Weber carb fitted to a Ford Courier 3.4 ltr. engine has just started running away with high revs

i wouldnt due to the diesel having a heavier built gear box than the petrol but there is adaptor plates that will allow them to fit

Carb flooding is an indication there is a problem with the floats, valves or adjustment but your description is not of flooding but rather suggestive of a haze of fuel being expelled from the carb barrels. My apologies in advance if I have misunderstood.

This phenomenon is fairly typical of high performance engines where the intake valves close so rapidly it causes a shock to the column of incoming air that rebounds through the intake manifold and out through the carb resulting in the characteristic fuel haze. If the fuel haze is allowed to disperse and be lost to the next intake stroke the engine can be down on power, use more fuel and be an increased fire risk.

Some manufacturers use an air box around the carb intakes to perform this function and to help silence the intake roar. Serious designers specify ram pipes or bellmouths large enough to contain the haze and prevent it dispersing and some use both methods and fit an air box over the ram pipes to silence the roar, contain some filtration and allow an intake hose to be fitted so air can be drawn from a cooler area than high in the engine compartment...

I hope this helps.

this is caused by mixture getting past the idle and being sucked into the combustion chambers and being ignited by the hot spots and combustion pressures
Very common on early english cars and some american cars
The japanese carbies had a solenoid valve that fitted into the idle circuit so that when the ignition was turned off , the solenoid closed off that idle circuit and prevented the problem
you may have to "play " with the idle mixture screws to get a better mix so that the mixture is too rich to run on or change the weber to a model that has the solenoid shut off

Define "unit" please....

Ford Escort carb backfire Questions & Answers - Fixya

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Ford Escort cars & trucks carb backfire questions and answers. ... Backfire throughcarborator and engine stopped upon returning from store. ... Turbo conversion from 1995 on a CVH engine - engine cuts out ... I have a xr3 ford escort 1600 with a weber carb,itbackfires and spits fuel up Clean the Carburator completely.

I have a xr3 ford escort 1600 with a weber carb,it backfires ...

www.fixya.com/cars/t10838117-xr3_ford_escort_1600_weber_carb

Nov 17, 2011 - I have a xr3 ford escort 1600 with a weber carb,it backfires and spits fuel up ... Turbo conversion from 1995 on a CVH engine - engine cuts out.

All comments on Ford Escort CVH Straight-through exhaust ...

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Is your check engine light on?

Most rev counters of this type wire the positive wire to the contact points on the distributer and the black (negative) to ground.

buy a can of carb cleaner with the little red nossle
start the truck and take the can of carb cleaner and spray small amounts around the intake don't forget to also do the vaccum lines if you have a leak the engine will rev up ( thoes trucks with the 4.0 was good for doing that

richard is right
what ever has happened after you played at being electrician
Put it all back to standard then get advice as to how to do each part

Are you sure your idle ports ( size of pinhole) in carb aren't plugged with something? What happens if it starts to die, and you give it a quick squirt of WD-40 , down throat of carb?