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Reverend

It Ain't Running Right!

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Too much fuel consumption and dark plugs are caused by:

 

jets too large

fuel level too high

fuel pressure too high

 

 

Seems like we have been here earlier. Start from the basics again.

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I made a small tool from transparent pvc pipe, made mark on 29mm and 31mm and measured. First 2 carbs had exactly the same amount of fuel (29mm), rear one had tad over 31mm. I dialed it down but even after full turn, it did not lower the fuel level to 29. Fuel level screw on the last carb is over 2 threads higher than the first 2. Is that normal? Here are couple videos, this first one is taken right after i started it, it raises rpms well but you can hear that the idle is far from nice. It feels like its not running on all cylinders when i took it for a spin, after few mins, it felt better, but not normal.

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_194615_zpsgfjnfec5.mp4

 

This is just a test how it sounds inside, too bad on this you cant hear the burbling sound it makes when idling.

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_195141_zpssmuhj8ya.mp4

 

On this last one, engine is almost fully warmed and i slowly raise rpms. Im quite sure it spits out from the last carb. Tell me your opinions!

http://vid578.photobucket.com/albums/ss224/Spacereverend/20150414_195719_zpsqvdavzzy.mp4

 

I'm also worried about the engine shaking on idle, it shakes a lot.

 

Just reviewing the thread:

 

I just looked at the vids for the first time.  nice stuff

 

I see throat #3 spit 12 seconds into the first video when the rpms rise. Is this the throat that had the main jet separate (mentioned above)?

 

Also, the return line connected between carbs 2 & 3 could be causing the different fuel levels in carb 3.  Try to get a "T" on carb 3 and pull the return after that one. In the interim, you could try closing the return at the T between 2 and 3 so that there is no return to teh tank.  If your fuel pressure is ~ 3psi you should be fine for testing.

 

You should also spray starter fluid around all of the carb to manifold spacers to make sure no leaks are present.

Edited by Blue

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Of course it's "possible" that all six plug wires got damaged at the same time, but it's so unlikely that I'm comfortable saying it's statistically impossible.

 

 

There is a Vulcan amongst us!

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Fascinating.

:LOL:

Fuel pressure is way more than 3 psi, like 6 or 7, if i drop it any more, it starts to stumble like crazy... :(

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Maybe check your fuel pressure gauge?

 

Can you block off the return fuel path (dead-head configuration) and set the fuel pressure to 3.5 psi and see what happens?

 

This is the dead head config:

 

TerryBuffum-Jaguar-ParkinsonSpecial-BC.j

Edited by Blue

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I think i know why the fuel pressure gauge showed crazy numbers. I hooked it to the fuel line such way that it was at the "end" of the line, so no fuel would pass it. I need to get T-shape connector so i can allow fuel to travel pass it and measure the pressure then. OR just get a regulator with gauge..

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Hmmm. Another contradiction. It seems that carbs need craploads of fuel to run on idle and cruising speeds, but they starve when revving over 4500 rpms. Carbs sound like machinegun (popopopopopopopop) if i go over that...???

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Hmmm. There is problem at cylinder 6. When i was driving, it felt constantly like its not running on all cylinders all the time. This morning i started it, felt and sound strange. Took of cyl nr 6 plug off, and it sounded exactly the same. SO nr 6 is not working. Its getting fuel as the plug is wet, tested plug and it gives spark... Valves? I have to do compression test as soon as possible.

Edited by Reverend

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Did compression test. All cylinders were ~150psi.. i cleaned those small filters that are in each carb banjo fitting, there was some crap there but it did not affect. Here is couple videos of testing spark, is it strong enough? It only "activates" when its not touching the car, only from short distance, is that normal? Check out the second video for that

 

https://www.dropbox.com/s/vehu2cfjt228q3q/20150510_122131.mp4?dl=0

 

https://www.dropbox.com/s/f5fcxdzafaa57cj/20150510_121426.mp4?dl=0

 

So its getting fuel (put my hand over the rampipe and fuel cam pouring out), it seems to have spark and its getting air. Pressure is good and valve clearances are set. What in the name of lawd almighty is wrong with nr6?

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The spark in the first video looks a lot healthier than the spark in the second video. The one in the second video looks intermittent like it isn't firing rhythmically.

 

What was different between those two videos? Did you change something on the engine between the two?

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Well the spark is healthier because it does not touch the fuselage, thats the only difference. I bypassed the ballast resistor i had on place and now it gives spark normally, when the plug touches anywhere in the fuselage/engine. BUT it did not solve the problem!! :(

 

I measured that the new coil i have, has 3 ohm resistance and old one had 1.8 when it worked, maybe i need to get more powerful coil as well even it is not the problem anymore (i think..?)

 

I disassembled the rearmost carburator, everything looked okay, sprayed craploads of carb cleaner to every possible place imaginable. I wonder could the brake booster somehow affect cyl nr6??

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Pic of your dizzy and the "small box" you described. Sure sounds like ignition .

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Give us a picture of your manifold setup showing the vacuum taps

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I know it's a step backwards in technology, but what are the chances you can go back to a good ol' simple points system?

 

Just long enough to make sure everything is working properly? And then you can start modifying again?

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Dead head and set fuel pressure to 3.5psi. You can then focus on the carbs and not worry about fuel.

 

Correct.

Set at 3.5 max. You are flooding at anything more.

THEN start working on setting up the carbs correctly.

Did I miss the part where you gave the venturi size and jet sizes?

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32mm choke, 50/100 idle jets (50F9), 115 main jets (too small), F11 emuslion tube and 170 air corrector. My fuel pump should max out at 4 psi, so its not flooding at all, i get only ~2 psi to the fuel regulator. But cylinder nr 6 aint starving either as far as i know, if i put my hand over the throat, it blurbs fuel out.

 

Here is picture of the whole engine bay if that helps figuring out.

 

post-19126-0-14933300-1431319505_thumb.j

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If I am looking at this right your manifold does not have the balance tube connecting all the throats. Correct? If that is the case disconnect the booster off of the #6 intake and plug the port. See if that helps. If the booster is badly blown it may be causing the lack of draw on #6

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I have found the booster can leak and braking can get longer but the brakes work without the booster, just not as well. If your legs are strong it wouldn't be as noticeable, but a vacuum leak could really throw off that carb.

 

What Madkaw said ^^^^^ It's an easy experiment

 

Blues idea is good too, just a little more work

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I swapped the carbs, synced them and now the situation is this:

 

Driving above 1200-1500 rpms is okay, no extra vibrations, accelerates well, some occasional pops from the carb (maybe 1 or 2 in 5 mile trip)

 

idle below 1200 is UTTER CRAP, i feel like im in the wheel of some super cammed V8 that shakes all over but as soon as i raise rpms, it runs steadier.. Could it be manifold leak or something? I tried with and without the booster, no noticeable difference to me. Except in braking.. heh. Im afraid the engine mounts will suffer if i let it idle, with SU's the idle was smooth as baby butt.

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i know absolutely nothing about your carb setup, but in my experience w/bike carbs idle shake was often caused by them being out of sync at the idle circuit. i assume you've synced them with a flow meter of some kind? could also be a clog or imperfection in one of the idle circuits (crap in a jet or burr in an orofice) leaning out one idle circuit's fuel delivery even though the air flow was constant at the bellmouth. again, just some basic multi-carb advice - not specific to your setup.

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