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Dirtyowlnumber4

throttle hesitation

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The engine will hesitate a lot if throttle is applied too quickly. It will die sometimes as well if i depress it too much from idle. It likes to run about 30-35 degrees advanced as well which seems a little odd. anything less than that and it gets worse, still not good where it is though either. Cant start on hills or anything.

 

These are the speculations I have:

 

-Carb adjustment might be off, all I know to adjust is the idle mixture and that doesn't make a difference.

 

-Vaccuum issue possibly, cant find any leaks around the carb though.

 

-Not enough spark maybe, but entire ignition system is new, EI, no ballast.

 

The car is going to be used for racing so I would like to get the throttle response pretty good.

 

A14 weber 32/36

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In a strictly race configuration, high speeds engine never below 4-6K the mechanical advance can be locked and the timing set to 30-35 total advance. If driving on the street this is not wise as the engine will not run well below wide open throttle and will benefit from vacuum and mechanical advance. So driven as a street car or full race????? Or both????

 

 

Again if primarily used for racing you are only going to need good throttle response from a stop.... which only happens at the start of the race.  

 

 

Sounds like the accelerator pump is not working well.

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Did u check jets make sure its for that engine. Call pierce manifold, Gilroy, ca.

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The engine will hesitate a lot if throttle is applied too quickly. It will die sometimes as well if i depress it too much from idle. It likes to run about 30-35 degrees advanced as well which seems a little odd. anything less than that and it gets worse, still not good where it is though either. Cant start on hills or anything.

 

These are the speculations I have:

 

-Carb adjustment might be off, all I know to adjust is the idle mixture and that doesn't make a difference.

 

-Vaccuum issue possibly, cant find any leaks around the carb though.

 

-Not enough spark maybe, but entire ignition system is new, EI, no ballast.

 

The car is going to be used for racing so I would like to get the throttle response pretty good.

 

A14 weber 32/36

 

 

I hope your timing is 30-35*BTDC is at 2,800 RPM and not idle.  As Mike pointed out, check the accelerator pump discharge.  Disconnect and plug the vacc adv vacc line. sometimes the vacc adv unit diaphragm is cracked and there is a vacuum leak there.

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It is 30-35 degrees at idle. It is going to be primarily a race car but it will probably be driving itself to events.

 

Accelerator pump is one of the first things I thought of. My beetle was just having this problem and adjusting the accelerator pump fixed it right up. But on this weber there appears to be no way to adjust it. I've taken it apart and it looks fine inside.

 

racerx someone suggested  that I should use high altitude jets

 

just put in some platinum plugs didnt change

 

I made a little video here showing what its doing if that helps.

 

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Something in the method is wrong. 30 degrees probably wouldn't even start, let alone idle. Check the pulley notch and timing scale. Should be about 1/3 that amount.

 

High altitude jets are leaner. I don't think you need leaner but check your plugs they can be read and indicate what the fuel air mix is like. Take for a twenty minute drive and pull over and remove them and look. Tan light brown is good, dark or black is way too rich, lighter is lean, white is dangerously lean. Post picture of the plugs.

 

Sounds like accelerator pump not giving enough. Shut off and look down the carb while you open the throttle. You should see a strong squirt of fuel into the primary side. The weber has a diaphragm on the side that supplies the squirt of fuel.

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That's one drawback to the weber... you have to drive it. Step into it half way then squeeze it the rest as it revs up. Takes some practice but easy to learn where it runs best.

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Yup, can't floor it off the line or it bogs.

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Yeah once its above 2k rpm it is excellent. As long as the bogging is normal I don't mind it, Just need to fix my handbrake so I can start on hills hoho.

 

I tried to take a video of the fuel squirting out of the carb but you couldn't really see anything. Anyone know of a video they could link me that shows what might constitute a strong squirt of gas?

 

Here are the plugs

 

nTBpx5b.jpg?1

 

Let me make sure I'm doing the timing right:

 

When the timing light says 30, the notch is at 0. Maybe they're both supposed to be at 15, in which case the timing is 15 degrees, not 30. Otherwise I'm not sure why its running at 30.

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/\...huh? What's ur base timing?

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/\...huh? What's ur base timing?

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when I've got the timing light at 0 the notch is off the scale. where 30 would be. Im going to look tomorrow my pulleys kind of dinged up maybe I'm looking at the wrong spot.

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Notch should be lit up by the flash when it's around 10 degrees or what ever the A series is supposed to be set at.

 

Yes set engine to TDC by hand by watching piston through the plug hole or use a drinking straw to show when the piston is at the top.... then check the 0 on the timing scale for the mark on the pulley.

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Mark Tec with chalk or somtin, makes it easier

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Meant tdc.

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When the timing light says 30, the notch is at 0. Maybe they're both supposed to be at 15, in which case the timing is 15 degrees, not 30. Otherwise I'm not sure why its running at 30.

 

If timing light has a degree setting that is usually to check full advance....

If your gun is set for 30 and it reads on the zero mark then your timing is infact 30....

 

You can use it to set the base timing but

Make sure you verify that the zero mark you see is infact tdc...

Then whatever is set on the gun is your timing... as others have said you need to be around 10 or so...

 

So set for 10 and adjust to the zero mark.... same works for full advance, if you set the gun to 30 and bring the motor rpms up you should again be around the zero mark... adjust gun till it reads the zero and that's your full advance...

 

With that said.... you say your at 30 degrees at idle now to make it run... how high does the advance read when you increase your rpms?

 

I've seen usually a 20 degreee increase with the timing numbers

So if idle timing is 10 that becomes 30 at full advance... if your starting at 30 already your full advance could be around 50. Thats seems quite high...

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WTF is this a normal timming light? Not the dial type

 

simple put light at crank and run at idle and see what it says. it sould be near say 8-12degs.

 

a weber DGV just bought  on a A14 might be a little big for this motor but manageable and yes hard getting started on a HILL. I had same proplem with a 38/38 weber on hills. Loose vacuum as both barrels open up at same time

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This.

 

Idle must be set to factory specs (650-750?) or mechanical advance may be present and throw it off. If factory carb the vacuum advance will also be negative but who knows where vacuum advance 'comes in' on a weber... better disconnect the hose.

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What kind of timing light do you have? Does it have a dial, where degrees can be adjusted, usually the dial is located at the back of light. Or do you have a digital timing light? 2nd, do you know where your timing tab or pointer is at? 3rd, do you know where ur tdc or zero degrees is at?

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a weber DGV just bought  on a A14 might be a little big for this motor but manageable

Absolutely not. The A12 I had in my 320 would actually pull the secondaries open almost by itself. It was weird to feel that under foot.

 

One thing to consider is the age of the Weber. About 12-15 years ago Weber did a redesign of the main fuel circuits. In the older style carb, the primary and secondary shared a fuel circuit, which meant that when you romped on the throttle and the secondaries opened, it would take a second for the secondary fuel circuit to react to the sudden fuel demands. The newer style carb (marked with a 5A) has split individual circuits, alleviating this problem and eliminating the lag.

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It is 30-35 degrees at idle. It is going to be primarily a race car but it will probably be driving itself to events.

 

Accelerator pump is one of the first things I thought of. My beetle was just having this problem and adjusting the accelerator pump fixed it right up. But on this weber there appears to be no way to adjust it. I've taken it apart and it looks fine inside.

 

racerx someone suggested  that I should use high altitude jets

It sounds like this is your first foray into racing. You've got a steep learning curve in front of you. First thing you need to learn is how to observe your car and recognize when there's a problem. The timing sounds like one of those problems.

 

The second thing you are going to need to learn is how to jet your carb. Every track is different, every day is different.

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I have a digital timing light. I checked out the notch today, it is in the right place, the cylinder was at the top when it was, I marked it with spraypaint. 

 

You can barely see the timing mark here, but its there. I guess my timing light must be broken. The cars running good, I'll take it down to the shop and have them put their light on it.

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Sounds like u also need valve adjustment...good to hear you got your timing figure out.

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