We're Back!

[simonknee]

Hi all,

After 3 years off the road I finally saved up enough money (-cough- remortaged -cough-) to get back on the road. Gauges overhauled by Speedy, Engine rebuilt by Miles Wilkins. Sterring Wheel re-covered by Nick Fulcher. Bits and bobs from Matty and Chris N. CV rear end by Spyder. Stub-axles by Pat. Electrical loomy bits by Auto Sparks. Exhaust re-welded by LongLife. Much effort (plus f'ing and b'ing) by me!

350 into my first 500. Hurrah!

First (ish) issue is/was weeping from the rear weber, rear choke only (nearest windscreen). I've overhauled them with the weber service kit. Tried type26owners trick of idling with the main jets out and the observed that the floats were all ok. Nice trick too. With venturi and choke removed (engine not running but pump on - fuel press. reg. set to 1.5psi) I could see fuel collecting at the base of the throttle disc. Checked in all the jet holes and saw a bit of junk had gotten under the accelerator jet. Removed and it now seems good. However could this have been the reason? If the accelerator jet is not properly seated will fuel leak in here even when at idle?

cheers

[simonknee]

Hmm not sure I did fix it. Seems that the rear weber is still weeping some fuel from both chokes so I checked out the float. It was wrong as per the 8.5/15mm spec. Odd since pretty sure it was right when I reassembled. Could over pressure from the facet have bent this? I ask since I ran without a pressure reg for a couple of 100 miles.

There is some mention of weeping ocuring until the webers are set "right" in the forum. However I am struggling to find Keith Franck's write up on all his threads. The links he posted in 2005 no longer work. Can't see anything on GGLC either. As Keith said in 2005 searching this forum is a bit rubbish. There doesn't appear to be any form of advanced search, or is there???

[rgh0]

Have a look at the yahoo group "sidedraftcentral" for all of Keith's wisdom on Webers these days.

The Weber and Lotus manual method of setting the float height is useless in terms of the precision required you will be lucky if you get the fuel level correct to +/- 2 mm. You need to directly measure the fuel level at 25mm below the top face where the jets screw in and get it to +/_ 0.5mm.

One other issue with Webers leaking fuel is due to leakage in operation between the main jet fuel supply and the secondary venturi that fits into the body as the spring that side loads the secondary venturi in place can loose tension.

regards
Rohan

[simonknee]

Hi Rohan,

Strangely despite the fact I still get emails from yahoo group lists I can no longer log in. Oh well. Made a new profile with yahoo but a search on "sidedraftcentral" produces exactly zero results. Is it a super secret club

Edit: it's a super secret underscore - sidedraft_central - thanks Mike

[r.agnew]

AFAIK Keith is known as "dcoe_tuner" on sidedraft central.


Rob
'71 Sprint

[rgh0]

http://autos.groups.yahoo.com/group/sid ... l/messages

try the link above - I forgot the underscore

cheers
Rohan

[simonknee]

Rohan,

In one of your earlier posts you mention a pipette is better than a vernier for measuring the float level. However on removing the weber top cap I am confused as to what the datum points for the either technique are. Is there an elaboration on this at the sidedraft forum? (not had my invite yet).

A reset of the float level has improved my weeping but it is not cured. Since the floats are likely originals for this set of 40DCOE18 I suspect a more accurate technique than the 8.5 mm drill bit is required!

Like the weak spring thinking as the fuel doesn't weep out the trumpet but rather out of the gap between body and venturi. You see it flowing over the trumpet stud/bolt.

[rgh0]

Yes you need to measure the fuel level by removing one of the main jets. The depth from the top surface that the jet screws into down to the fuel level should be 25mm +/- 0.5 mm.

The easiest way to measure this is with an acrylic rod polished at both ends and with a slip ring on the outside of the rod. insert the rod in the jet hole push it down with the slip ring resting on the top surface. looking down the rod it will go dark wihen the rod touches the fuel surface. Remove the rod being careful not to disturb the slip ring location and meausre the length from the bottom to the slip ring with a suitable set of calipers. If its not the correct 25mm take off the top and adjust the float tab until you get the fuel level right. You need to scoop out a little fuel each time you do a trial so it gives the floats a chance to open the valve and refill to the newly set level.

You can do the meausrement with the tail of a set of calipers by just increasing the length slightly until it is jsut wetted on the tip but hard to judge this right and not put the tip in to deep. Another way is to dip in a tube or pipette and blow gently down it until you here it contact the fuel and start making bubbles and use a slip ring in a similar way to the acrylic rod to mesure how far down you went.


cheers

Rohan

[simonknee]

I checked float level with a vernier. Both carbs are at 29.5mm. I set the float with an 8.5mm drill bit. Curiously there are many references out there to 1.14inch (29mm + 4.5mm). How does this equate to the 25mm recommendation.

Certainly the fuel looks to be 6-7mm rather than 2mm below the lower shoulder.

?