Hesitation when accelerating
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Hesitation when accelerating
Hi Guys:
I continue to have a slight delay or hesitation when I accelerate under load. I've adjusted my 2v carb (2100) using my vacuum gauge and feel it is about as tuned as I can. I installed the new carb within the last 18 months. I find no vacuum leaks anywhere. I've replaced the fuel and air filters. I've put in new plugs and wires. I don't hear a miss at idle and once it comes out of the delay (when accelerating) it runs great.
Just wondering what you might think to check next and in what order?
I continue to have a slight delay or hesitation when I accelerate under load. I've adjusted my 2v carb (2100) using my vacuum gauge and feel it is about as tuned as I can. I installed the new carb within the last 18 months. I find no vacuum leaks anywhere. I've replaced the fuel and air filters. I've put in new plugs and wires. I don't hear a miss at idle and once it comes out of the delay (when accelerating) it runs great.
Just wondering what you might think to check next and in what order?
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Guess that would help. It's a 360FE. It's been a while since I checked timing, but last time I checked it was where it needed to be (around 6*BTC IIRC). All I know is it did not hesitate before. It only started recently (maybe 6 weeks ago or so) and I thought it was just the fuel filter which I replaced.
More Turbo
Joined: May 2014
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From: Lakeside, Arizona
Guess that would help. It's a 360FE. It's been a while since I checked timing, but last time I checked it was where it needed to be (around 6*BTC IIRC). All I know is it did not hesitate before. It only started recently (maybe 6 weeks ago or so) and I thought it was just the fuel filter which I replaced.
Also, what's the condition of the carb? Rebuilt? Gunky? New?
Lead Driver
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I'd check the accelerator pump.
Is your vacuum advance hooked up to manifold or ported ? sometimes if you are hooked to manifold with too low of an initial setting when you open the throttle plates the vacuum drops and thus drops your vac advance out leaving you with dull spot .
Is your vacuum advance hooked up to manifold or ported ? sometimes if you are hooked to manifold with too low of an initial setting when you open the throttle plates the vacuum drops and thus drops your vac advance out leaving you with dull spot .
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Hmm, good point. I have vacuum advance running to the lower port on the left side of the carb below the choke housing. I believe that port is manifold vacuum (below throttle plates) but I'm not 100% sure. I've seen some posts where any port in the carb is ported vacuum. So, if I'm wrong, then I am connected to ported vacuum.
Can you shed any light on whether I'm correct or not?
Can you shed any light on whether I'm correct or not?
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More Turbo
Joined: May 2014
Posts: 665
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From: Lakeside, Arizona
Hmm, good point. I have vacuum advance running to the lower port on the left side of the carb below the choke housing. I believe that port is manifold vacuum (below throttle plates) but I'm not 100% sure. I've seen some posts where any port in the carb is ported vacuum. So, if I'm wrong, then I am connected to ported vacuum.
Can you shed any light on whether I'm correct or not?
Can you shed any light on whether I'm correct or not?
Can see it in the left side, just above the front mount hole. That is the ported vac for the advance.
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Lead Driver
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Ported comes off above the plates.
Manifold vacuum is fine if you tune for it but for most applications ported is not only what it was intended to use but it's just easier to tune for. you could try it on ported and if it doesn't help I'd look at the accelerator pump.
Manifold vacuum is fine if you tune for it but for most applications ported is not only what it was intended to use but it's just easier to tune for. you could try it on ported and if it doesn't help I'd look at the accelerator pump.
More Turbo
Joined: May 2014
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From: Lakeside, Arizona
Ported comes off above the plates.
Manifold vacuum is fine if you tune for it but for most applications ported is not only what it was intended to use but it's just easier to tune for. you could try it on ported and if it doesn't help I'd look at the accelerator pump.
Manifold vacuum is fine if you tune for it but for most applications ported is not only what it was intended to use but it's just easier to tune for. you could try it on ported and if it doesn't help I'd look at the accelerator pump.
Only thing I would say again is to double check timing. Retarded timing will cause some hesitation, and if possible ya might bump it up a couple degrees to 8*.
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Yes, great advice on here! Thanks guys. Yes, advance is ported on that left side in front and below choke housing. It sounds like I might have a timing issue. I'll definitely check it and maybe put it at 8* to see if it makes a difference. Maybe in all my tuning, adjusting, and replacing I may need to adjust timing again...
Lead Driver
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You should have at least 8 ,on most engines more than that. but what really matters it your mechanical all in, see what that is at 2500 and that will tell you if you can add more initial without causing problems.
as far as initial goes as long as it doesn't kick the starter when you crank it you're not going to hurt anything.
as far as initial goes as long as it doesn't kick the starter when you crank it you're not going to hurt anything.
Lead Driver
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From: San Jose, CA
As was mentioned, another easy check is to look down the carb while you roll the throttle lever back and watch for a nice healthy jet of fuel squirting into the carb throat.
Since you did not find any vacuum leaks, but an over-lean condition is indicated by the bogging, this would be a good easy first step. Even new carbs get clogged up and fail.
Especially modern ones!
Paul
Since you did not find any vacuum leaks, but an over-lean condition is indicated by the bogging, this would be a good easy first step. Even new carbs get clogged up and fail.
Especially modern ones!
Paul
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