Carb question, need to dump little gas in carb just to get car started |
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Carb question, need to dump little gas in carb just to get car started |
angerosa |
Apr 28 2013, 08:45 AM
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#1
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Member Group: Members Posts: 334 Joined: 21-August 07 From: Reston, VA Member No.: 8,023 Region Association: MidAtlantic Region |
Seems that this year I need to put a little gas into the carb to get the car started initially. I have single Solex carb that no one seems to be able to identify. I'm sure some PO just pulled it off something that was sitting in a junkyard. Once I get car started and it warms up it idles OK but runs rough when you try to drive it. Timing is spot on. Recent (not too many miles ago) tune up with the help of some very knowledgeable 914world brethren. Let’s say it’s a given that there is nothing wrong with the engine. I have an idea of where to go next. I’ve had car for about 7 years. With only what I’ve told you here what’s your opinion?
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ThePaintedMan |
Apr 29 2013, 09:19 PM
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#2
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Advanced Member Group: Members Posts: 3,886 Joined: 6-September 11 From: St. Petersburg, FL Member No.: 13,527 Region Association: South East States |
Assuming it works like every other carb (and physics dictates that it does), you are correct. The accelerator pump should engage with the initial application of the throttle to a mechanically-activated shot of fuel with the in-rush of added air. On some carbs, like the later Webers, this can be adjusted based on how rich the idle circuit already is or how the carb transitions from idles to mains. Every engine "wants" something different. Is there any visible kind of adjustment on that carb, or a reason why it isn't activating with the initial application of throttle?
While you have it out, you might try to carefully remove the accelerator pump cover to inspect the diaphragm. If it's still supple, you could reinstall it and focus on figuring out why the arm isn't actuating the pump itself, and it might be enough to get you to the event you're trying to go to this weekend. However, since you've had the carb on the car for at least 7 years and with modern fuels, I still betcha it's time for rebuild. |
angerosa |
Apr 30 2013, 10:45 AM
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#3
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Member Group: Members Posts: 334 Joined: 21-August 07 From: Reston, VA Member No.: 8,023 Region Association: MidAtlantic Region |
Assuming it works like every other carb (and physics dictates that it does), you are correct. The accelerator pump should engage with the initial application of the throttle to a mechanically-activated shot of fuel with the in-rush of added air. On some carbs, like the later Webers, this can be adjusted based on how rich the idle circuit already is or how the carb transitions from idles to mains. Every engine "wants" something different. Is there any visible kind of adjustment on that carb, or a reason why it isn't activating with the initial application of throttle? While you have it out, you might try to carefully remove the accelerator pump cover to inspect the diaphragm. If it's still supple, you could reinstall it and focus on figuring out why the arm isn't actuating the pump itself, and it might be enough to get you to the event you're trying to go to this weekend. However, since you've had the carb on the car for at least 7 years and with modern fuels, I still betcha it's time for rebuild. So just to confirm... The "at rest" position should be butterfly is closed, accel pump is actuated with the slightest push of the peddle? I noticed that when I had disconnected the fuel line, and took the carb out, I was pressing the actuator arm against the acel pump button and it was spraying a good amount of gas in the barrel... I did it more than a couple of times. Maybe I need to just adjust that cam shaped actuating arm. Possibly it is not tight and got pushed back or I did it a couple years ago without realizing it. That's my exact symptom that if I hit the throttle hard it would stall out. Accelerate slowly and it worked Ok but what fun is that. I think I'll try to adjust it and put it back in just to see. Anyway, rebuild kit is on the way... |
ThePaintedMan |
Apr 30 2013, 10:55 AM
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#4
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Advanced Member Group: Members Posts: 3,886 Joined: 6-September 11 From: St. Petersburg, FL Member No.: 13,527 Region Association: South East States |
So just to confirm... The "at rest" position should be butterfly is closed, accel pump is actuated with the slightest push of the peddle? Correct. QUOTE I noticed that when I had disconnected the fuel line, and took the carb out, I was pressing the actuator arm against the acel pump button and it was spraying a good amount of gas in the barrel... I did it more than a couple of times. Maybe I need to just adjust that cam shaped actuating arm. Possibly it is not tight and got pushed back or I did it a couple years ago without realizing it. That's a good sign. If there is fuel in the bowl and the little plastic nub of the accelerator is depressed, fuel should squirt into the throttle body. So it does look like either the cam or the arm needs some work to actuate the pump. The problem is, I don't know how the cam could have moved. It looks like from the diagram the way it attaches to the throttle shaft is fixed. I.e. it has a slot in it that the throttle shaft can only pass through in one way. It is possible that either the cam or the throttle shaft has somehow become stripped, but we wouldn't be able to see that until you pull the cam off. The other scenario is that somehow the accelerator pump arm is somehow bent. But as Mike said, it's cast aluminum and if it is bent, there's probably little you can do to bend it back without breaking something. Replacing the vaccuum caps is easy - they're just the two rubber black stopper looking things at the bottom of the carb. Autozone/Advance auto sells them in packs of assorted sizes. |
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