Well, after 4k in one month, my motor started acting up. The idle started to become rough, hot or cold, it didn't matter. Decided to finally swap out all the vacuum lines which all looked to be original. In doing so, I found the two hoses at the front / center of the carb, just above the two "caps" or "cover" bolts, melted, brittle, therefore clogged. One of the hoses leads to a "T" where one ends goes into what I believe to be the "Throttle Positioner" while the other end fits into a fitting screwed into the intake manifold close to the block. The other hose leads back to the carb off of some small square thingy that screws into the carb. I've since replaced all the hoses, yet, still - rough idle. My throttle plate seems to be stuck open, too. I know, I know....go Weber. I will eventually, but would like to get the stock one going, again, if possible. Anyhow, any feedback as to what the problem might be would be helpful. Thanks in advance.
Well, finally resolved the issue. When I went to replace all the vacuum hoses I found the hose that leads to the Throttle Positioner burnt shut, dry, and brittle with age. It was the original hose. I guess it eventually threw my throttle position out of whack when vacuum could no longer pass threw. The throttle plate seemed to be stuck and wouldn't close all the way. Basically just studied how it all mechanically worked together and traced down the linkage to a screw in the backside of the carburetor. 3/4 of a turn clockwise....and she was back to purrrrring like her old self. I think the timing should be double-checked to get her spot on, but she's actually running so much smoother than she was before the issue. Vacuum lines, vacuum lines, vacuum lines. I always knew the importance of good lines. Swapped them all out on a 79' Pickup I once owned and saw it made a difference BIG TIME. Had plans to change them out on this truck...but I lagged. See what happens when you lag?
LoL. Thanks. Yeah, just trying to get this stock one to pass smog just one more time in it's life. Just one more time. As soon as it does and I get that sticker, that puppy is coming off asap. Gotta go Weber. I got a chance to really go over all the vacuum lines....I mean, really go over them and can see how complex things can get if just one or two lines were to clog up, crack, what have you. PITA! I remember in the 70's how my grandfather would always be b*tching and moaning about the carb, and that was when his truck was only 6-7 years old! Although I gotta tip my hat to the lil complex ****ers....over 30 yrs old, yet still in service.
Expert? By all means, far from it. Allow me to explain. What I initially thought was old vacuum lines throwing my throttle linkage out of whack, actually turned out to be something totally different. First off, and this was a very BIG LESSON for me. Messing with the carburetor settings, especially if you have no experience with these particular carburetors, should absolutely be the LAST THING you should ever do when trying to solve a problem. The absolute last thing. Especially when I'd been driving the truck for 4k miles (one month) pretty much problem free. The carburetor is not just going to re-adjust itself on it's own. Something else had to have been the problem. It turned out that my "half-a**ing" the replacement of the vacuum lines, I missed the one line between the EGR and the carburetor. This particular 2 inch hose had a webbed insulator over the line so there was no way to visually inspect it's condition. So, after replacing 95% of the lines and saw my throttle plate was out of whack, I took 2 cans of carburetor cleaner and went to town on the carburetor, inside and out. It seemed to help with the rough idle. But something still wasn't right. So I messed with the idle screw. That sped the idle up but in reality that only covered the real problem. Because I took it to a friend's shop after hours and hooked it up to his computer which told me my idle was running at 1500! My timing was off by 1-2 degrees, but obviously my idle was way off. Adjusted everything back to where it should be. Needless to say, rough idle returned. This time I went through every single hose, one at a time....and finally got to the hose I did not replace. The one between the EGR and carburetor. Took a razor blade and carefully cut through it to pull it off. Upon close inspection, I found a "slit" or "crack" half the length of the hose on the opposite side of my cut - so in the truck there was no way you could have seen it, especially with the insulation. Replaced it. Problem solved. So my advice to anyone who might think they have a vacuum issue. Take the time to check and double check all your vacuum lines. Check your timing, check for exhaust leaks. Definitely use carburetor fluid and spray it here, there, and everywhere to help you not only clean, but track down any vacuum leaks. The sh*t works. Just take your time. Don't panic (like I did). Whatever you do....DON'T f*%# with the carburetor settings! At least until you've exhausted all other avenues. Expert? Nah. But I am good at admitting when I've fudged up. Learn from my mistake, and YOU will be the expert. Cut I made with a razor blade. You could barely see the "crack" or "slit", so I took a marker to highlight the damage.
After all that....the somewhat smooth idle only lasted a day. On the freeway she'll just purrrrrrr at 80mph. No smoking. No backfiring. But at idle she's a different lady altogether. Replaced all the vac lines. Even pulled the EGR...cleaned her out and replaced it with a new gasket. Idle still irratic. Inspected the plugs. All normal. Constantly checking fluids. All normal there, too. Used another can of carburetor cleaner and this time sprayed it at the outter body of the carburetor. When I hit the backside (throttle linkage side) the idle will rise and smooth out for a beat or two. I'll spray it again, and again, the idle will rise... I now have to believe the stock carburetor needs to be rebuilt. Forget about it. I'm done messing around. Ordered a Weber 32/36 DGEV.
