Scout will idle but dies when put into gear

[dltaylor617]

I got my 1978 Scout II 345 about 4 months ago after it sat in storage since 1993. I replaced the gas tank, spark plugs, most vacuum lines, fuel filter, and the carburetor, Holley 2210, has been rebuilt. I can start up and idle fine, but when I try to shift into drive or reverse, the engine dies. After it warms up it runs even worse. I dont know where else to look

 

[Scoutboy74]

Hey, you made it! Glad to see you found your way here. When your engine is idling in p or n, there is little to no load on the engine. Placing it in gear obviously introduces a load where none was previously present. The fact that it runs worse once the engine warms indicates that the choke plate May not be opening fully. Choke plate should close for a cold engine and then gradually open as the engine warms.
Now, let's discuss that large vacuum port on the front of the carb. Is that normally connected to something or is it always open to the atmosphere as seen in the pics? When you replaced the spark plugs, did you do them one at a time or all at once? I suggest double-checking your plug wire routing to make sure all wires are going to their correct locations on the distributor cap as per the engine firing order and that they are securely connected on both ends. Its easy to get a wire or two crossed up or left loose. Did you set the spark plug gap correctly? Which brand/model of plugs did you install? Do you have a vacuum gauge? If not, you should get one. Its an inexpensive and valuable diagnostic tool for dealing with these ancient rust piles. Your vacuum reading at idle will tell us a lot about what your engine is up to. Did you mess with the timing/distributor position at all? Get used to be peppered with questions any time you post on question on these forums. Your ability to answer them will be the difference in whether or not this issue gets resolved. Try not to hit them all, even if you don't know the answer. Its okay to not have an answer to a question. Ignoring or blowing off a question isn't okay.

 

[dltaylor617]

Tge vacuum lin I think you are talking about I connect to the breather.the choke plate will open fully when warm and the choke pull off seems to function as well. Spark plugs were done one by one. And I learned the distrubtor was loise and would move by hand when I tried to replace the vacuum advance line. I will have to check the spark plugs. I do have a vacuum gauge and last I checked it was between 12 ro 15 on a rough idle.

 

[Scoutboy74]

Let's get a fresh vacuum reading at idle making note of gauge needle behavior, ie steady versus erratic. If your manifold vacuum at idle is truly that low, you've got a leak somewhere, or you're living above 10,000 feet elevation, or somebody stupidly stuck a really lumpy camshaft in that slow-winding dump truck motor hoping that would magically turn it into hi-po road ripper. Monkeys would sooner fly out of their arse. I don't think that last one is real likely. Just tossing it out there in the interest of being thorough. A vacuum leak will certainly produce the symptoms you're experiencing. At lower elevations, you should expect to see a steady 18-21 inches hg at idle out of a healthy engine with no vac leaks.
With the distributor lock down bolt being loose, who knows how much movement occurred prior to your ownership and then once you took over. Have you got a timing light? If so, I'd like to have you see where the static timing is at idle. IH sv8 engines time off cylinder #8 not #1 as with most other makes. That little detail catches many an IH newbie off guard at first. Disconnect and plug your vacuum advance line at the distributor for timing. Your engine idle speed needs to be as slow as possible also to avoid influence from the mechanical advance.

 

[dltaylor617]

Updated vacuum reading it 15 to 16, not really erratic but it fluctuates back and fourth at about 1000 rmp, I know it's kind of high but much lower and it will die.

Also the new plugs are acdelco r43

I also put it in reverse after I got the new reading and it did stall out still.

So I plan on the last 2 vacuum lines to to be changed and I was thinking if that didn't help intake manifold gaskets?

I have included a picture of the onlyold lines left on it, simply because I did not get enough line that day

I will have to see if I can get a hold of a timing light

 

[Scoutboy74]

The higher engine speed will influence vacuum reading a little. Peak vacuum is generally seen at a true curb idle speed well below 1000 rpms. You can take some carb cleaner spray...not starting fluid...its too volatile, and spritz around your vacuum lines and the base of the carb. If the rpms increase slightly and the engine smooths out briefly, you just found a vacuum leak where you sprayed. Keep in mind that any mist that gets sucked into the carb will produce the same (false) result, so take care not to spray directly near the top of the carb. Another thing you can try is to partially restrict air flow through the carb airhorn with your hand. If the engine smooths out with less air/more fuel, its just another sign that the air/fuel ratio is incorrect. You don't want to hear this, but I've seen these symptoms be caused by a poor job on the carb rebuild and/or one or more incorrect gaskets used in the carb. This can create an internal vacuum leak. I'm not saying that is the case, just that it is another possibility to consider. Is this truck a roller? I mean, could it move if the engine wouldn't die? The brake shoes aren't seized to the drums preventing rotation are they?

 

[dltaylor617]

Yes it will drive, I replaced those two vacuum lines today and it did better at not stalling and was able to turn the idea down to 800 and got 15 on the vaccum gauge. It ran good until it started to warm I think, but the choke plate moves freely and does open when warm. I was able to drive it around the block but on the way back had to shift to neutral and feather the gas to keep it up.

 

[Mark Pietz]

When I read this, the first thing that popped into my mind was power brake booster. I'm surprised this wasn't the first thing mentioned.

with engine warmed up, clamp off the power brake booster hose, apply the brake (parking brake released, of course) and then put it into drive. If it doesn't die and seems to act normally, then there's your main culprit. Of course, with old trucks like these, there are many culprits lurking in rubber lines, shrunken gaskets, etc. But a bad booster will kill your idle under these conditions. Btdt. Twice.

 

[FDChappie]

If the choke seems to "float", what condition is the bi-metal spring in? The little metal box on the intake houses the spring. It should snap closed when cold and hold the choke open when hot. A broken spring will do what you describe.

 

[Scoutboy74]

when I read this, the first thing that popped into my mind was power brake booster. I'm surprised this wasn't the first thing mentioned.

with engine warmed up, clamp off the power brake booster hose, apply the brake (parking brake released, of course) and then put it into drive. If it doesn't die and seems to act normally, then there's your main culprit. Of course, with old trucks like these, there are many culprits lurking in rubber lines, shrunken gaskets, etc. But a bad booster will kill your idle under these conditions. Btdt. Twice.

Valid point and so easy to check. I know I've suggested this very thing to other forum members in the past and even routinely check for it myself when I'm dealing with a suspect vacuum leak. Sometimes the brain just farts over the simple stuff even when one knows better. Good on ya, Mark!

 

[dltaylor617]

Ok guys, I'm at a loss. I did try the brake booster check and it died the same connected or clamped. I cannot get the idle down now as it keeps stalling out. I have blocked off most all vacuum ports except to distributor advance, pcv, brake booster. I can screw the air mixture screws in all the way and it has no effect. I'm not sure what else to test or check. Should I just look for a new carb?

 

[Scoutboy74]

Having not found an obvious vacuum leak outside of the carb, and with the mixture screws not having any effect on the issue, I think its reasonable to suspect the carb itself is the vacuum leak.

 

[Mark Pietz]

How about now considering a leak in/around the intake manifold?

 

[dltaylor617]

Not sure where I left off I apologize I was away for a while, as I got very discouraged, I put on new intake gaskets, torqued to spec, no effect. I believe the power valve in carb is shot. Since I cannot find one I plan to order a new carb, where is the best place to get one; as I work in law enforcement and my wife is an unemployed nursing student we have a tight budget. Also, should I get the 2210 model that is on it or upgrade to the 2300 or something different.

 

[Scoutboy74]

The 2210 is not real user friendly. If you're considering replacement I'd not go with the same model. Make a clean break. The Holley 2300 list 0-7448 in 350 cfm is a good option. It can be set up and purchased right here from IH parts.

 

[FDChappie]

Most auto parts stores stock a few Holley power valves. Or order from summit racing.

 

[dltaylor617]

Well gentlemen I have an update, my Holley 2330 4412s came in Sunday and I got it put on and now she runs like a dream. I'm guessing all the problems were from a blown power valve that I couldn't find a replacement for. Took her on the first cruise today and she was turning the head to say the least. Thanks everyone who gave input.