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| Carb lube? Choke problem https://slantsix.org/forum/viewtopic.php?t=32929 |
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| Author: | kafer65 [ Mon Dec 22, 2008 8:00 am ] |
| Post subject: | Carb lube? Choke problem |
On cold startup my engine begins to load up badly. Its way rich and does foul the plugs out if left at an idle too long if it doesn't stall outright. After it warms up it runs great. The throttle is NOT returning completely every time which also effects the warm idle speed. Should I lube it with atf to see if it will return better? Its very clean otherwise. It does seem to run better cold if I push the butterfly more closed. Is this a choke stove tension adjustment or a do I need to pinch the the doohickey a little narrower? This is a holley 1920. I'm still unsure what to do after reading the choke instructions. ________ mary jane |
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| Author: | Reed [ Mon Dec 22, 2008 8:34 am ] |
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Closing the choke will make it run richer. You say that the carb "loads up" which I interpret to mean "runs rich." If the carb is running too rich cold, then you want the choke valve tio be more open than closed. (1) make sure the choke pulloff diaphragm is functioning. These can go bad and not hold a vacuum. As soon as the motor starts, the choke plate should be pulled open roughly 1/4 inch by the pulloff diaphragm. If it doesn't, then your diaphragm is blown or the linake is misadjusted. (2) If the diaphragm holds a vacuum, then double check the choke pulloff setting. Again, as soon as the diaphragm sees vaccum, the choke buterfly should open up about 1/4 inch. (3) if your throttle isn't returning to closed when you let off the pedal, then you need to replace or adjust your throttle return springs on the carb, and/or adjust the throttle cable. I have seen (and done myself) throttle cables which were misadjusted and wouldn't allow the carb to fully close the throttle plates. It is a simple adjsutment of the hold-down bolt on the sleeve. Loosen nut, adjust, tighten nut. |
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| Author: | SlantSixDan [ Mon Dec 22, 2008 9:20 am ] |
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The choke pull-off adjustment is critical to proper carburetor operation. "About a quarter inch" is a good starting point, but that's all it is; adjusting exactly to spec is the best method, but if you won't do that, then be prepared to adjust it in small increments (via the U-bend in the link) until you get it right. Of course the choke thermostat must also function correctly, be adjusted correctly, and the choke pushrod mustn't be bent or otherwise brutalised. Here's another pointer to the electric choke kits. Do not lubricate the linkages at any point. They are meant to run dry; any lubricant will collect dirt and they'll stick again sooner and worse. Throttle cable or torque rod adjustment is crucial, as Reed says. So is proper throttle return spring tension; the spring can take a set after a lot of years and fail to pull the throttle closed again. A too-long or too-weak replacement spring will have the same effect. Here is the Holley 1920 operation and repair manual (pdf). |
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| Author: | kafer65 [ Mon Dec 22, 2008 11:42 am ] |
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What I said before was wrong. If I open the butterfly it runs better. The idle comes up and the engine isn't loading up as much. Vacuum can is pulling and holding it just isn't enough to get the butterfly open where it seems to run best. Even if I were to squeeze the tang all the way together I don't think it would be enouhg. If I shorten up the stove linkage that would do it but I'm wondering if that will mess something up once it get warmed up. ________ vaporizer volcano |
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| Author: | Reed [ Mon Dec 22, 2008 6:28 pm ] |
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Read the manual Dan provided and adjust your carb accordingly. |
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| Author: | Rug_Trucker [ Tue Dec 23, 2008 9:21 am ] |
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'nuther TN slanter! Where you from? |
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| Author: | kafer65 [ Mon Dec 29, 2008 1:46 pm ] |
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I'm in Cookeville. Tried pinching down the tang a couple times and it worked. Its not loading up any more at idle. Much, much better. ________ BMW 2002TII |
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| Author: | Rug_Trucker [ Mon Dec 29, 2008 8:22 pm ] |
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I am about 110 miles West of you near Dickson. |
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