Won't Start

ATLvolksfan · Posted: Fri Apr 22, 2011 2:05 pm Post subject: Won't Start

Here are my conditions:

Freshly rebuilt 36hp
It has gas squirting down the carb throat
It has spark at the plugs
point gap is set correctly
Distributor is from a 73 and does not have the vaccuum can installed.

When I crank it over it sprays rhythmically out of the carb and while I was playing with the timing I got it to pretty consistently backfire.

My question is: What does the it mean when it backfires? Is the timing to retarded or too advanced?

Do you have to time the car based on the engine or on the distributor? If it is by the distributor, what is the correct timing for a 73?
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"Come to terms with your Ass, for it bears you." - John Muir

yauchzee · Posted: Fri Apr 22, 2011 2:18 pm Post subject:

009 Distributor? 7.5 degrees btdc to start it, then 28-32 degrees btdc at 3500rpm with a timing light. Make sure your firing order is right...might be why it won't fire up and could explain the backfire.
_________________
Stefan

1972 Super Beetle Convertible

ATLvolksfan · Posted: Fri Apr 22, 2011 4:20 pm Post subject:

It isn't a 009. I don't have it handy right now so I can't give you an exact number. There is just a hole where the vacuum can is supposed to be. It ran with this distributor before it was rebuilt, so I know it will work. I am pretty sure the spark plug wires are in the correct order. Number 1 goes over the notch in the rim of the distributor and they go on counter clockwise, correct. It fires 1-4-3-2?
_________________
"Come to terms with your Ass, for it bears you." - John Muir

ATLvolksfan · Posted: Fri Apr 22, 2011 4:30 pm Post subject:

To be more specific, if I know I have a distributor from a 73, should I time the engine to 5 degrees BTDC, or should I time it to 10 degrees ATDC because my engine is a 1200?
_________________
"Come to terms with your Ass, for it bears you." - John Muir

smkn_vw · Samba Member Joined: August 22, 2004 Posts: 809

Backfiring means it's firing when it shouldn't be firing. Here's a suggestion, pop the valve cover to see #1 intake and exhaust valves. Turn pulley to find compression stroke (TDC when BOTH #1 valves are CLOSED, not every TDC is the same). Look to see where your rotor is pointing and use that position as your starting point for #1 spark plug wire (it doesn't always point to the distributor notch depending on your setup). Connect other wires clockwise as normal firing 4, 3, 2. Time with light as mentioned previously 28-32 degrees btdc at 3500rpm.
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"So didja?" -Bob Hoover

Boom · Posted: Fri Apr 22, 2011 5:21 pm Post subject:

if you are getting back fires it sounds like your plug wires are out of order
its 1 4 3 2 clockwise rotation.
1 and 2 are on the passenger side of the car in that order 1 is closer to the bumper
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67 Chubby White Chic

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dLk

ATLvolksfan · Posted: Fri Apr 22, 2011 5:29 pm Post subject:

So the notch in the distributor rim should point to the rear of the car? Mine points toward number one.
_________________
"Come to terms with your Ass, for it bears you." - John Muir

yauchzee · Posted: Fri Apr 22, 2011 5:40 pm Post subject:

From Gallery:

Image may have been reduced in size. Click image to view fullscreen.

This is how it is most commonly set up. Try hooking it up exactly as shown and give it a shot. If that does not fix it, then try what smkn_vw is suggesting. Your distributor might be setup backwards, which is not a big deal, but you will need to change your hookup.
_________________
Stefan

1972 Super Beetle Convertible

kokanee · Posted: Fri Apr 22, 2011 5:47 pm Post subject:

Was the distributor gear installed wrong is the back fire coming from the carb or muffler

ATLvolksfan · Posted: Fri Apr 22, 2011 5:54 pm Post subject:

ATLvolksfan · Posted: Fri Apr 22, 2011 5:56 pm Post subject:

kokanee · Posted: Fri Apr 22, 2011 5:57 pm Post subject:

try puting the wires on the way they aer in the pic you have them on wrong

kokanee · Posted: Fri Apr 22, 2011 5:59 pm Post subject:

It will fit in all the way if its in wrong but be 180 out of time I have done this thats way I asked

yauchzee · Posted: Fri Apr 22, 2011 6:07 pm Post subject:

I would line the notch up with the #1 in the image and then turn the crank until your rotor is pointing at the notch. Verify on your valve that you are indeed pointed at #1. If so, then put your cap on the distributor and hook up the wires exactly like in the image. Once this is done, then set your timing per spec. I am guessing with your notch pointed in the direction it currently is and your wires hooked up, you will fix it. If not, then post back and let us know.
_________________
Stefan

1972 Super Beetle Convertible

Boom · Posted: Fri Apr 22, 2011 6:19 pm Post subject:

oops damn I totally fed that up sorry I was typing and watching tv guess I got mixed up sorry
_________________
Ovals are Overrated.....Click to view image

67 Chubby White Chic

Düg Büg

dLk

yauchzee · Posted: Fri Apr 22, 2011 6:24 pm Post subject:

@boom: Did you? I looked at your last post and I think you got it right, but I am eating, drinking a beer and watching tv now too!
_________________
Stefan

1972 Super Beetle Convertible

ATLvolksfan · Posted: Sat Apr 23, 2011 6:25 pm Post subject: NOW RUNNING!!!

I'm still not sure what exactly i was doing wrong in the first place, but I kept changing the spark plugs wires around, and I finally got a result. This is the first run of my engine!!! The video below was right after I ran it in. It has an exhaust leak, and it needs the valves adjusted, but damn if it doesn't run like a maniac!!!! I'm so happy right now!!!!

Link

_________________
"Come to terms with your Ass, for it bears you." - John Muir

ATLvolksfan · Posted: Sat Apr 23, 2011 7:01 pm Post subject:

So I'm curious. After I switched the wires around, they are different from the diagram above. My number one wire is where number 4 is in the picture and my number three lines up with the notch. Does this mean that my distributor gear is in backwards? It runs, so I'm happy, but I don't like that it is strangely configured.
_________________
"Come to terms with your Ass, for it bears you." - John Muir

yauchzee · Posted: Sat Apr 23, 2011 8:04 pm Post subject:

Backwards would be:

Oh, and you are going to be told a million times to get the fuel filter out of the engine bay and to install it either under the gas tank or under the car by the transmission. Smile

Way to get it running!
_________________
Stefan

1972 Super Beetle Convertible

ATLvolksfan · Posted: Sat Apr 23, 2011 10:20 pm Post subject:


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