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  #1 (permalink)  
Old 10-05-2012, 02:17 PM
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Default Gurney Weslake 305 Problems

I have a '69 305 Gurney Weslake with 4 48 IDA's.

I can get it to idle fine but when I barely get into it it bogs and pops and cuts out and wants to die. I dont know much about these webers and i have heard many ways to smooth out the progression from idle to mains.

right now im sitting on 65 idle jets with 120 holders. I drilled out the original 70 idle jets to about .8 and it helped a lot but then went way too large and wouldnt run at all.

When I push past the hole it runs great all the way through 8k rpm so I know my mains are good.

I have heard about drilling the third progression hole but im not sure I want to do that just yet. I also heard about making the idle holders a bit larger. Any ideas?
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Old 10-05-2012, 03:19 PM
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I'd start again at 60 idle, 100 holder.

How far out was your idle mixture screw with the 65s?
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Old 10-06-2012, 09:53 AM
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1 but I'm pretty sure it's starving for fuel
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Old 10-06-2012, 12:15 PM
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Do what Gaz64 suggested, set all mixture screws at 3/4 - 7/8 of a turn open. If it idles ok at 800-1000 RPM but pops as the throttle is opened THEN it is lean. Leave main jets and associated air correctors alone until idle sytem problem is resolved. If it has been setting, the gas could have gone bad. I had a situation early this past Spring with some bad gas that created what is best descibed as scale in the tank. Minute pieces of it repeatedly ended up plugging various idle jets, causing it to run on 7 cylinders.
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Last edited by Rick Parker; 10-06-2012 at 12:38 PM..
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Old 10-06-2012, 01:13 PM
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The gas is new and I've spent 10 hours plus cleaning all the carbs. I have had the screws out in those locations and still same result.

I know for a fact it is lean because if it was rich it would still run much better than it does now. When I went up in size on the idle jets alone my hole was getting smaller but never got it decent. I'm wondering if the jets are ok but when I open it up a bit I can't flow enough through the holder..

If I need to get the 100 and 60 I will and I'm going to open up the 120 holder a bit and see what happens keeping te 65s. I know my main jet air corrector and emulsion are good so that's not an issue.
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Old 10-06-2012, 02:17 PM
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If you open the holders it will become leaner (more air)
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Old 10-06-2012, 02:20 PM
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The 120 holder is giving you lean progression.

Start small on both, get it to idle at 3/4 turn out on the screws, then open the throttle with the speed screw to check progression.

If the 100 holder can't richen progression, even with a 65 or 70 idle jet, you'll need the third progression hole drilled.

This is more common with 48 IDAs on a little engine. Makes driveability a concern for a street car.
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Old 10-06-2012, 09:26 PM
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Are there any good places to order the holders online? I'm going to epoxy and drill till I find out the right size.

How exactly do you drill te third progression hole? I've looked up a few sites but each one says something different. Plus I don't want to do it wrong (if I have to)
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Old 10-06-2012, 11:01 PM
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This may give some guidance:

Weber progression hole differences

third progression hole--Who drilled their own?
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Last edited by Gaz64; 10-06-2012 at 11:04 PM..
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Old 10-07-2012, 02:52 PM
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302 cubic inches will RARELY require larger than a 65 idle jet. a 110 air holder will be about as lean as necessary too. Try a 60 jet with a 100 air holder. If the plugs are dark try a 110 air holder. If more fuel is needed go to a 65 jet and repeat. What emulsion tubes are you using?
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Old 10-08-2012, 09:08 AM
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225 air corrector
f16 emulsion tube
170 main

I think....im at the office so I cant pull them to make sure.

keep in mind this is an Indy car motor, not an ordinary 302..

I really appreciate the help
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Old 10-09-2012, 08:55 AM
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What size choke in the carbs?

Strange jetting for a 305.

To me, I'd say wrong tube, main too big, and air WAY TOO big.
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Old 10-09-2012, 09:33 AM
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42 i believe

I called inglese, told them what I have and they (chuck) recommended the 225 f16 170 so I got them. now that ive invested hundreds and still am having problems i have decided to get advice from other sources.
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Old 10-09-2012, 02:25 PM
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Can you give specs on the engine?
Compression ratio, camshaft, etc etc.


And just for comparison, although it's a sidedraught, they do work in the same manner, a 48 DCO 2/SP comes with the following:

http://www.ebay.com.au/itm/WEBER-48-...#ht_1335wt_907
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Last edited by Gaz64; 10-09-2012 at 02:30 PM..
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Old 10-09-2012, 02:51 PM
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i dont know the specs on the engine.

its an indy motor from 1969 made by gurney weslake from what i read 520 hp. i have a 400hp 1979 el camino and this motor is much much stronger.

ive researched all the specs and havent found anything yet.

its a very powerful and extremely high reving 305ci SBF 8,000 rpm+

you should hear it too
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Old 10-09-2012, 03:09 PM
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I dont see very many weslake engines. Are you saying it is a set of Gurney Eagle heads on a 302 short block. A real Indy engine uses a lot of differnt Parts. I know they ran them in 1968 not sure about 1969 . I hve been running a set of mk IV's in my mustang. I built the engine in 1992. I dont run webers .In 1992 I got bits and pieces from twm. Mark
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Old 10-09-2012, 07:54 PM
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I drilled te holders out to .7 and it ran much better but was pouring black smoke so I'm going to keep going up till its better.

If it ran well with .7 and 65f10 is it possible I may be high on the idle jets?

I believe it to be an Indy car motor.
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Old 10-09-2012, 08:29 PM
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So It should be very high compression. They ran on alcohol. Does this motor have a dry sump oiling system? Is it a new installation and you are just getting it running? What trans and rear gears? Is it in a Tbucket with a auto trans? Mark
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Old 10-09-2012, 08:52 PM
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Continue to open the air holder in steps to a max of 110, change fuel jet to .60 after each air holder change and note change then replace with .65 fuel jet and go to next larger air holder size. As a rule 1 step in fuel jet equals 3 of air corrector. Changes of air corrector allow smaller increments of adjustment once correct fuel jet is determined. Emulsion tube creates transition before WOT.
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Old 10-09-2012, 09:24 PM
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It doesn't have a dry sump. I bought the car recently and am trying to get it drive able. It has a c4 trans. I have no idea what gears. It's a jaguar rear end if I had to guess 4.10
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