Club 80-90 Forums

Afternoon all,

I'm Jim, new to the forum and new to owning (finally) a T25. I've recently got myself a 1983 last of the air-cooled Devon 2.0 CU.

Already spent hours reading over all the great stuff on this forum.

Got a problem with the left hand carb. It seems to be running horribly. I initially tracked it down to no idle adjustment screw!! Found it rattling around the engine bay. Put it back in, fully in and 1 turn back out. Still sounds horrible. Would it be that?

Also looks like the very top gasket has been badly fitted and some of it is poking into the top of the carb, possible leak?

I'm no expert but can have a crack at most things.

Do you mean the idle mixture screw? If so with the engine fully warmed up back off the screw then screw in until the engine just starts to falter then back off until the engine runs smoothly usually about 1.5 turns. Gasket could be badly fitted, some replacements are just badly cut to shape.

Oh dear, what a plonker, let me start again, got it completely wrong.

So it's actually the left hand SOLEX 34 PDSIT Carb and the screw i'm talking about is just above the nut that tightens the 'centre part' of the carb to the 'throttle valve' part of the carb, all according to the Haynes exploded diagram. Albeit the diagram shows the opposite side of where the screw I'm talking about is.

The carbs are paired idle and mixture is adjustable on the left carb, you need to balance the carbs and set the linkage before anything else really , I thought the Haynes manual described it Well ?

Right ok got you.

A little update, I just took the top off of the carb to have a look at things, also removed the retaining bolt for the main jet in the hope of cleaning said jet and the main jet is completely missing?!

Correct me if I'm being stupid, but that should definitely be there right?

You mean the accelerator jet ? Pictures?

Will cause over fuelling if it’s missing

Sorry for the delay, not had a chance to get out there.

So here is a photo of where the missing jet is:

https://www.amazon.co.uk/photos/share/Z ... Ao6FsUq6Qi" onclick="window.open(this.href);return false;


Here is a photo of the screw that I found rattling around the engine bay:

https://www.amazon.co.uk/photos/share/3 ... L95rqI4AkJ" onclick="window.open(this.href);return false;


Also should this hole arrowed here be blanked off as well?:

https://www.amazon.co.uk/photos/share/6 ... ayibnCXStc" onclick="window.open(this.href);return false;

Here is the tag number from the carb:

https://www.amazon.co.uk/photos/share/c ... smzfUxG0iw" onclick="window.open(this.href);return false;


Any idea what size jet I need to replace the missing one?

From info I've searched would 135 or 132.5 be about right?

Muchos gracias for help offered/given.

Where your arrow is pointing to the “missing “ jet is just part of the thread for the float bowl plug, the jet is at the opposite end to the arrow , undo the plug and look through the hole you will see the jet, the screw that’s had fallen out won’t really make any difference to running , no need for a plug in the hole you have arrowed in the base of the carb