Diag: Recently running again but having some running issues?

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Martin Benade
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Re: Diag: Recently running again but having some running iss

#61 Post by Martin Benade »

If it is a trip with a wife and kid, you should go along. These cars are very patient.
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Harold Singh
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Re: Diag: Recently running again but having some running iss

#62 Post by Harold Singh »

Harold Singh wrote:
Mervyn Hyde wrote:How did you go Harold?
Ran out of time to do much. Worked late Friday and didn’t get to start. Saturday I aerated and seeded the yard before I got started. This afternoon I removed all the fuel. Put fresh ethanol free fuel in and after I checked the screen and cup under the tank and blew out the lines. Fuel was clear and no sediment was present.

My wife said she’d let me out of the pumpkin patch trip to check timing and work on cars tomorrow.

Checked timing with the lamp and made a slight adjustment and then rebalanced the carbs to account for that. Made a red dot at the advance marker to be sure I didn’t mix it up with the white mark at 5’ BTC. May have made a slight difference or maybe I imagined it. Still has a lack of power and seems to be loading up or something.

Fresh fuel and clear screen and lines. Can’t see any more junk in the jets. Double checked the firing order again (50th time).

7.41 volts at 3k rpm.
Harold
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Mervyn Hyde
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Re: Diag: Recently running again but having some running iss

#63 Post by Mervyn Hyde »

Curiouser and curiouser Harold. Just to be clear, you checked the timing at around 3000 rpm and got around 30 degrees?

If so, then reading the entire thread again, fuel flow. Are the fuel bowls filling/running at the correct level on both sides? Ron has his excellent level gauge which I use often but there are other ways to check. Maybe you have already checked this aspect?
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Paul Ahnell
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Re: Diag: Recently running again but having some running iss

#64 Post by Paul Ahnell »

Harold: +1 on Merv's recommendation to check level of fuel in bowls. I had similar crummy running conditions - loosing power badly under load. I tried EVERYTHING to cure problem. Finally, using both Ron's fuel level widget plus a manual confirmation check with a ruler I found the bowl for #3 & 4 cylinders was a skoshe low at ~19.7mm. By using a combination of bowl valve shims I raised the fuel level ~1.25mm and brought it into spec of 18.5 +/-1 Doesn't seem like much but it cured the problem of running out of steam when under load at high rpms. Tedious, but satisfying.
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Dave Wildrick
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Re: Diag: Recently running again but having some running iss

#65 Post by Dave Wildrick »

I went through this entire thread but saw no mention of the condition of the insides of your gas tank.

If you have crud collecting on the screens at the petcock intake, you will get fuel starvation symptoms, especially when the fuel level gets low.
The crud may not be able to pass through to the fuel bowl in the petcock but may be blocking the screen inside the tank just the same.

I went through this with my 64C coupe, and after several failed attempts by radiator shops to clean out the rust and crud and coat the tank inside, I finally got the tank cleaned properly by a Gastank ReNu franchise place.

On my 65 C coupe, when I got similar symptoms (balking with engine not taking throttle), I replaced the tank with a repro from Stoddards.
But this was premature, as the real cause turned out to be a weak fuel pump.
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Heidi Frances
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Re: Diag: Recently running again but having some running iss

#66 Post by Heidi Frances »

Harold,

With the new fuel and timing just so, try to determine if it is rich or lean when it starts to falter under load. Do you hear backfiring out the muffler or do you hear those lean misses the Beetle is so famous for? Also, what do the plugs look like? There might not be enough time for the plugs to tell their story though.

Lean or rich will send you in very different directions. Lean is most likely fuel delivery like a clogged tank filter or weak pump as others have noted. If the pump is getting hot and failing; a bit of cool water on it will clear up the issue for a few minutes and can help point to an overhaul. A rich scenario is more likely electrical with the high voltage side not up to the challenge (coil or condenser). That you can check with a timing gun... Do you see it not flashing consistently at higher revs? You will also get some backfiring with a hot muffler.

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Mervyn Hyde
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Re: Diag: Recently running again but having some running iss

#67 Post by Mervyn Hyde »

Just checking Harold (I know you are a busy guy with the other aspects of life):

1.0 You checked the timing at around 3000 rpm and got around 30 degrees?
2.0 The fuel bowls have around the right (and same each side) levels?
Merv
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Harold Singh
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Re: Diag: Recently running again but having some running iss

#68 Post by Harold Singh »

Dave Wildrick wrote:I went through this entire thread but saw no mention of the condition of the insides of your gas tank.

If you have crud collecting on the screens at the petcock intake, you will get fuel starvation symptoms, especially when the fuel level gets low.
The crud may not be able to pass through to the fuel bowl in the petcock but may be blocking the screen inside the tank just the same.

I went through this with my 64C coupe, and after several failed attempts by radiator shops to clean out the rust and crud and coat the tank inside, I finally got the tank cleaned properly by a Gastank ReNu franchise place.

On my 65 C coupe, when I got similar symptoms (balking with engine not taking throttle), I replaced the tank with a repro from Stoddards.
But this was premature, as the real cause turned out to be a weak fuel pump.
Pumped out all the gas and the petcock screen was clean as it could be with no crud. Nothing in the fuel and blew out the lines.
Harold
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1964 356C Irish Green
1995 993 GP White

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Harold Singh
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Re: Diag: Recently running again but having some running iss

#69 Post by Harold Singh »

Mervyn Hyde wrote:Just checking Harold (I know you are a busy guy with the other aspects of life):

1.0 You checked the timing at around 3000 rpm and got around 30 degrees?
2.0 The fuel bowls have around the right (and same each side) levels?
Yes 30 deg mark was right on at 3k rpm. I have rpms on my light. Used a different color for the 30 deg versus the tdc and 5 btc.

Fuel bowls were not checked.
Harold
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Harold Singh
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Re: Diag: Recently running again but having some running iss

#70 Post by Harold Singh »

So just FYI folks, out of frustration I bought a rebuilt big bore engine with rebuilt Solex carbs, distributor, generator etc.

At this point, I was told the baseline was not set on the carbs so, I’ve asked a friend to help me do that on this new engine. Honestly, it didn’t turn out to be as plug and play as I hoped with only fine tuning but, I think it will be better and I can hopefully get some driving in before it snows. I couldn’t stand to lose the whole driving season.

This will end the diag thread and the solution was the nuclear option. Replace it all.
Harold
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Mervyn Hyde
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Re: Diag: Recently running again but having some running iss

#71 Post by Mervyn Hyde »

A shame Harold, as it was getting down to a very few items it could actually be (esp., fuel delivery). Good luck with the new motor before winter drops in. We are spoiled here with 12 months of motoring.
Merv
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