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Posted by: BENBRO02 Jun 18 2018, 10:45 AM

I finally got my 914 on the road but switched to carbs to save money. The car runs rich. I have heard that the stock cam is not the perfect profile for carbs and also that the car needs to be run slightly rich to keep the engine temperature down. I have never adjusted a carb before and was wondering if I should try to lean the mixture myself or if this is better left to an expert. I recall that if an engine runs lean bad things can happen to pistons and valves.

Posted by: ConeDodger Jun 18 2018, 10:49 AM

Are there any old VW shops in town? There’s a process and a learning curve. From the words in your post, I’d say you’d be better off leaving this to a pro...

Posted by: BENBRO02 Jun 18 2018, 10:58 AM

I feel like my mechanic is very knowledgeable. He put the carbs on initially and has made one adjustment since. I'm just wondering if it's as good as it gets with the stock cam? You can smell the rich mixture when the engine is running. I guess I'll talk to him. Thanks

Posted by: McMark Jun 18 2018, 11:37 AM

The cam will work fine, but is pretty mild. So a different cam, in the same engine, would make more power. But the stock cam is not a problem.

You need the following to find success:
1. A GOOD linkage (http://www2.cip1.com/ProductDetails.asp?ProductCode=C31%2D129%2D941%2D400). None of the cross-bar linkages are good.
2. All four throats must be synchronized correctly, both at idle and off-idle.
3. The venturi must be sized correctly which depends on which carbs you have and the size of the engine.
4. The idle/main/air jets must all be sized correctly.
5. The floats must be set correctly.
6. The accelerator pumps must have matching delivery rates.
7. The ignition timing must be correct (123Ignition Bluetooth Tunable Distributor).

If your mechanic doesn't talk about ALL of these things, he may not be the right person for the job. Correctly tuned, the carbs should give nice smooth engine performance. I see a lot of carb engines come through my door, and a lot of those were worked on by other shops that didn't really know what they were doing.

Carbs are becoming a bit of a lost art for mechanics. I've spent an absurd about of time learning and understanding how they work and how to tune them. Any 'normal' repair shop isn't going to invest that kind of time for a small percentage of their customers.

The ideal answer is to learn how to do things yourself -- at least the basics. Carbs take pretty regular tweaking and tuning. They're NOT set it up once and you're done. So you either need a shop that knows what they're doing, or you need to start learning.

I cover a few aspects in this video.

https://www.youtube.com/watch?v=ZS3oNSwkUPk

Posted by: ConeDodger Jun 18 2018, 11:55 AM

^^^
These steps. And McMark is right, lost art. That’s why I suggested a VW shop.

The steps must be done in order too...

Posted by: BENBRO02 Jun 18 2018, 12:50 PM

Thank you!

Posted by: rjames Jun 18 2018, 12:55 PM

What was wrong with the original FI?

Posted by: 914_teener Jun 18 2018, 02:18 PM

The mechanic didn.t know how to work on that one either.

Posted by: ClayPerrine Jun 18 2018, 05:56 PM

You need a different mechanic.

The stock FI will work far better than carbs on a stock engine. Better gas mileage too.

Posted by: Jeff Bowlsby Jun 18 2018, 06:12 PM

And once you pay a mechanic to fiddle with the carbs...the FI will be less expensive overall. Sell the carbs, put the FI back on. You can do this yourself...its not that hard.

Posted by: BENBRO02 Jun 18 2018, 06:48 PM

I don't know what was wrong with the fuel injection but I was tired of getting ripped off and still having a non-running car. My new mechanic said it would be cheaper to go with carbs including labor and I would be driving the car sooner. I have driven the car about 1,000 miles in the first month. He gave me the choice and I picked the carbs. I did save the fuel injection parts and may go back eventually but I'm having fun driving it now even with the rich condition. Rich running carbs are more fun than non-running injection.

Posted by: rhodyguy Jun 18 2018, 07:24 PM

Buy yourself a copy of the Weber tech manual from CBperformance. Ljet wouldn't idle for you?

Posted by: BENBRO02 Jun 18 2018, 07:36 PM

It wouldn't idle and would miss badly and then it was ok for 2 minutes and there it goes again. It was missing so much that gas was in the crankcase.

Posted by: The Cabinetmaker Jun 18 2018, 07:40 PM

"Rich running carbs are more fun than non-running injection."

Not when the excess gas washes out your cylinders and ruins your rings. Running rich is not good for our engines. I don't care about about your choice of induction system. Fix the rich

Posted by: SirAndy Jun 18 2018, 08:13 PM

https://en.wikipedia.org/wiki/Eat_the_Rich_(film)

Posted by: Dave_Darling Jun 18 2018, 09:25 PM

How about this one?


https://www.youtube.com/watch?v=0LZxelSc62Y




I wonder what the OP's fuel pressure is? Using the FI fuel pump usually leads to a stupefyingly-rich mix....

--DD

Posted by: SirAndy Jun 18 2018, 09:36 PM

Lemmy is also in the movie ...

Posted by: BENBRO02 Jun 19 2018, 08:26 AM

That could be it, I'll check with my mechanic. Thanks

Posted by: Philip W. Jun 19 2018, 09:37 AM

I agree- absolutely - my bet is your mechanic didn't know the bosch FI and wasn't willing to learn so he THOUGHT he knew carbs( but maybe not the intricacy related to a flat 4 vw/Porsche motor) - so everything mark said earlier here and Jeff B and many others will tell you MPG and performance you are way ahead with FI... -
I bought my car not running- the guy said he tried to work on it but could not get it running and was going to put carbs on it because he said it was"easier" - which I doubted from the start, as I had a 69 Austin healy with dual webbers 30 years ago and that was a bitch to keep tuned and running ugh!! SO all I did was dig into the FI d-jet stuff here on this site, and one week into owning my car I had a new rebuilt MPS , cleaned the tank lines injectors etc and car fired right up!! it was not that hard!! - from there fine tuning and a few vacuum leaks but car purrs like a kitten- I get over 30 mpg on highway- that is 10 years of pain free driving a car since no retuning carbs, cleaning out idle jets bla bla bla -- eat, drink, drive, fun! L-jet may be even better than d-jet as long as you have a properly functioning air flow meter. The ECU's are almost indestructible and rarely fail.
- Find a member near you to come over and get you going- you can do this yourself if you want.
Good luck - I hope you see this is just encouragement, not trying to give you a hard time, but just good advice based on experience.

Phil

Posted by: The Cabinetmaker Jun 19 2018, 10:01 AM

^ best advice on this thread.

Posted by: 914_teener Jun 19 2018, 10:04 AM

Why ask your mechanic?

Why triangulation?

Why not just get your mechanic to get on this forum and learn something himself.

Better yet....hang out here and learn yourself.

I just don't get triangulation posts like this. Isn't becoming part of a learning community what this forum is about?

The German engineers spent hours working on the setup for the motor. L-jet can be tuned to run way better than carbs.....given that you learn how it runs.

Rant over......carry on.

Posted by: rhodyguy Jun 19 2018, 01:54 PM

In all likelihood, you had a vacuum leak someplace in the Ljet system resulting in the low idle. There are number of spots to suspect. You need to be running a self regulated rotary fuel pump with no more than 3.5# of fuel pressure for the carbs. If you are using a noise making facet style, or FI pump with a cheap FP regulator, you need to ditch that delivery system. Hold on to the FI parts.