Won't start

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I drove the Scamp to work today, so I just went outside to check. ;) The puck has a large breather hose to the air cleaner and maybe a 3/8" line to what appears to be a vapor return to the fuel tank. A separate PCV hose, also maybe 3/8", goes from the PCV to the base of the carb. The port next to this is where my distributor advance line is hooked up. Both of these ports face the valve cover. On the opposite side of the carb, there's a blocked off vacuum port.

Thanks for that comment about other manufacturers using manifold vacuum for the vcan. I have a Chevy and was fairly certain that uses manifold vacuum, so that makes sense. That port on my carb next to the PCV connection is ported vacuum (rather than manifold vacuum)? If it's ported vacuum, then it could be 6" at idle, couldn't it, since the throttle was not open? I'm trying to make sense of this, so forgive me if I'm way off.
 
FrozenCaveman said:
I drove the Scamp to work today, so I just went outside to check. ;) The puck has a large breather hose to the air cleaner and maybe a 3/8" line to what appears to be a vapor return to the fuel tank.
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Read about it here.

A separate PCV hose, also maybe 3/8", goes from the PCV to the base of the carb. The port next to this is where my distributor advance line is hooked up.
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That's all correct.

Both of these ports face the valve cover. On the opposite side of the carb, there's a blocked off vacuum port.
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That's suspicious. Show us a pic, please.

port on my carb next to the PCV connection is ported vacuum (rather than manifold vacuum)?
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Correct.

If it's ported vacuum, then it could be 6" at idle, couldn't it
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Yes. That's somewhat of a little more than you'd like to see, though; it suggests your adjustments (base timing, idle speed) might not be set correctly.
 
view_from_valve_cover.jpg
view_towards_valve_cover.jpg
Here are pics of the carb base from a couple different vantage points. Top image is from the perspective of the valve cover. Bottom image shows the blocked off vacuum port on the other side.

The engine idles a bit rough, so I may have a vacuum leak somewhere, but I haven't started trying to isolate it. Oh... While I'm on the topic of potential vacuum leaks, I have a problem with the back top bolt on my intake/exhaust manifold coming loose, and I constantly have to retighten it. It's currently got a white residue around the one bolt hole (coolant?), and I had to replace the gasket a few months ago because it had burned out back there. Seems to diesel when I let that bolt loosen too much.
 
FrozenCaveman said:
The engine idles a bit rough, so I may have a vacuum leak somewhere, but I haven't started trying to isolate it. Oh... While I'm on the topic of potential vacuum leaks, I have a problem with the back top bolt on my intake/exhaust manifold coming loose, and I constantly have to retighten it. It's currently got a white residue around the one bolt hole (coolant?), and I had to replace the gasket a few months ago because it had burned out back there. Seems to diesel when I let that bolt loosen too much.
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Is it a bolt? It should be a stud and nut with a special triangular washer. If it is a bolt, and you're constantly torquing it, it is likely wearing the threads out in the head.

See here: Manifold Mounting
 
Sorry, I thought afterwards that what I said might be misleading. I'm using new studs from when I swapped out the gasket, and a new nut. I reused the existing doughnut washer or whatever it is. The front and back studs use the same doughnut shaped washer. It's a little hard to see in the photo, but that whitish residue is around the stud area.
manifold.jpg

-JP
 
OK, that stud is obviously a mite short....That leak looks more like exhaust leak to me but I am not 100% on that.

I'd also clean up that washer and the flat area on the manifold so they can slip easily and smoothly past each other. (You should be able to see the exhaust actually move it's position at the ends when cold vs. hot.)
 
And on the ported vacuum, whenever I have measured it, it was 0 at curb idle speeds. But that is across a number of carbs, including Holley 4 BBL's so that is a generic number in my head. I may have to go back and check that on my /6's early Holley 1920; you have me curious.
 
The capped off port on the driver side of the carb should have a hose to the input nipple of the thermo sensor on the underside of your air cleaner body.

You've got the wrong nut on that rearmost exhaust manifold stud. See here. The white stuff is coolant, which means you'll need to remove that too-short stud, install the correct stud with the correct sealant on it, then put everything back together. High probability you need to replace the gasket again, too. It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.
 
slantsixdan said:
The capped off port on the driver side of the carb should have a hose to the input nipple of the thermo sensor on the underside of your air cleaner body.

You've got the wrong nut on that rearmost exhaust manifold stud. See here. The white stuff is coolant, which means you'll need to remove that too-short stud, install the correct stud with the correct sealant on it, then put everything back together. High probability you need to replace the gasket again, too. It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.
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Well, a picture does tell a 1000 words. Thanks for catching all that, slantsixdan! Thankfully, the whole process of removing the manifold isn't too bad. Thanks for sourcing those parts! I got these at NAPA. And I'll check to see what, if anything, is connected to the thermo sensor. Since it runs pretty rough when cold, maybe that will help.

Oh, regarding the sealant, all I used was a copper paste. What should I be using?

-JP
 
Loctite № 542 or 592. See here and here.

If you need a new air cleaner thermo sensor because yours doesn't work, send me a PM; I have some new ones.

Rough running when cold: choke problems. Show us another photo, this time of the choke thermostat and pushrod (with air cleaner removed). Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download, and there's a choke adjustment article here; you may well wind up needing replacement parts such as a new choke pull-off and/or put in one of the Electric choke kits.
 
woulnt be first time , see if you didn't knock the wire off the porcelain god damit , check you got spark.

stupid happens too that's wh we gt Fabo family t kik us in the *** and straighten us out lol
gl hope it simple HAGR812 winstoninwisc
 
Not sure if this is the perpective you were looking for, but here's a shot of the top of the carb showing the choke rod.
carb-2.jpg


Nice call on the vacuum line from the carb to the thermo sensor mounted inside the air cleaner - the nipple on the air cleaner side was open. I tested that nipple with a vacuum pump and I'm barely able to get a little bit of vacuum that doesn't hold for long, so I need a new sensor. The air control valve closes if I apply vacuum to it directly, so that still seems to be good.

-JP
 
I've seen choke pushrods goobered up worse than yours; sometimes they're so badly bent and twisted that it's best just to replace. Your bimetallic thermostat spring (inside the box on the manifold) could still be faulty, but maybe not. Here's the problem: to adjust it, you need to remove the box from the manifold, and on a '70-'72 setup like this that means disturbing a gasket junction that's sure to leak on reassembly unless you use a new gasket, and that gasket isn't available any more. So probably best to see if you can get the choke to work correctly by adjusting the pull-off. If not, get a № 1231 Electric choke kit and install that (you'll still have to deal with the gasket junction unless you install a '73-up exhaust manifold, which is the only type presently available new).
 
slantsixdan said:
Here's the problem: to adjust it, you need to remove the box from the manifold, and on a '70-'72 setup like this that means disturbing a gasket junction that's sure to leak on reassembly unless you use a new gasket, and that gasket isn't available any more.
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Not sure what you mean about the gasket - there's an important gasket under where the choke rod assembly connects to the manifold? Is that what you mean by the "box"? I've never tried taking it off, but what purpose does a gasket under there have?

I went ahead and ordered all the recommended nuts and studs (almost $80!) and a new gasket kit. Looking forward to getting it all and making it right. Thanks again!

-JP
 
FrozenCaveman said:
Not sure what you mean about the gasket - there's an important gasket under where the choke rod assembly connects to the manifold?
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Yep. The '70-'72 setup has an open hole at the top of the choke mount. There's a gasket and a stainless steel cup that sits into the open hole, and the choke thermostat mounts atop that cup. The '60-'69 and '73-up manifolds have a closed pocket/cup area as an integral part of the cast iron manifold; no open hole, so no gasket. The original-equipment choke thermostat year groupings in terms of direct interchangeability (fits the manifold and hooks up to the carb) are '60-'61 • '62-'65 • '66-'69 • '70-'72 • '73 • and '74-up (this doesn't mean they're all alike; in most years there was more than one choke thermostat; some of these are functionally interchangeable and others aren't). On the exhaust manifold side, the choke mount is the same for '60-'65, '66-'69, '70-'72, and '73-up.
 
Question about the Loctite 542. It's fairly expensive, and I just wanted to get enough for this job, since it would probably dry out before I needed it again. Is 10ml enough for all 14 head studs?

Thanks,

JP
 
Argh... new RemFlex gasket arrived via UPS nearly bent in half. Poor packaging on the seller's part. Now I need to wait another couple weeks before I get a replacement. :mob: /shakes tiny fist... grumble grumble grumble
 
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