Author Topic: Tuning Help Please  (Read 3408 times)

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Offline Milkman

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Tuning Help Please
« on: April 21, 2007, 07:58:15 AM »
This is my 1st post here, hi everyone! And guess what? I have a real problem too.  :D  This one has me stumped. I put my '66 beetle back on the road today. I just finished replacing the distributor with a 019 W/pertronics, new spark plugs. Set the timing at 30 degrees total advance at 3000RPM. Synced the dual webber 34 ICT's & set the idle at 850RPM. It starts ok, idles a touch rough, but decent.  It revs up poorly & bogs out at about 3200RPM, pops a bit from the carbs (both a different times) Just put in a tank of fresh fuel too! What could my problem be? The only thing I havn't done is adjust the valves yet, but I did that before I parked it in the fall. Could it really be that simple? Any ideas? She can barely get over 60kph right now!

Greg

Offline Milkman

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« Reply #1 on: April 21, 2007, 03:39:47 PM »
Ok, I'm going to start at the begining so that you know what has been done....


1966 Beetle, 1600dp, dual 34 ICT Webbers, 009. Parked last fall, minimum amount of fuel, added fuel conditioner, stored all winter indoors. Started up frequently during the winter, ran perfect.

2 days ago, taken out of storage & ran perfect. Filled tank with fresh fuel. Removed carbs & manifolds, changed spark plugs. Re-installed carbs with new manifold gaskets. Changed linkage arms to shorter ones. Replaced all fuel lines & filter. Swapped 009 to a 019 with pertronics. New blue coil. Set timing, synced carbs. Runs like crap under load, idles fine & revs up ok, but with a stutter.

Today. Set valves, some were tight, some work ok but generally all were good. Double & triple checked timing, good. Tried different total advance settings, no change.  Double & triple checked carbs, good. Or at least close. Swapped the 009 back in as someone recomened, no change. Put the old blue coil back on, no change. Tried another set of plug wires, no change.

When I test drove it seemed to pop from the L.H carb & tail pipe. Sounds like a lean back fire. Also noted I was running a little hot according to the CHT gauge, around 400. Sprayed a little brake clean around both carbs where they met the manifolds & where the manifolds meet the heads. Seems like the idle goes up a touch when I spray the L.H. manifold/head. So obviously I created a vacuum leak when I had the carbs off. I will be repairing that next. I remember having to notch the R.H. intake slightly where it met the head when I originally installed these carbs, maybe I have to do that to the L.H. side as well.

Would that vacuum leak cause this thing to run as poor as it does? I can barely break 60kph & it takes a LONG time to get up to that speed.



-Greg

Offline josh

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Tuning Help Please
« Reply #2 on: April 21, 2007, 10:03:20 PM »
vac leaks are a nightmare, especially with dual carbs, they will cause lots of problems. I won't even go there. I bet if you re-gasket your problem will dissapear.

good luck
55 ragtop T1
56 kombi T2

Offline Hansk

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« Reply #3 on: April 21, 2007, 10:19:45 PM »
Vacuum leak would have it's greatest affect at idle.  Sounds kinda like a fuel delivery problem. Both carbs actually getting fuel?  New shorter linkage arms giving full throttle?
Big fat black fastback

Offline egspot

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Tuning Help Please
« Reply #4 on: April 22, 2007, 01:55:08 AM »
Quote
Vacuum leak would have it's greatest affect at idle.  Sounds kinda like a fuel delivery problem. Both carbs actually getting fuel?  New shorter linkage arms giving full throttle?
That linkage ussue was a major change and the carbs may not be opening all the way. I will also check if all four cylinders are firing. You may not be firing an all four.

Offline josh

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« Reply #5 on: April 22, 2007, 06:58:55 AM »
I agree vac leaks affect idle but if you fire it up and try and tune the carbs compensating for a leak that you don't know is there you can get it to idle fine.  
55 ragtop T1
56 kombi T2

Offline Hansk

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« Reply #6 on: April 22, 2007, 09:41:48 AM »
Sorry Josh , didn't mean to seam like I was questioning your reply.I was just responding to milkman and you beat me to it.
So milkman , any luck?
Big fat black fastback

Offline dannyboy

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Tuning Help Please
« Reply #7 on: April 22, 2007, 10:23:36 AM »
i agree with hans, this seems like a fuel prob...
check your fuel pressure, and check fuel flow to both carbs maybe a line is pinched off...
what kind of pump are you running?
how is the fuel filter, maybe as it sat something gummed up, something gummy could have shook itself loose when you took the carbs off...
 

Offline G-dog

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« Reply #8 on: April 22, 2007, 02:55:52 PM »
There's a  gauze filter in the spigot of your fuel tank that can fill up with crap & limit fuel flow if you've not cleaned out your tank in a while .Unfortunately you  really have to remove the tank to get at it....
1967 Beetle (the only year worth considering)/Berg 5

Offline Milkman

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« Reply #9 on: April 22, 2007, 04:22:51 PM »
Thanks everyone!  I was in the garage until midnight last night taking care of the vacuum leak. Pulled the L.H. carb & manifold off. Took out the gasket & set the manifold back in. Sure enough, didn't sit flat on the head. There is a small raised boss that protrudes enough to keep the manifold from sitting flat. A few seconds on the bench grinder with the manifold took care of that issue!  ;D Still runs terrible, but no more popping out the carb. Time to check timing & tuning again. I did double check to see that the carbs still had full throttle, so I'm good there. Replaced the fuel filter yesterday & my tank has no screen in it (I know, I know) Stock style fuel pump. There are no kinks in my fuel lines, but I'm thinking maybe one of my new steel lines had a small shaving that I missed, guess it's time to blow those jets out....

Wish me luck! I'll get this figured out yet.

-Greg
 

Offline Milkman

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« Reply #10 on: April 30, 2007, 09:11:25 PM »
Well I finally got it figured, just not sure exactly what I did.

Started it up & started pulling off plug wires to see what would happen. Guess what? The engine was only running on the 2 L.H. Cylinders! How weird is that. Didn't seem to be a fuel problem, but I had to take the carbs off to pull the plugs & wires, so I took out the jets & blew them out anyway. Plugs were good, so I installed a brand new set of Bosch plug wires & took off the new crap Taylor ones that were on there. Re-assembled & fired up. Perfect! Finally runs proper. Did a base carb sync & set the timing. Went for a little tear around the block, back to normal! Now I just need to take care of the cooked R.R. wheel bearing & the rear brakes.   ::)

Never ends does it?  ;D Good thing I love my VW's!

-Greg

Offline bochintz

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« Reply #11 on: June 17, 2007, 12:30:18 AM »
you just never know
til you take it all apart
and check every little thing