Low idle?

[jimbope]

Hi Guys!
Finally got the Van Motd last week - now just the odd fettle now again now shes on the road to try and keep her there!

Been tuning the engine - done a lot of research on Interweb ref static/strobe timing. Now back in the day when I had beetles I would always set timing by A) Turning ignition on. B) Turning engine over by hand (till No1 gonna fire) and then listen out for a click. Set the click to about 7 or 8 degres BTDC by tweeking the dizzy and voila. Now with my freshly built 1600 SP I have done the same. This however has a 009 dizzy (otherwise stock apart from an awesome :!: monza 4 tip). Now my question is - in order to get the engine to idle I have had to screw the idle control screw on the lever arm RIGHT in with only a few threads on myside of the arm? If I advance the timing it runs faster at idlel but pinks its tits off in 4th gear on a hill. So basically have set timing at correct setting to avoid pinking (bad for engine!) but now have a very low idle - in fact it can cut out when slowing for junctions. A quick dab of the pedal usually saves it and then it will idle. Am i doing anthing wrong? The mixture screw in the side is set at 2.5 times out from in (when I overhauled the carb).
The throttle cable only seems to come thru the fan housing and into the screw barrel just enuff to be honest too (sure on the bug there was about 10mm of cable sticking out of the barrel when tightend!)Not sure if this is related but thought would mention it!
Any pointers would be greatly apreciated! ALl the pics i have seen of carbs the idle screw seem to be about half way in! I have a solex 30 pict 2.

Cheers

 

[Blake7even]

Set the timing according to 27deg at 3000 rpm. Timing light only on 009's
Next remove 009, sell and buy an SVDA. 009's are 'ok' on twin carb but a Porsche dizzy was never going to play well on a 1600 VW motor.
On the Solex 'single screw' pict 2 the idle screw is on the throttle arm. Adjust away. Mine likes it at about one turn from in on the air screw.

 

[jimbope]

Cheers - I have put a wanted post for an original distributor!

The only thing is why is my idle speed so low with the idle screw turned almost all the way in? Surely if timing is set statically then idle should be the same with any dizzy - I see that if the ignition advance curve is not suited to stock carb etc you would run into difficulties when revving engine!

How much effect does the air screw in the side have on idle? I have set it as recomended to 2.5 turns out - most online guides state that should only deviate by 1/4 turn in either direction?

 

[Blake7even]

Your right about that deviation, but old carbs have wear so you have to compensate. Especially if it's a single air screw carb as these have often been screwed in too hard opening the other end up. It Is a single screw on the left side yeah? Not a two screw?
If single screw, screw it in and the revs will raise, unscrew until they just drop. On this type of carb this mixture setting only affects idle, lean/rich running at mid to main is governed by the jets alone.

 

[jimbope]

Hi mate.

Had a play with the air screw (single screw type carb). Doesnt really seem to have a major effect on idle speed but if screwed in too far then engine can falter.

To get the engine to idle at all (very low/lumpy) (engine warm/choke off) I have to have the idle control screw in the throttle arm screwed in as far as it will go. Surely this is wrong? There should be greater scope for adjustment? I would expect the engine to be revving its tits off!

I dont think the engine has any induction leaks - have sprayed WD40 round all inlet points.

I need to raise idle as engine sometimes cuts out at roundabouts/junctions and is getting a bit dangerous!!

Any other ideas? Maybe the carb is worn? (has had new gasket kit etc..)

Cheers in advance!

 

[jimbope]

Right, just spent an hour or so on van so back to basics!

Checked + adjusted valves (new heads now done a couple hundred miles so expected deviations)

Took time and adjusted points. checked igntion advance with stobe and timed to 32 deg max advance. Any less and the engine wont idle at all. This equates to about 7.5 deg at idle (low and lumpy!) I tried to set it to 27 max but would just die when the revs dropped. Hopefully the engine wont pink at this setting.

Im fairly confident all basics are covered - However I am not running heat risers on the engine as the when rebuilding the tubes where rotted out and solid with carbon - easiest solution was to cut legs off manifold - couldnt find a one piece SP manifold at the time! Now maybe Im thinking that was a mistake I the manifold seems to be icing up - yes even today! I have made sure that the airfilter is now feeding from the heat tube buy cable tieing flap in winter setting. Maybe this will help!

So now Im thinking I have a multitude of issues effecting low speed running (remember my idle screw is as far in against throttle arm as possible)

1 - Heatrisers (used to use a IMDU many years ago but they seem to have dissapeared?Been out of the scene for a few years)

2 - 009 dizzy in stead of original. Will run lovely at idle if I advance the timing beyond recomendations!

3 - Carb (30 pict 2) an unknown - although has been thouroughly blown thru and degreased and a new gasket kit fitted.

The engine on the open road runs lovely ( cuisring at 50/50mph - doesnt seem to want to go much faster! presume this is normal?)- its just the stalling I need to sort!

Any pointers on this would be great

James

 

[noddy]

try this, http://www.vw-resource.com/30PICT2.html" onclick="window.open(this.href);return false;