the never ending project. 71 super build

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schwim
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Re: the never ending project. 71 super build

I'm not savvy enough to even come up with a useful suggestion. Is this the only carb you've been using or have you swapped in another to check if the issues disappear?
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Super_Randy
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Re: the never ending project. 71 super build

same carb. i bought it used from a reputable source who took it off a perfectly running bus because the owner wanted duel webers. it sat in his shop for a few weeks before he sold it to me. i stuck it on my old engine and it worked fine. no issues. then i found out that engine was shit and the carb sat in my garage for 8 years until i bolted it on this engine. it worked like shit so i threw a rebuild kit at it after completely dismantling it and soaking it in solvent over night. then blasting out every passage i could get to with carb cleaner. put it back together and bolted it back on my new long block.

i don't have another carb to try. i still own the original German carb from my original engine but it's not useable, the air volume control screw snapped off in it (i believe it managed to ether cross thread or get debris in the threads jambing it in there. and me being me i got pissed off and decided oh yeah? let me introduce you to my little friend, Dr. Bigger Screwdriver and snapped the head off) so im kinda screwed unless i want to go buy another carb. which i really don't. cause 1. im cheap. and 2. i really want duel webers (or at least EMPI HPMX's) but as of right now im to lazy to want to hassle with installing an electric fuel pump, fuel pump kill switch (cause you know, i live in CA) and a fuel pressure regulator. not to mention installing, adjusting, and tuning duel carbs.
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Super_Randy
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Re: the never ending project. 71 super build

got pissed this morning and threw my biggest jets in there. 140 main and 60 idle. took some timing out of it (went form 8 down to 5 at idle). still popping out the carb. but not nearly as bad. got it to at least come off idle without popping. then noticed the throttle shaft and nut were wet. sprayed them with carb cleaner. they dried out. played with the shaft, they were wet again. dip my finger in it, give it the smell test. yeap, gas. take the nut and arm off the shaft. wiggle it around, yeap, it has up an down play. put it back together, stripped the threads on the shaft :roll:

so now im thinking, do i bother trying to rebush that one(maybe pull the shaft/bushing out of my German carb? bet they don't fit), or just say the hell with it and buy a cheap carb.



edit:
just ordered a carb from CIP1. it's $90. we'll see what happens. it's got to be better than what iv got right?
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schwim
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Re: the never ending project. 71 super build

Super_Randy wrote: October 28th, 2023, 5:43 pmjust ordered a carb from CIP1. it's $90. we'll see what happens. it's got to be better than what iv got right?
I think it's got to be a huge improvement. I don't remember the guy anymore but years ago paid for the carb guru over on samba to build one. It worked great but I'm sure that wouldn't be the case now :)
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Super_Randy
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Re: the never ending project. 71 super build

well, got the new carb out of the box this morning. blew all the passages out on the carb with carb cleaner. jetted it, 60 idle and 132.5 main (came with a 127 main and 55 idle. and optional 137 main and 60 idle) and it flat out won't start. got the base settings on all the screws. got the fast idle screw set as per every manual in existence and unless you're holding half throttle it wont idle. i cranked it so much i killed the battery. so now that's on the charger.

also noticed the fuel filter was empty this morning. so yeah, i have new problems forming and it's not even driveable :roll:


edit:
well, i got it idling. kinda. at like 400rpm so im back at ground zero! :roll:
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schwim
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Re: the never ending project. 71 super build

Super_Randy wrote: November 4th, 2023, 2:31 pm edit:
well, i got it idling. kinda. at like 400rpm so im back at ground zero! :roll:
What was causing it not to idle?
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Super_Randy
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Re: the never ending project. 71 super build

no idea! but i had just taken the battery off the charger so...
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Super_Randy
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Re: the never ending project. 71 super build

well today was interesting. pulled the idle jet. blew the piss out of it with about 60psi of air only to have it syphon all the gas in the float bowl down the carb throat even after i stopped blowing air. that was interesting. so now there's gas in the oil. :roll: ask me if i give a shit at this point. :evil:
the only thing iv noticed in messing with it this weekend is that it gives more effort to idle when it's on the battery charger. and no matter what, the volt gauge reads about 11 volts even though the battery (according to a fluke meter) reads 12.6volts.

im down to thinking, there's ether some kind of vacuum leak somewhere i haven't found yet. or iv got some kind of electrical issue (engine ground maybe?). or the generator just isn't supplying enough juice to run the ignition system. idk. im confused, short tempered and loosing interest.
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Super_Randy
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Re: the never ending project. 71 super build

pulled the carb off today. pulled all the jets and needles and everything out, blew the piss out of it with compressed air and carb cleaner. not sure if it actually cleaned out any debris. had a suspicious fleck on the throttle plate. don't know where it came from, don't know if it came from inside the carb or not.
changed the air correction jet. my old carb and my original German carb both had the same jet in it, the new carbs was different so i threw in an old one cause reasons.
attempted to cap off the intake manifold and blew compressed air down it in an attempt to look for vacuum leaks. didn't notice anything. figured why not and looked at the vacuum line with a screw in it plugging the vacuum port on the 3/4 intake manifold. that line ain't coming off! but i did get the screw out and coated it in RTV and stuffed it back in there globing it up around the end cause im really just throwing shit at the wall at this point.
swapped out the idle cut off solenoid cause i had one. again, throwing shit at the wall.
took the ground wire off the generator and wire brushed the living hell out of the eyelet and generator. again, more shit flung at the wall.

the floatbowl and fuel filter were close to empty when i opened the decklid this morning. never had that happen before. it's only been a week, usually they're both still full :? so that's concerning.

so tomorrow after that RTV has had time to cure ill go crank it up again and see what happens.

also wondering if the vent line on the gas tank is clogged... might try taking the gas cap off during testing...
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schwim
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Re: the never ending project. 71 super build

You think maybe the vacuum at the tank pulled the fuel from the carb? That couldn't happen I don't think as the fuel comes in from the top at the needle.
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