T25, top speed 45 MPH

[zxr750]

Thanks BOXY,

I see you have a similar set up as me, 2.0l CU, Solex 34 PDSIT not sure what dizzie I have, will check tomorrow.

I'm in the process of cleaning up a set of Solex 34 PDSIT & getting a bit cofused how to set the throttle plate.

What gap, choke off choke on, Haynes is confusing.

[dbz864]

hope I haven't missed something on one of the posts, sounds like your clutch is slipping.

[zxr750]

No clutch slip. I have a carb & timing issue. Thanks.

[bigherb]

I'm in the process of cleaning up a set of Solex 34 PDSIT & getting a bit cofused how to set the throttle plate.

What gap, choke off choke on, Haynes is confusing.

Choke must be wedged in the off position.

If the carbs are off the vehicle unscrew the throttle stop until there is a gap and the throttle plate fully closed then with a depth gauge measure the distance between the bottom flange and the throttle plate, screw in the throttle stop to open the throttle plate so the distance increases no more than 0.1mm.
Or if the carbs are on the vehicle, disconnect the accelerator drop linkages from the carbs. Unscrew the throttle stops until they are clear then screw in till they just touch then one further turn.

[zxr750]

Hello,

I'm having trouble setting the timing but first, to let you know a few things I've done in between.

Performed a compression check,

No 1 = 140/2 = 155/3 = 135/4 = 140.

Replaced air filter, plugs, fuel filter.

Cleaned out carbs & set throttle plates has per Haynes, basic setting on the mixture screws, 2 1/2 turns out, Which gave a big gain in power.

Checked timing as BOXY suggested but it doesn't run right, its currently set @ 24 degrees BTDC @ idle & pulling the best its done since I've owned it.

I did double check that the timing light was on no 1 lead, & the notch on the pulley.

Is there any thing that could throw the timing mark out that much?

Thanks.

[BOXY]

You should be able to set the ignition to about 6-8' BTDC at idle.

It should only advance to 28' BTDC at +3000 RPM. How are you checking the RPM? Once you've got the carbs set you should be able to wind the idle down to 700-850 RPM.

[zxr750]

Through the timing gun, it has the digital RPM display.

[BOXY]

Does your timing gun also have a setting for the advance? Check if that's set right?
With the engine running at a constant idle speed you should be able to set the advance at any point between +28' and 0' by turning the dizzie. You will probably have to increase the idle speed the closer you get to TDC to keep the engine running. How close to TDC can you get the ignition point before the engine cuts-out?

[zxr750]

Yes the gun is set to zero.

I would have to take it past TDC before it cuts out.

I've set timing to 6 degrees BTDC @ around 850 RPM with both vac lines on & it runs like crap, flat spot & hesitant @ low revs.

If I was to increase the revs to set the timing it would move it even further away from where it runs best, which is turned anti CW about as far as it goes.

I'm currently seeing a return of 10 to the gallon & a max speed of 65 MPH, so could do with some serious help.

I've put some pics on showing the timing mark on the pulley, the distributor because there nothing on it to identify it, & one of the left of the engine bay because I don't think it as the idle stabilizer, the wires are permanently plugged together.

[BOXY]

6 degrees BTDC @ around 850 RPM with both vac lines on & it runs like crap

With both vac lines connected the timing should be 6' ATDC, not BTDC.

Try sucking on each vac line with the dizzie cap off and check the advance / retart is working. One line pulls it anti-clockwise the other pulls it clockwise.

Check you've put the timing mark in the right place. Turn the engine over by hand until the rotor arm is pointing to the tiny mark on the dizzie's rim. (should be below where the no.1 HT lead connects). When they're lined up the timing mark should be at 0 degrees.

Your idle stabiliser is missing. It should be here (ignore the arrows, they're there for another posting)



The dizzie will have a number on the other side. Check this list for a CU engine parts numbers.

http://www.brick-yard.co.uk/VehicleSpec ... lnmbrs.htm" onclick="window.open(this.href);return false;

[zxr750]

Both vac lines working correctly.

[BOXY]

You can see my timing mark on the 6' ATDC position. It's hard to tell for sure but comparing your photo to mine it looks like your timing mark is in the wrong place in relation to the key-way. The timing mark on my van was so hard to see I only found it by putting the engine to TDC and using a LED torch to light up the back of the belt pulley.

[zxr750]

I see, so I'm at leased 12 degrees out for a start.

The nick on the back of my pulley is to the right of the notch in the center of the pulley, sort of in line with the bolt that side of it.

[BOXY]

I don't know why VW decided to make the timing mark to difficult to see. You can see a scratched mark on the front of the pulley, to the left of the purple arrow, on my picture. I guess a previous owner had a problem setting the timing on mine in the past.

[zxr750]

OK I will try setting timing to After TDC.

Going to need some help setting the carbs when I get this sorted, how you fixed?