Idle To Low?

[Guest aidankinnell]

Once my pinto gets up to temperature I've noticed the idle tick over often results in the car sputtering and eventually turning off.

 

It seems to run fine the rest of the time, starts first time and warms up nicely with a bit of choke (although none today!). It's just when it gets up to temp I need a little bit of throttle whilst stationary just to keep it ticking over.

 

So, looking for thoughts......

I was planning on adjusting the idle speed screw very slightly (I'm not far off it being ok) but wasn't sure whether to touch the mixture as its running fine when on the move.

 

2L pinto running 32/36 dgv carb

[Guest 2b cruising]

What colour are your plugs after a run. If they are sooty then you need to adjust your mixture at running temp.

If they are sandy colour it can be either timing or tick over speed. White coloured points to a week mixture, or once again vacuum side leek.

Older engines used to run smooth with everything else right at around 600 rpm. Still ok to set them faster than that, say 750 rpm.

It depends on what cam is in as to what your timing should be set at.

With some cams it is impossible to get a smooth tick over.

With your symptoms it points to either rich running or air leek on manifold side of carb. ie, carb gasket, manifold gasket, open vacuum tube.

[Guest aidankinnell]

Just checked the plugs, 4hrs after my run, they have sandy grey tips. Hope there isn't a leak, can't hear anything as I rev, I have done in the past (2 yrs ago when building the car) but that was all sorted.

 

Running a standard road cam, new, put in about 300 miles ago last year.

 

Just quite annoying as it seems to run fine when moving but stopping and cutting out is just embarrassing! How to look cool in a 7

[Guest 2b cruising]

What is your idle speed?

Sandy grey sounds a little week. Sandy gold is what you need.

That's mixture screw out or anti clock a bit.

Mark the position of mixture screw now. Then try to adjust to get smooth idle.

You might need to speed up idle a bit first to stop it stalling when adjusting. Then adjust down if you get it running smooth.

Also, unlikely but if you are still on point system, it will be worth checking cleanliness, gap and dwell angle.

Edited June 13, 2015 by 2b cruising

[Guest aidankinnell]

Idle with full choke is about 1200, once warm and on a run it drops to about 600-800rpm but chugs

 

I'll take a look at the mixture asap

 

Thanks!

[Guest 2b cruising]

Would be worth a carb stip and clean out. Especially clean out the jets properly.

Easy enough job. If not confident enough, take pickies as you go.

[Guest aidankinnell]

Would you recommend this if the carb was new on when the cam was done?

 

Happy to give it a go it worthwhile!

[Guest 2b cruising]

Oh didn't read that part of your thread.

It could still be worth a look. Take the jets out and have a look through them. If clear reassemble.

Just try giving it a bit more fuel first. That's outwards with the screw. This won't cause any damage as it is a week mixture that does that.

If it is working your engine should start running smoother as you turn. I don't mean wind it like a clock, just slowly listening to the engine tone as you go bit by bit.

[Guest mcramsay]

Before you go touching the mixture I would get the car hot and then spray some wd40 over the inlet manifold, carb and vaccum hoses and listen for a change in idle speed, this would indicate a leak on the inlet side as mentioned. If it's only a small leak then it may be masked when the car is heating up with the choke on. But at idle with no choke it's enough to upset the mixture enough. If you have a leak and you try to tune it out by richening the mixture you will cause your self more issues. It may well not be a leak at all. But its just a quick thing to check

[Guest aidankinnell]

I'll give the wd40 test a go. Kind of hoping it isn't an air leak, especially gasket/manifold as I really don't want to be taking things apart! Down to pure stubbornness rather than anything else!!

[Guest aidankinnell]

Just to add to the post....... Got the kit all warmed up this evening but had to hold the revs around the 1000 mark to stop it cutting out. This meant that when I got out to spray wd40, the car died! Get a mate coming round to assist at the weekend, or I'll force the idle speed up a little whilst I test for leaks

[Peter Bell]

Have you checked the idle jets are clear?

[Guest aidankinnell]

Was going to be second on the list once I had checked for air leaks

[Longboarder]

I was planning on adjusting the idle speed screw

Maybe I'm missing something here but that should be your first action. DGV adjustment is not complicated. It's a new carb and the idle stop screw is unlikely to be set correctly for your engine. There's not much that is adjustable on a DGV but the idle screw stop screw is (and float height and idle mixture screw). I can't think you run any risk if you fiddle with it. The choke (manual/electric/water operated) has a cam that opens the primary throttle butterfly a little but when up to temperature will not longer be doing that. I would only start stripping the carb, checking jets, checking for air leaks if a thorough twiddling (not just a little) of the idle stop screw has no effect.

 

Nigel

Edited June 18, 2015 by Longboarder

[Guest aidankinnell]

Thanks Nigel. Just so I've understood this, you're essentially saying as its a new carb that I should:

 

- adjust idle speed to achieve a sound tick over

 

- if needed, adjust idle mixture

 

- possibly investigate float hieght

 

-if all else fails, then check jets, strip carb and clean etc. and investigate any leaks (not present at higher revs)

 

The carb has only done a few hundred miles so I would be worried if the jets were dirty/clogged already

Edited June 18, 2015 by Aidan