T25 idle problems. Plus backfire

[jamespainter453]

Hi guys.
Some I'm having some problems with a t25 I bought
she is a 1984 watercooled 1.9 petrol with a Df engine and solex carb.
Now I've been plagued with idling issues. I have replaced the classics like the idle cit off valve and the fuel pump aswell as filters. But she still won't idle. She also backfires a fair bit.

So i have a few questions.
1 - I seem to be missing the timing marks! There's now a V or nick or anything in the main wheel. How am I meant to set it!
2. I found a part of the side of the carb that has notches in it and seems to stop the acceleration cable going all the way back. But it just sits on the lowest setting. If I physically move this part to the second nearest step the van will idle. But when I drive it it will stall at yellow lines and basically when ever you don't have the pedal down slightly. Should it be attached to something like a spring?? - have taken a picture and will n post on the next.

I'm also on the case getting a new dissy cap and rotor arm, though not sure why this models are so expensive ha ha

Any help would be great guys thanks!

[jamespainter453]

Hi guys. So after some reading I have found out that the part that I was talking about is the fast idle.
My question is that should it move. When I put it on step 3 the van idles well (if a bit fast) but when I press the accelerated pedal down it flicks back to past step one and so the van stalls.
I notice that the choke is also involved here I think. Could this be causing my idle problems?

Cheers for any help!

[CovKid]

The steps are directly connected to the choke. When choke is first on, the screw sits on the highest step. As the choke gradually comes off, it'll work round until screw is on the lowest step. The reason its not idling is because you have an air leak. Because air is getting in (probably via gasket under carb or up to and including inlet gaskets), the mixture becomes weak by the time it hits lowest step, and not strong enough to get a satisfactory idle. If you only have probs first thing (ie when cold), choke may need increasing. If it won't idle even when warm (ie dies at junctions or sitting in traffic), mixture is too weak (air leak being the most common cause). Hope that helps.

Weak mixture could cause backfire - as will leaky exhaust to some extent.

[mickeyflyn]

I also have an 84 registered df and had the very same probs as you and apart from discovering someone had changed the solex carb for a pierberg the idle prob was as ck said air leaks from vac pipes and gasket. now sorted and idles fine .

[ELVIS]

What is it timed to? IIRC (and you need to check) the DF is the only WBX timed at ATDC and not before.

[itchyfeet]

What is it timed to? IIRC (and you need to check) the DF is the only WBX timed at ATDC and not before.

Correct

[jamespainter453]

Ah guys, you heros. I will get on removing and checking the gaskets on the carb this weekend. In the mean time, is there any little tests I can do to check for leaks. I've read about spraying wd40 near the carb and listening for a note change. Would that give me any indication of an air leak.

It's good to hear other have had the same problem (well kind of ha ha) and fixed it. Gives me hope

Will keep you all updated

Many thanks
James

[jamespainter453]

Oh also as for the timing, she doesn't seem to have any of the timing marks! noticed a thread on here where someone had the same problem so I'm going to try and figure that out. I have a timing gun and have set timings before so half know what I'm doing there ha ha

Cheers!

[itchyfeet]

This is a dg, the outer rim of the pulley looks like it has two marks but its just the light, it actually only has one wide U shaped mark, that is TDC and yours should have that too, mine is painted with tippex, it will be hard to see if not.

As mine is a dg it has a 5 degree btdc v shaped mark on the inner rim of the pulley which is clockwise as thats the direction of the engine, 5 degrees is about 7mm around the circumference of the pulley.

A df needs to be 5 degrees atdc so the mark will be 7mm anti clockwise of the tdc mark on the inner edge of the pulley

If you really have no marks its becuase the pulley seal surface wore out and its a replacement pulley, you can get your engine to tdc by other methods and make the marks yourself.

Always worth checking the marks to the direction and dims above incase an incorrect second hand pulley has been fitted.

It's not stated but the corresponding alignment is the centre of the engine casing which is the right hand edge of that chunk of metal below the fuel pump, or the left hand edge of that chunk of metal stamped AP

No 1 cyliner to connect the strobe is the front right of van as you look from the rear.

cheers
Paul

[jamespainter453]

Hey Itchyfeet thanks for the info and pic, its just what i needed to get an idea of what im looking for.
Havent had a chance to look yet, but did manage to get the carb off after work and give it good clean before it got to dark this eve. It does seemes to have helped as the jets had a few partially blocked holes. Going to get a rebuild kit as some of the gaskets were a bit worn. Any ideas where is best?

Will get back to you on the timing marks when i next get a chance to.

thanks again for all the aswers guys!