200 RPM Idle :(
10-15-10, 08:32 PM
#28
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10-16-10, 04:51 PM
#29
I checked the vacuum lines and couldn't find any that were unplugged, but I will go over them again just to make sure. I also messed with all the screws that looked like the adjusted something and there was no dramatic change in anything, I will grab a picture then so you can see my carb, there also might be one in one of my albums. I'm heading out to dinner so I will get one in a bit.
10-17-10, 10:06 AM
#30
Well here are the pictures, As you can see on each side it looks like there are 3 ''screws" for adjusting things. I'm not quite sure which one does what but they are mostly screwed the whole way in because that's where they were when I got the car so I haven't messed around with them at all besides when I just screwed them out to see if there would be any difference in the idle. There is another screw on top that adjusts something right where the fuel goes in, my guess right now is the idle for that one but I don't know. I really need to get this car running asap because my brother comes home from out west in a couple of weeks and I won't have a car to drive once he gets home if this isn't running. Thanks for all the help.
The whole carb
Side of the carb where it attaches to the intake manifold. (I cannot determine the maker of the intake manifold)
3 screws on right side of the carb. By right side I mean looking at it from passenger side of the car.
Left side of the carb. There is a vacuum hose in front of the 3rd screw.
Top of the carb where the fuel enters and there is a screw right beside there that adjusts something.
Any and all help is appreciated. I might end up tearing apart the carb again today and if I do, I will snap some pictures. If there is any picture requests of a place or piece, please let me know. Thanks.
The whole carb
Side of the carb where it attaches to the intake manifold. (I cannot determine the maker of the intake manifold)
3 screws on right side of the carb. By right side I mean looking at it from passenger side of the car.
Left side of the carb. There is a vacuum hose in front of the 3rd screw.
Top of the carb where the fuel enters and there is a screw right beside there that adjusts something.
Any and all help is appreciated. I might end up tearing apart the carb again today and if I do, I will snap some pictures. If there is any picture requests of a place or piece, please let me know. Thanks.
10-17-10, 02:57 PM
#31
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i don't know anything specific about the mukini, but i have gone to weber school... if i were you i'd try to find a diagram of the carb, just so you know what does what. don't be afraid to play with it either, once you know what each part of the carb does it really takes away all the "magic"
1. looks like the idle mixture screw. if the carb was jetted properly, and is idling on the idle circuit this will affect the idle mixture. carb these get turned in gently all the way, and then backed out. if its a factory car its usually 2.5 turns. since yours isn't factory, just turn the 2 of them so they are even, and it runs the best. all the way in is lean, all the way out is rich.
2. dunno, if you're lucky its an idle air bleed. setting it kind of requires a baseline from #1 and the idle speed screw, or throttle stop to be set right. if you do decide to play with it, mark where you are now, so you can put it back. unscrewing it = more air
3. probably a plug, the transition holes are under there, that's how they drilled em at the factory, since its a screw, it makes it easy to clean and inspect.
if you want the "how to tune the carb" paper, PM me your email. you will have to translate from weber to mukini too. all these carbs have the same parts, they just have different names
1. looks like the idle mixture screw. if the carb was jetted properly, and is idling on the idle circuit this will affect the idle mixture. carb these get turned in gently all the way, and then backed out. if its a factory car its usually 2.5 turns. since yours isn't factory, just turn the 2 of them so they are even, and it runs the best. all the way in is lean, all the way out is rich.
2. dunno, if you're lucky its an idle air bleed. setting it kind of requires a baseline from #1 and the idle speed screw, or throttle stop to be set right. if you do decide to play with it, mark where you are now, so you can put it back. unscrewing it = more air
3. probably a plug, the transition holes are under there, that's how they drilled em at the factory, since its a screw, it makes it easy to clean and inspect.
if you want the "how to tune the carb" paper, PM me your email. you will have to translate from weber to mukini too. all these carbs have the same parts, they just have different names
10-17-10, 04:38 PM
#32
Well, I did some researching early this morning and found 2 great resources for Mikuni Carbs. If anyone wants to post these somewhere and have them saved in the archives for other people who have a hard time finding things for their Mikunis, that would be good.
http://www.mikunipower.com/PHH01.htm
http://www.wolfcreekracing.com/index...d=21&Itemid=30
I didn't get much time to look through and read too much because I went with my dad to SAAC Shelby meet in Hershey today and I just got back. There isn't much daylight left and I want to drain the tank quick and put in new gas and see what happens. I will read through them later tonight once daylight runs out. I found out mine is the PHH 44mm, and even though Wolf Creek Racing is all about Datsun's, they have some good info.
http://www.mikunipower.com/PHH01.htm
http://www.wolfcreekracing.com/index...d=21&Itemid=30
I didn't get much time to look through and read too much because I went with my dad to SAAC Shelby meet in Hershey today and I just got back. There isn't much daylight left and I want to drain the tank quick and put in new gas and see what happens. I will read through them later tonight once daylight runs out. I found out mine is the PHH 44mm, and even though Wolf Creek Racing is all about Datsun's, they have some good info.
10-17-10, 06:49 PM
#33
Well I drained the tank tonight and walla, no success. 
But I did take some videos so you guys would get a better idea of what was going on. Here they are...
http://www.youtube.com/watch?v=_ft-oH70Rr8
In this video, I have the choke on, then I take it off, the idle drops way too much...
http://www.youtube.com/watch?v=5YK6jOzVfrU
In this video, I rev the car, and at first it bogs down, so I let off or else it would die, then I get it to rev up to about 3000rpms...
http://www.youtube.com/watch?v=1w1MF1-hZzk
In this video, I unplug a vacuum hose connected to the carb and nothing really changes, I followed where it goes and unplug those places and nothing really changes. (The hissing noise is the choke because I can't work around the engine when it shakes so bad at low rpms.)
So do these videos help out at all? Sorry for bad quality, my camera isn't the best.
But I did take some videos so you guys would get a better idea of what was going on. Here they are...http://www.youtube.com/watch?v=_ft-oH70Rr8
In this video, I have the choke on, then I take it off, the idle drops way too much...
http://www.youtube.com/watch?v=5YK6jOzVfrU
In this video, I rev the car, and at first it bogs down, so I let off or else it would die, then I get it to rev up to about 3000rpms...
http://www.youtube.com/watch?v=1w1MF1-hZzk
In this video, I unplug a vacuum hose connected to the carb and nothing really changes, I followed where it goes and unplug those places and nothing really changes. (The hissing noise is the choke because I can't work around the engine when it shakes so bad at low rpms.)
So do these videos help out at all? Sorry for bad quality, my camera isn't the best.
10-18-10, 11:08 AM
#36
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its too bad you're so far away, it looks like it would be fun to play with.
10-18-10, 02:18 PM
#37
Yeah, it's really a pain how there are no close people around here who have RX7's (specifically 1st gens). All my car buddies have 240sx's, haha. There is a small rotary shop over in E-town, but the guy there doesn't know much about carbs or much about 1st gens. They mostly do work on second gens, and they do a good job with them. In Lancaster City there are some Puerto Ricans in there that like RX7's but I don't think they would really want to come all the way out to where I live and help, and it's really hard to get a hold of them. I'm going to tear apart the carb again today and see what I can find. I'll have the spec sheet this time too with all the little parts ID so that will help. If I can, I will update later tonight. I'll grab some pictures too if I remember.
10-19-10, 05:57 AM
#38
Well, I got to tear apart the carb yesterday, and it was helpful to have the manual. I was over at a buddies working on a lip for his 240 so I didn't get to grab any pictures. I think today I'm going to put it back on and run the car for a little bit and then take off the top and see what the floats look like. If there is gas in there, then I'm guessing that a passage way is clogged.
10-19-10, 04:20 PM
#40
This afternoon I was able to mess around with mixtures and the main jets and that stuff and so far nothing has changed. The floats were both filled well. I really don't know what this problem is anymore. I really need help here, all my knowledge is about spent. I'm just going to go over the basics for the rest of the afternoon and see if I missed anything. I really don't want to take this to a mechanic because I know that all mechanics around here know nothing about my car. I'm officially begging for help here.
10-19-10, 04:28 PM
#41
I did put some MMO in a couple days before the problem began, and the exhaust was shooting some small black carbon chunks out. Could this be the exhaust being clogged? Why would it not idle right if the exhaust is clogged though? And why would it sputter and bog too?
10-21-10, 05:57 AM
#42
So I took off the headers to make sure it wasn't the exhaust being clogged, and it wasn't. Rotaries are also very loud with no exhaust system, haha. The one intake manifold nut stripped last night so I have to use a dremel and cut that off when I get the time. I finished bleeding the brakes and they're good. But so far no progress on what the problem is.
10-24-10, 07:01 PM
#43
No luck yet, I dropped the tank and found out that I couldn't even get to the inside of it because the one screw was rusted and I didn't want to strip it so I put it back in, and the one nut on the intake manifold got stripped so I have to use a dremel to cut it off later this week and I found out I have 2 exhaust leaks that I have to fix sometime. I talked to my one buddy who is a mechanic and he's like I have no clue what the problem might be so he will be over to check it out one day this week hopefully, but so far nothing is working....
10-27-10, 10:05 AM
#45
Which air jet?
Normally, gentle torque is enough to hold them in place. You could probably use a SMALL drop of low-strength (blue) Loc-tite if you had to.
Being as the jets are all made of brass, you don't want to make it too hard to get back out again.
Normally, gentle torque is enough to hold them in place. You could probably use a SMALL drop of low-strength (blue) Loc-tite if you had to.
Being as the jets are all made of brass, you don't want to make it too hard to get back out again.
10-27-10, 10:18 AM
#46
It would be number 28 on this page, http://www.mikunipower.com/PHHCarbs/PHHservice23.jpg , I'm not at home right now so I can't take pictures but you can find the part name on page 24 here, http://www.mikunipower.com/PHH01.htm , there are two of them and they both move pretty freely when I apply throttle.
10-30-10, 05:12 PM
#48
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Gently lift the jet out of the carb and match it to the picture in the diagram you posted. Make sure the jet is not broken, and the threads are not stripping on either the jet or the carb itself. If you still have a problem, try the blue loc-tite as DivinDriver suggested, but be careful not to let any drip into the carb, or the inside of the jet--for obvious reasons. Given all the vibration from such a low idle, sounds like you are lucky you still have the jet. Let us know how it turns out.
