39 replies to this topic

[greenleafar]

Thanks for all of the advice guys. i havent had any time recently to work on the ford/honda carb "project" since i have started work. and its starting to look like ill have to give up on it. for now atleast. i need the car. that truck wastes just way too much gas. and i travel 60-65 minutes everymorning to get to work. it really killing me on gas. so, im gonna have to get a stock carb on there pretty soon. i bought one off of 87crexsi. i just need to clean it up, plug it up for the devac, and put it back on there. im gonna do that today since i have the day off.

oh, and kaymo, greenleafar. my name is Rafael. leafar = Rafael backwards. and green is my favorite color. therefore: greenleafar. pretty simple once you know my real name, really.

[kaymo]

suuure. thats what they alllll say. pothead. lol

block off your egr and air valve and rebuild a stock carb. after devac you should be pleasantly suprised with the new throttle response. mine was excellent even on a 1.3

[greenleafar]

egr, air valve? well, im doing whats on the devac writeup i found on here. i dont really recall seeing that on there, though. unless im mistaken. ill look into that though. i just spent the last 2 hours cleaning the outside of the carb i got, it was that dirty. i plan on doing a rebuild once i get a kit. anybody know where i could find a cheap one btw?

[kaymo]

yes. honda dealership. they have the cheapest price LOL believe it or not

and you dont want to get it anywhere else because i had seals in mine that didnt fit right and i had to replace them with honda seals.

[greenleafar]

ok. honda dealership it is then. but that will have to wait a bit for now.

yesterday, i cleaned up the carb, and i plugged the vacum ports that were specefied on the devac write up on this forum, i put it on and cracked it up. and, well, it started, and stayed on. but it was kept going from 3.5-5 k. it would just go back and forth slowly. i hit the gas, and it doesnt go up. it kinda slightly goes down and it sounds like as if the engine is slightly muffled. i dont know how to explain it. after a few tries, i had to stop as i had to go to band practice. i work nights, so i just got home and im gonna rest. but once i get a chance, im gonna see if messing with the idle screw will help. any body got any advice?

[greenleafar]

well, after playing around a bit with the carb, i finally got it to a good 1.25 or so rpm. i found that the little metal flap (dont know what its called, yeah, i know, noob) wasnt quite working just right. it didnt open all the way when i pulled on the throttle and it didnt really close all the way either, which i dont think its meant to anyway. ill try to get pics later is someone needs em.

but other than that, the car runs good. apart from being a real pain in the but to start, it drives fine, with some real "pep" if you will, atleast in the second half of the rpm range. at first, the throttle felt a bit sluggish, but after messing with that metal fly thing a bit, it felt alot more responsive.

one thing i am worried about though, is that when i have the car on, and its idlling at 1.25 or so, i open that flap i keep mentioning and the rpm goes up considerably. i dont know how much as im outside of the cockpit. is this supposed to be like that? im worried that the carb is wasting more gas than neccesary. if it doesnt open properly when i accelerate, then to get it to go higher, theres more gas being thrown in there. if the flap opened more, like i think it should, then it would rev up more as i accelerate, right? i dont know, maybe im over thinking this whole thing a bit. but it really doesnt seem as that flap is opening like it should. in any case, i think a rebuild is necessary.

but other than that, im really happy with the cars progress!! yay, i can finally drive it.

Edited by greenleafar, 19 March 2009 - 03:44 PM.

[Captain Regular]

well, after playing around a bit with the carb, i finally got it to a good 1.25 or so rpm. i found that the little metal flap (dont know what its called, yeah, i know, noob) wasnt quite working just right. it didnt open all the way when i pulled on the throttle and it didnt really close all the way either, which i dont think its meant to anyway. ill try to get pics later is someone needs em.

but other than that, the car runs good. apart from being a real pain in the but to start, it drives fine, with some real "pep" if you will, atleast in the second half of the rpm range. at first, the throttle felt a bit sluggish, but after messing with that metal fly thing a bit, it felt alot more responsive.

one thing i am worried about though, is that when i have the car on, and its idlling at 1.25 or so, i open that flap i keep mentioning and the rpm goes up considerably. i dont know how much as im outside of the cockpit. is this supposed to be like that? im worried that the carb is wasting more gas than neccesary. if it doesnt open properly when i accelerate, then to get it to go higher, theres more gas being thrown in there. if the flap opened more, like i think it should, then it would rev up more as i accelerate, right? i dont know, maybe im over thinking this whole thing a bit. but it really doesnt seem as that flap is opening like it should. in any case, i think a rebuild is necessary.

but other than that, im really happy with the cars progress!! yay, i can finally drive it.

Those "metal flaps" you're referring to are the throttles themselves. I think, anyway, if I'm picturing this correctly. When those open up they expose the throats of the carb (the big tubes that go all the way down through the carb and have little holes in the side to let air and fuel in) to the vacuum suckage of the engine, thus pulling fuel down. When they're closed, the engine suck doesn't pull any (or much) fuel/air mix down, but when you open them up - more power! THAT is whan your idle SPEED screw (the easy one to adjust, on the pass side front of the carb) opens up a little bit, and it's why adjusting that screw is effectively the same as saying "this is how much (a tiny bit, anyway) the gas pedal will always be down, at a minimum." You could "manually" do the same thing by constantly holding down ever so slightly on your gas pedal. That screw just does it for you. That screw and your idle MIXTURE screw (in the lower back of the carb) are what are going to control your idling.

It sounds like your throttles are working well enough, and that 1.25 idle speed isn't bad. I've got mine around 1.1, but it's pretty warm here and I can get away with it. The throttles opening as they should, that's different. On a stock Honda carb setup, you use TWO throttle plates (three if you count the tiny one for the CVCC system, remember that?) and the one opens up later, as you push the pedal down more. It's the "secondary" and should only kick in when you call for that extra power. I drive my DX like an old lady, so my secondary doesn't open up very often. I actually started having a "wobbly" idle last week, and was going to adjust the mixuture and the speed and check the float. It stalled once or twice, and I was ready for a weekend carb rebuild. But all I had to do was floor it for a few seconds, really open it up and take off like a madman, and that apparently "unstuck" whatever was stuck. Back to normal now. Didn't even have to open the hood.
Anyway, the STOCK setup uses that complicated as hell vacuum system to open the secondary throttle. The primary is still done with your gas pedal cable. What DarkHand discovered, though, is that when you do a devac and link that diaphragm arm that controls the secondary to the vacuum on the carb, it either weakens the secondary so it never kicks in, or it COULD provide enough that it holds it open permanantly, meaning you can't slow your engine down. That would be very bad. So he devised a system using zip ties (I did this myself, works great) that simply takes OFF the secondary vacuum diaphragm, doing aways with it (I hacksawed mine off the bracket) and now gives you mechanical control over it. It opens perfectly now as you push the throttle further, and no vacuum control to mess with. It actually DOES sound like your carb is working properly. The "bitch to start" can be fixed easily with a manual choke, of which I am a BIG fan. Other than the devac as a whole, it's the best thing I did with my carb. The electic/vacuum choke system is complicated. It works well enough, but after a devac it becomes far less predictable and reliable, I think. I forget off the top of my head which throat is primary vs secondary, but I THINK the secondary is the bigger one. The primary opens first when you pull the throttle cable. Look in the Carburetor Research thread to find that zip-tie mod, it's great.

[kaymo]

it sounds like the "metal flap" he is talking about is the choke flap. opening it would allow the rpms to increase.

it does still sound like you need a rebuild, but here is a trick a old carb guy gave me. rev the engine up using only the primary (smaller throttle plate) once engine RPM is up say 2500 or so, dump the throttle wide open so that the secondary opens but at the same time, COVER the choke and primary COMPLETELY with your hand. it will start to stall if you dont keep the secondary open. it will make a funny noise lol but what it does is puts alot of vacuum pressure where it normally wouldnt see it, possibly clearing out clogged passages. capitan regular it sounds like this might help you out. he told me he had "fixed" many a carb by doing that.

anyway, if your engine is running decently (besides carb) then getting your idle down to factory specs 750 +_ 50 is not really that far fetched. for a while i couldnt get my idle down from about 1100 or so, but i discovered the throttle return spring had lost its will to hold the throttle closed. i could have wound the spring around once more, but instead i just added a chevy carb return spring. then i was able to play with it and set it even as low as about 600 rpm and it was smooth as silk. man i had the carb dialed in PERFECT.... right before the engine blew up. i would kill for a good running 1.3... long block

[Captain Regular]

it sounds like the "metal flap" he is talking about is the choke flap. opening it would allow the rpms to increase.

it does still sound like you need a rebuild, but here is a trick a old carb guy gave me. rev the engine up using only the primary (smaller throttle plate) once engine RPM is up say 2500 or so, dump the throttle wide open so that the secondary opens but at the same time, COVER the choke and primary COMPLETELY with your hand. it will start to stall if you dont keep the secondary open. it will make a funny noise lol but what it does is puts alot of vacuum pressure where it normally wouldnt see it, possibly clearing out clogged passages. capitan regular it sounds like this might help you out. he told me he had "fixed" many a carb by doing that.

anyway, if your engine is running decently (besides carb) then getting your idle down to factory specs 750 +_ 50 is not really that far fetched. for a while i couldnt get my idle down from about 1100 or so, but i discovered the throttle return spring had lost its will to hold the throttle closed. i could have wound the spring around once more, but instead i just added a chevy carb return spring. then i was able to play with it and set it even as low as about 600 rpm and it was smooth as silk. man i had the carb dialed in PERFECT.... right before the engine blew up. i would kill for a good running 1.3... long block

Huh, not sure how the hell I neglected to think of the choke plate. And that hand-covering with the throttle wide open (I'll call it a super-choke) technique really could clear out passages. I've gotten real good with basic carb operation, but I'm rusty on the details of all the carb "accessories" like the electric choke system and the vacuum system and all that stuff that my carb hasn't had in forever. I don't know if mine was clogged passages or a sticky spring, but it's been fine for a week now. I doubt it was clogged, I've got a pair of brand new fuel filters, and they still look clean as anything.

To greenleafar about your CHOKE plate then, can't believe I didn't think of THAT when you said "metal plate." When it's open, you're letting more air into the carb, meaning the engine suction pulls more air than fuel, making it leaner. Once the engine is warm, you'll want it as open as possible, all the way. It'll give you the best economy and the most power. However, when it's cool or cold, you need to close it off some or a lot (but never QUITE 100%) to get enough fuel into the engine to start it. Basically, when you first go to start the car, it should be mostly closed, and the automatic system SHOULD open it up slowly over a short period while the engine warms up. Once the engine is running and hot, it should be all the way open. The plastic thermovalves on the intake manifold, the vacuum control boxes and a whole bunch of other stuff contribute to the system to open it automatically, making it quite complicated. I just took my ENTIRE choke system off, and use a manual choke. It takes a bit of practice, but I think it's well worth it. But basically, that choke plate won't and shouldn't open very quickly, it should only be open AFTER the engine is hot and running.

[kaymo]

my choke still worked just fine after devac... the bi-metallic spring is really what does it all. the other stuff i think just assists. i was going to look into a manual choke, but after lots of driving and normal visits to friends houses and no start up issues, i forgot all about messing with it.

i know alot of people have issues with their carb, and i definitely had issues with mine! but after rebuild i guess i was just very lucky that everything seemed to work well. i will say i did spend alot of time playing with my idle mixture screw (and not really knowing what i was doing anyhow..) and my idle screw, but in the end it would purr like a kitten and rev like a scalded wildcat. that carb is the only reason i am remotely interested in rebuilding that damn engine. otherwise it would be scrap by now...