Tuning a 45 DCOE weber?
#1
Senior Member
Thread Starter
Join Date: May 2003
Location: Springfield MO
Posts: 290
Likes: 0
Received 0 Likes
on
0 Posts
Tuning a 45 DCOE weber?
So i gave up on my nikki, and ordered a 45 (that was three months ago,....but we wont go there) now I cant, for the life of me get it to run right.
when i started i (again, jut=st like the nikki) got the mixture and ilde srew mixed up (miss-comunication between me and the "supplier") so those where jacked by the time i got it to Ide anything under 3.5k, but i did, so i proceed to do what the "supplier" said to do to tune the carb which i couldnt do so i got on here and SEARCHED and found a good right up, that was almost the same procedure as ,y "supplier" gave me https://www.rx7club.com/showthread.p...t=weber+tuning
so i did this and the damn thing just doesnt even out; I will start it, get it Idling then turn the mixture screws in untill the engine trys to die then turn them out 1.5 times. sometimes i can and sometimes i can go all the way in with them and it wont effect the way the engine is running. so ide unscrew them to 3.5 turns out and adjust the idle and start over somehow adjusting the idle will make it different and turning them in again will make it do what its supposed to , when i gen it set, You know the 1.5 turns out from the cutout point itidles really lopey and sometimes its smooth but when i give it gas it always smokes??? and some times it will spit gass out the right tube( if ur on the right side of the car) it also sometimes just pours fuel out that tube on start up
Im lost and sorry for the long post im trying to convey my troubles, carb's just arent my strongest point
thanks
Dustin
when i started i (again, jut=st like the nikki) got the mixture and ilde srew mixed up (miss-comunication between me and the "supplier") so those where jacked by the time i got it to Ide anything under 3.5k, but i did, so i proceed to do what the "supplier" said to do to tune the carb which i couldnt do so i got on here and SEARCHED and found a good right up, that was almost the same procedure as ,y "supplier" gave me https://www.rx7club.com/showthread.p...t=weber+tuning
so i did this and the damn thing just doesnt even out; I will start it, get it Idling then turn the mixture screws in untill the engine trys to die then turn them out 1.5 times. sometimes i can and sometimes i can go all the way in with them and it wont effect the way the engine is running. so ide unscrew them to 3.5 turns out and adjust the idle and start over somehow adjusting the idle will make it different and turning them in again will make it do what its supposed to , when i gen it set, You know the 1.5 turns out from the cutout point itidles really lopey and sometimes its smooth but when i give it gas it always smokes??? and some times it will spit gass out the right tube( if ur on the right side of the car) it also sometimes just pours fuel out that tube on start up
Im lost and sorry for the long post im trying to convey my troubles, carb's just arent my strongest point
thanks
Dustin
Last edited by Chamele03; 07-02-04 at 12:38 AM.
#3
Whack 'em and stack 'em
Join Date: Mar 2003
Location: Clarksburg/Bridgeport WV- North Central Appalachia
Posts: 1,373
Likes: 0
Received 0 Likes
on
0 Posts
Gas spitting out? Maybe the banjo bolt needs to be tightened.
Do you have a single inlet banjo or the double? (Are you running a return line?)
Do you have a single inlet banjo or the double? (Are you running a return line?)
#4
RicanRider
Re: Tuning a 45 DCOE weber?
These settings are for a 12A Street Port. So I don't know if your engine is 12A or 13B street port or stock.
So here is an example of some settings. These works great on mine...
12A Street Port
WEBER 45DCOE JETTING
40mm Chokes
4.5 Auxiliary Venturies
Accelerator Pump Jet 50
Emulsion Tubes F11
Idle Jets 60F9
Main Jets 200
Air Corrector 180
Fuel Pressure 3.0psi
All carbs are different. So you might have to close both idle mixture screws and then turn one out until the car just bearly runs. Take note of how many turns it took. Then close it back and do the same to the other idle mixture screw. Then close it back. Now open both of them to what ever turns they let the engine run. Then start opening them 1/4 turn at a time on each mixture screw. Take notes so you know how many turns out you are. This will also could be used to get it back to a runing condition should you have to close them again.
The carb may have one mixture screw that needs to open more than the other in order to run the engine. I know, because mine was like that.
According to the book I have. Some carbs depending on what model it is. might need 1 1/2 turns out or some will need 2 turns out. That's why you should close them both and them open one idle screw out 1/2 turn at a time until you car stay runing. it will run but not quite good, you just want it to run even iif is erratic.. then do the same to the other screw. Once you got it running ruff, you can start the proces of adjusting them by turning them 1/4 to 1/2 turns out each at a time, allowing the car to settle for at leat a minute before adjusting again.
By the way the stock fuel pump will not be to good for a 45DCOE. I have a carter high volume pump set a 3.psi
anything more than that will cause the carb to flood...
So here is an example of some settings. These works great on mine...
12A Street Port
WEBER 45DCOE JETTING
40mm Chokes
4.5 Auxiliary Venturies
Accelerator Pump Jet 50
Emulsion Tubes F11
Idle Jets 60F9
Main Jets 200
Air Corrector 180
Fuel Pressure 3.0psi
All carbs are different. So you might have to close both idle mixture screws and then turn one out until the car just bearly runs. Take note of how many turns it took. Then close it back and do the same to the other idle mixture screw. Then close it back. Now open both of them to what ever turns they let the engine run. Then start opening them 1/4 turn at a time on each mixture screw. Take notes so you know how many turns out you are. This will also could be used to get it back to a runing condition should you have to close them again.
The carb may have one mixture screw that needs to open more than the other in order to run the engine. I know, because mine was like that.
According to the book I have. Some carbs depending on what model it is. might need 1 1/2 turns out or some will need 2 turns out. That's why you should close them both and them open one idle screw out 1/2 turn at a time until you car stay runing. it will run but not quite good, you just want it to run even iif is erratic.. then do the same to the other screw. Once you got it running ruff, you can start the proces of adjusting them by turning them 1/4 to 1/2 turns out each at a time, allowing the car to settle for at leat a minute before adjusting again.
By the way the stock fuel pump will not be to good for a 45DCOE. I have a carter high volume pump set a 3.psi
anything more than that will cause the carb to flood...
#5
Full Member
Join Date: Jun 2004
Location: Mid-America
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
So it seems that everyone agrees that the stock fuel pump sucks for the Weber upgrade. Alot of people I talk to say the Carter is a good pump, but I'm wondering about just putting a GSL-SE pump on there. Would that do the trick, and would a pressure regulator be necessary too?
#7
Senior Member
Thread Starter
Join Date: May 2003
Location: Springfield MO
Posts: 290
Likes: 0
Received 0 Likes
on
0 Posts
i am using the stock fuel pump with no return, but i was told this would work by Rob at rotary shack, and have no clue what jets are in it, I told him my setup and he went though the carb to set it up for me.
Trending Topics
#8
Full Member
Join Date: Jun 2004
Location: Mid-America
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
Really? I didn't think the stock pump moved enough fuel to really do the trick. I know that since I've put the Weber on there that there has been little, if any, increase in power. I dunno though, I'm kinda noob at this.
#10
Full Member
Join Date: Jun 2004
Location: Mid-America
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
That's not a half-bad idea. Has anyone ever used a Colortune? I wasn't terribly impressed with it, but it was fun to see the actual detonation. According the the Colortune, I'm running at ideal. Doesn't feel like it, though.
#11
Whack 'em and stack 'em
Join Date: Mar 2003
Location: Clarksburg/Bridgeport WV- North Central Appalachia
Posts: 1,373
Likes: 0
Received 0 Likes
on
0 Posts
You may find some useful info on this thread I started almost a year ago. I farted around with a 45dcoe on my stockport12A for a few months. It accelerated great, even down low but I had a pesky hesitation at crusing speeds. Since my car is really for long cruises (not WOT street dragging or racing) I opted to go BACK to a 4bbl Nikki. I'm working now on installing my modded Sterling Nikki (gotta find a vac leak- me thinks)
NOTE- I was tryng to tune an OLD style 45dcoe- so I would imagine your's should be easier. Check out the info:
https://www.rx7club.com/showthread.p...s&pagenumber=2
NOTE- I was tryng to tune an OLD style 45dcoe- so I would imagine your's should be easier. Check out the info:
https://www.rx7club.com/showthread.p...s&pagenumber=2
#12
Full Member
Join Date: Jun 2004
Location: Mid-America
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
I'm still learning how to handle it. I know I can't just floor it off the line, because it just dies. Feels like it needs more fuel at that point, but I won't know unless I test.
#14
Senior Member
Thread Starter
Join Date: May 2003
Location: Springfield MO
Posts: 290
Likes: 0
Received 0 Likes
on
0 Posts
aaahhhh....rgh man this is agravating me...... ok I did the; turn both mixture screws in and get on running then do the other thing, it took (from passenger side of car) 8 1/4 turns on the right and 18 on the left, so I put them at that and start it up, it started and idles with a little coaxing but it was missing (thats what it sounded like to me) but Iff i turned the idle down any it would try to die, it was idleing at about 1.7k, any opinions?
anyone know of a carb/weber shop in the springfield MO. area?
i was also wondering what are these screws doing inside the carb, like if i turn them out is it letting more air in or less, r more gas?
thanks
Dustin
anyone know of a carb/weber shop in the springfield MO. area?
i was also wondering what are these screws doing inside the carb, like if i turn them out is it letting more air in or less, r more gas?
thanks
Dustin
#15
Full Blown 1.1
Join Date: Jan 2013
Location: Seattle
Posts: 213
Likes: 0
Received 0 Likes
on
0 Posts
I'm having these same issues. I can tell for certain that my floats are not adjusted right. Can anyone please tell me the correct float adjustment specifics. I have all the jetting done for 12a streetport but this thing is flooding badly
#16
RX for fun
iTrader: (13)
once float level is set, adjust the fuel pressure regulator to lowest pressure possible, say 2.5, then gradually increase the pressure where fuel is not dripping inside the venturies.
#17
Work in Progress
iTrader: (9)
aaahhhh....rgh man this is agravating me...... ok I did the; turn both mixture screws in and get on running then do the other thing, it took (from passenger side of car) 8 1/4 turns on the right and 18 on the left, so I put them at that and start it up, it started and idles with a little coaxing but it was missing (thats what it sounded like to me) but Iff i turned the idle down any it would try to die, it was idleing at about 1.7k, any opinions?
anyone know of a carb/weber shop in the springfield MO. area?
i was also wondering what are these screws doing inside the carb, like if i turn them out is it letting more air in or less, r more gas?
thanks
Dustin
anyone know of a carb/weber shop in the springfield MO. area?
i was also wondering what are these screws doing inside the carb, like if i turn them out is it letting more air in or less, r more gas?
thanks
Dustin
#19
Junior Member
Join Date: Jul 2014
Location: Clarksville, TN
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Bringing this back
So i have read through this thread and the other linked, but am still having a ton of problems. I have a street ported 12a with the "weber" carb from rotaryshack.
Rotary Shack Custom Mazda RX-7 12A Weber Intake Kit | Rotary Shack Store
The guy i bought the car from told me it had jetting problems and to call them. I did and they suggested the jets I currently have in. They are not too far off from alot of the posts, just a little smaller. Ever since I installed the new jets it was a pain to start and it will not run under 3k RPM. With my reading i went through and replaced the regulator with a holly 1-4 psi. I dont know what the fuel pump is. Oh and it leaks fuel from the venturi. I thought that with lowering the fuel pressure that this would go away but now i think that i have to adjust the float level. Any help would be very useful. I really want to get her back on the road again, been sitting in the garage for almost 2 years now.
Rotary Shack Custom Mazda RX-7 12A Weber Intake Kit | Rotary Shack Store
The guy i bought the car from told me it had jetting problems and to call them. I did and they suggested the jets I currently have in. They are not too far off from alot of the posts, just a little smaller. Ever since I installed the new jets it was a pain to start and it will not run under 3k RPM. With my reading i went through and replaced the regulator with a holly 1-4 psi. I dont know what the fuel pump is. Oh and it leaks fuel from the venturi. I thought that with lowering the fuel pressure that this would go away but now i think that i have to adjust the float level. Any help would be very useful. I really want to get her back on the road again, been sitting in the garage for almost 2 years now.
#21
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 31,138
Received 2,797 Likes
on
1,979 Posts
if it leaks from the venturi at idle, that is step one, its ok in a race car, but a street car you should lower the float a little.
#22
Junior Member
Join Date: Jul 2014
Location: Clarksville, TN
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Quick up date, lowered float level and no longer leaks from the venturi. Still wont idle below 3k rpm, i pulled the idle jets and made sure they where not clogged. Perhaps is it my throttle plate adjustment?
#23
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 31,138
Received 2,797 Likes
on
1,979 Posts
the starting point for the throttle plate adjustment is to have the plate just above the 1st idle hole, and you can either take the carb off and measure directly. or just to start you can back off the throttle stop screw until it doesn't touch, screw it back until it does touch and then another 1/2 turn.
if it idles low, there is an air bleed you can adjust on a DCOE. the idle jets also have an air bleed in them too, 65F9 is a 65 fuel, and F9 air. so you can change either or both
if it idles low, there is an air bleed you can adjust on a DCOE. the idle jets also have an air bleed in them too, 65F9 is a 65 fuel, and F9 air. so you can change either or both