Author Topic: Weber carb set-up (Read 151764 times)

scottly · « **Reply #275 on:** May 05, 2013, 05:54:19 PM »

I used some of that silicon hose on my Corvair turbo, and it was much more pliable, but a bit pricey.

Thanks. I'll go that route the next time I pull the carbs.

Tintop · « **Reply #276 on:** May 06, 2013, 09:31:31 AM »

BPellerine - you've got a PM. They're in CA.

BPellerine · « **Reply #277 on:** May 06, 2013, 05:29:51 PM »

working all day so only get to computer in the evenings but I am greatfull for any info brian.you guys treat newbies very well thanks. bill

Tintop · « **Reply #278 on:** May 10, 2013, 06:16:59 PM »

Thought I would post the Weber results from last weekend's 'test & tune' there, rather than in my sidecar thread.

jets & parts used for sessions:
> mains 135 / airs 185 / emulsion tubes F11 / pump jet 135 / discharge 50 / idle F950 / chokes 34 / auxiliary ventri 4.5 / stacks 50mm

Overall the engine was stronger & sharper than last year. Did develop a misfire at the end of the last session; loose exhaust clamp to blame.

Once warm it would idle at 1 to 1200rpm, but would 'load up' after a while. Plugs were light tan, with a small darker area on the exhaust side of the tip. Carbon around the outside edge. Part throttle transition was very good. You could idle through the pits, and then just roll it on, and there was no flat spot. I can likely clean up the idle some more now, given I now have a working base to start from.

Not sure on the top end yet. Feels good, but seems to fall off a cliff @ 7K.

scottly · « **Reply #279 on:** May 10, 2013, 07:30:15 PM »

On your dyno chart last year, the power peak was at 6600 RPM, and the torque peak was at 6000. The motor went rich beyond the chart at 6200. Once again, try the 125 mains.

Tintop · « **Reply #280 on:** May 10, 2013, 07:54:28 PM »

That dyno run was done with 140 mains, 180 airs, & F9 tubes. I'm running a lot leaner now.

Would need to do A/F again to really compare.

scottly · « **Reply #281 on:** May 10, 2013, 08:06:32 PM »

When will your next test and tune be? With your setup, I would imagine you could swap mains in only a few minutes? If so, try the 125s first. You will know in a short time on the track if it's a move in the right direction or not.

BPellerine · « **Reply #282 on:** May 16, 2013, 07:03:24 PM »

got my carbs today! they look great.they came with single pull linkage mounted on the bosses that frank talked about.the manifold has no makers name but it is sweet.carbs are 38doce25s with another marking jo? have checked some jets as follows
idle 45f9
115 main
f41 emulsion
main venture 29
cannot find air correction size any tips?
these carbs and manifold look like they were together for a long time original kit maybe?no sign of wear and tear on screws etc.I don't think I could have done better finding something this old and complete.I am really happy and look forward to making these run.bill

scottly · « **Reply #283 on:** May 16, 2013, 08:24:45 PM »

Hey Bill, you promised pictures.

After Tintop's experience, I would check the size of the accelerator pump jets, as well as the accelerator discharge jet. The size of the air correction jet should be marked on the top, but I have seen idle jets with no markings. In any case, the air correction jet has the greatest effect at high RPM, and is much less sensitive than the main jet: a change in main jet size is equal to about 3 sizes in air jet.

BPellerine · « **Reply #284 on:** May 17, 2013, 10:29:09 AM »

pictures are on photo bucket have to figure out how to post them.bill

BPellerine · « **Reply #285 on:** May 17, 2013, 10:38:10 AM »

http://i2.photobucket.com/albums/y33/pellersw/2829E129-CDC8-4D81-9354-C05D0776281D-4923-00000474C9913559.jpg

BPellerine · « **Reply #286 on:** May 17, 2013, 10:52:51 AM »

I took them apart to have a look at manifold and free things up a bit.looking back at your post scottly I was looking at the air corrector holder not the jet got more checking to do.I don't have a manual so I am being careful until I am familiar with them.bill computer keeps updating while I am posting today

Tintop · « **Reply #287 on:** May 17, 2013, 08:35:16 PM »

Quote from: BPellerine on May 17, 2013, 10:52:51 AM

I took them apart to have a look at manifold and free things up a bit.looking back at your post scottly I was looking at the air corrector holder not the jet got more checking to do.I don't have a manual so I am being careful until I am familiar with them.bill computer keeps updating while I am posting today

Get yourself a copy of the Haynes Weber manual (green cover). It will speed up the learning curve, and help avoid costly mistakes. There are a couple on Ebay.

http://www.ebay.com/sch/6000/i.html?_nkw=Haynes+Weber+Manual&_vxp=mtr&_rdc=2

scottly · « **Reply #288 on:** May 17, 2013, 08:37:57 PM »

Bill, I only see one picture?

Retro Rocket · « **Reply #289 on:** May 17, 2013, 09:22:19 PM »

BPellerine · « **Reply #290 on:** May 18, 2013, 01:12:09 PM »

http://s2.photobucket.com/user/pellersw/media/8A7734DB-873E-4B06-B648-6E055901B091-4923-00000474E26C4B74.jpg.html

BPellerine · « **Reply #291 on:** May 18, 2013, 01:21:34 PM »

BPellerine · « **Reply #292 on:** May 18, 2013, 01:26:25 PM »

hope this posts bill

BPellerine · « **Reply #293 on:** May 18, 2013, 07:41:55 PM »

I may have found the reason these carbs were sitting around.The carbs were not sitting flush on the manifold due to the cover for start lever fouling the manifold.did not want to but I had to trim the manifold ever so little in this area to make carbs sit flush.This would explain the black goo that I found on the mounting gaskets.They are a composite gasket much like auto exhaust gaskets.Studs are also a little long as they are pretty close to pump jet towers so I will have to address those.I did not think for a moment that this would be plug and play!bill

scottly · « **Reply #294 on:** May 20, 2013, 06:07:11 PM »

I don't even have the start lever covers installed; they were never hooked up or used, so they are just excess weight, IMHO. Be sure to check the flatness of the carb mounting flange on the manifold, in case the bolts were over-tightened in an attempt to close the gap due to the interference.

Tintop · « **Reply #295 on:** May 20, 2013, 06:57:55 PM »

+1 on the starter cr#p. Just remove it, there's a cover plate available for the 40's, maybe something for the 38's too. When these are setup right you don't need it (them). The sidecar starts from cold - three twists of the throttle, and hit the starter. Same with the Cortina race car, and the Lotus 7.

754 · « **Reply #296 on:** May 20, 2013, 10:39:13 PM »

When they are low on gas, or it has not yet filled the carb,or very cold they are nice to have..even if you only use one of them .

Tintop · « **Reply #297 on:** May 21, 2013, 04:43:42 PM »

Even on a very cold day the Elan +2 (mechanical fuel pump) would start without them. Just needed to let it turn over a bit, then pump the pedal. Problem with the starter circuit is you have to shut it off ASAP, or the thing will flood. Never liked them.

BPellerine · « **Reply #298 on:** May 21, 2013, 08:06:37 PM »

have replaced too long studs with stainless bolts and spring washers.the po had too much non threaded stud sticking out of manifold and was compensating with cupped washers and thick rubber washers so not a lot of pressure was put on carbs.even if it was the carbs would not come flush with manifold.I Checked both surfaces with straightedge and they are good.scottly I saw the picture of your carbs with covers removed and thought about it but even if I don't use them I will always have the option.any ideas for fuel line setup?
thanks bill

scottly · « **Reply #299 on:** May 21, 2013, 08:14:07 PM »

I have the two fuel inlets routed to a tee, then to the fuel tank.

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Author Topic: Weber carb set-up (Read 151764 times)