Idle Adjusting Screws Missing

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Texas710
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Location: San Antonio, TX

Idle Adjusting Screws Missing

Post by Texas710 »

I have been reading about these trucks idle speed should be set up around 750-850 05 so. My truck starts fine, but was closer to the 500 mark. Once it's warm, it will run, but the gen light comes on and it always seemed slow to me. Now I know why.

I figured it would be an easy adjustment, just tighten a little. Took the engine cover off and I don't see any screws where they are supposed to be. Or am I not looking in the right area. I have a manual, and think I know what to look for.

Is there anything special about these screws? Does someone know the thread pitch and size? Is this something I can pick up at a bolt\screw shop, or is it funky?

I think there are only 2, one for each carb?

Any help would be great.
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pcolette
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Re: Idle Adjusting Screws Missing

Post by pcolette »

I think your carbs use the smaller idle speed adjustment screws (red circle). Both sizes were used for no apparent reason that I've found. And yes, there is one on each carb.
rsz_carb.jpg
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
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pcolette
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Re: Idle Adjusting Screws Missing

Post by pcolette »

Here's a photo of the adjust screw on the front carb.
IMG_3132.jpg
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Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
Texas710
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Location: San Antonio, TX

Re: Idle Adjusting Screws Missing

Post by Texas710 »

Okay, I see. Face palm!

I thought they were lower than that, on the plate that has the two holes...

Sounds like I will be upping the idle and balancing carbs today, or at least attempting...

Thanks as always
Jim LaGuardia
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Re: Idle Adjusting Screws Missing

Post by Jim LaGuardia »

Idle is 850-950 rpm at operating temp.
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Texas710
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Location: San Antonio, TX

Re: Idle Adjusting Screws Missing

Post by Texas710 »

Jim, thanks for the right figures.

I am guessing the truck has an aftermarket tach, and is marked every 500 rpm's. After adjusting, I am now more in that ballpark than I was before and know I am now idling north of 750. This is good. Adjusted by ear/feel first, then the next day took off the cover and used the snail type balance. Was close, but had to tweak it again to get the carbs to match. If I remember the flow was right above 10, about 11 I guess? Is that normal?

I only adjusted the idle adjusting screws, nothing else.

After doing this, I noticed a puddle under the thing, thought it was just water(has been raining), but it was kind of black. Looked around and found my muffler had a hole! Oh well, took up welding last year, best thing I have done lately. Dropping the muffler, welding a patch and putting it all back was not that hard. Had to form the patch around the muffler, I think it has seen its fair share of the Arizona desert and isn't 100% round anymore...

I took the pic before I put a bead on it, only tacked in place in the picture.

Bonus, she runs better with the higher RPM, and no more hole in muffler...
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