Fuel problem or bent shaft.
- As the plug was fouled: Did you try to move the idle jet all the way in and turn it slowly out 1/8 of a turn each time? (Had too large , 65, idles on my V8 and some of the plugs never fired because they needed only 1/4 of a turn out; all the others 1/2.)
- Have you tried using the air bypass to overcome the bent shaft (if there is one?) to overcome the balancing problem?
- Have you checked tha corresponding valve/lobe/lift to see if it's correct on the ctlinder in question? (I once had a wrecked camshaft with some of the lobes gone south- very hard, indeed, to get the carbs balanced.)
- In terms of a linkage creating troble: Do you use 2 (one at each bank) idle set screws and a return spring?
I have sorted out the linkage. I replaced what was there with a very simple system (see my gallery) that works well. I also straightened the shaft so that should take care of that problem. I am pretty sure the original problem (dead cylinder) was caused by the bent shaft. Like I said in an earlier post, I also found that my intake gaskets were leaking. I had the “old” Fel Pro 1262 without the steel reinforcements. I am changing them out now with 1262-S.
Prior to the cylinder dropping, the engine was running okay. It was still rich on the idle circuit, but seemed to run well after 2500RPM. It made plenty of power from idle on…I am just tired of changing plugs every couple of months. I KNOW it is not right, but can be with the proper jetting.
Finally after what seems like months (I guess it was!!) my car is back on the road! I finished the manifold and carb install yesterday and cranked it up for the first time after work today.
The car runs MUCH better; no dead cylinder, no missing. It is still a little lean at the transition (2200-2300 rpm) where I am getting some slight popping and sneezing. I am currently running .60 idles, .80 holders, 1.20 airs (changed from 2.05) 1.45 mains and F-16 E tubes (Changed from F-7). Mixture screws are all right at ¾ turns, fuel pressure 2.5 lbs.
I may try .65 idles an see if that richens up the transition…Any thoughts? Also, I think I need to set the floats as I know I am leaking some fuel past the butterflies after shut down. Any one know where I could buy a gauge?
Did we ever discuss the punishment that owning a Weber setup was? Don't even answer I remember it well, the resume with the gunship maintenance sort of removed that requirement. So glad to hear it is runnin' well.
Aircraft maintenance will defiantly teach patience…Especially the troubleshooting aspect. Of course I have 37 years of aircraft experience under my belt and most problems I have seen a couple of times before. These Webers are a TOTALLY different ballgame. I am a rookie when it comes to them, but I am learning!! And even having some fun doing it!!!
Appreciate this is an old thread but wanted to pass
On my thanks for helping sorting a dead cylinder running 48 IDAs problem.
Did all the obvious spark ,leads , plugs rotar and caps. Determined issue was fuel so cleaned idle jets and still cylinder would not fire 🔥!!😤
Solution : turned out idle jet on carb corresponding with dead cylinder by 1/4 turn and bingo !!
Thank you again
Lloyd
Quote:
Originally Posted by Caprimaniac
Fuel problem or bent shaft.
- As the plug was fouled: Did you try to move the idle jet all the way in and turn it slowly out 1/8 of a turn each time? (Had too large , 65, idles on my V8 and some of the plugs never fired because they needed only 1/4 of a turn out; all the others 1/2.)
- Have you tried using the air bypass to overcome the bent shaft (if there is one?) to overcome the balancing problem?
- Have you checked tha corresponding valve/lobe/lift to see if it's correct on the ctlinder in question? (I once had a wrecked camshaft with some of the lobes gone south- very hard, indeed, to get the carbs balanced.)
- In terms of a linkage creating troble: Do you use 2 (one at each bank) idle set screws and a return spring?
Lloyd, if I may - what was your total turns out on the offending carb? I'm still chasing issues with a no-fire situation on my Father's car.
Justin
Quote:
Originally Posted by Lucia289
Appreciate this is an old thread but wanted to pass
On my thanks for helping sorting a dead cylinder running 48 IDAs problem.
Did all the obvious spark ,leads , plugs rotar and caps. Determined issue was fuel so cleaned idle jets and still cylinder would not fire 🔥!!😤
Solution : turned out idle jet on carb corresponding with dead cylinder by 1/4 turn and bingo !!
You have lots of experts and opinions being posted. Most of these people are way more talented than I ever was on motors and problems. After reading about 15 entries, I stopped, but maybe someone has posted this thought.
Your opening sentence was you had a popping and backfire and to me that sounds like it could be a valve train problem like a valve not adjusted (locking nut backed off) or a bent push rod.
I know nothing about your fuel injection system but one time on one of my BMW fuel injected motorcycle, I knocked off the throttle cable on the throttle body flange and did not catch. The bike started and it sounded absolutely horrible (of course it was running on one of two cylinders) and backfiring and making all kinds of racket.
So could there be something loose on your throttle linkage not letting the throttle body open on that hole? And or pull the valve cover off and check for a loose rocker arm or bent push rod on that cylinder.
I am like you. Hard to imagine your motor could be damaged especially when a good engine builder did all the work. Hoping it is something simple.
Cobra Make, Engine: Berry Cobra ,Tremec 5 spd . 408 windsor , double A arm 9"rear
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Run a smaller plug gap , if they are carbon fouled you can heat them up with small butane torch , (hope you have good electronic ignition and coil ) set gap , if you have got the carbs right , go for a good thrash as the chambers will be full of carbon , then fit new plugs , I have got some jet type listing in a book for weber carbs , let me know what size engine and street or race , I will see if something is close . Cheers .
Lloyd, if I may - what was your total turns out on the offending carb? I'm still chasing issues with a no-fire situation on my Father's car.
Justin
Apologies for taking so long to reply Justin I’ve just seen your question
I started off by sitting the idle jet i.e. tighten it don’t over tighten and then backing it out a quarter of a turn at a time
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I remember it well, the resume with the gunship maintenance sort of removed that requirement. So glad to hear it is runnin' well.
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