjjms
True Blue
Posts: 213
Joined: Tue Dec 15, 2009 10:11 am
Location: Nelson, New Zealand

Re: Dans Dexta Project Again

Post by pjjms »

Tears of joy I hope, you've cracked it, it's going!

Post Reply