1980 Carburetor flooding

rotaeng · 02-22-2012, 06:47 PM

I recently rebuilt engine and carburetor on 1980 Rx7 (12A).
The Nikki Carburetor is flooding such that there is gas pooling in the carburetor barrels.
I can get it started and idling although if I run up the RPM's or drive it, it will flood and stall. Appears to do this from the front barrels/float.
Twice I have removed the air horn, set the floats, EXACTLY, as recommended in the manual. I removed and sprayed carburetor cleaner through the air jets. No plugging found. Needle valve freely moves.
Float bowl solenoid valve is working.
I have looked at a several manuals and troubleshooting sources on this and cannot determine what the problem is.
Does anyone have any thoughts? Or do you know of someone I could send this carburetor to, to have it bench tested or looked at?
Thanks!

12arotary · 02-22-2012, 08:51 PM

just curious but did you break in the engine before the carb issue? i could see problems developing if its a fresh rebuild that the first starts are with a bad carb. but is fuel puddling in all four barrels or just the secondaries/primaries? does it flood when you have just the ignition on and not cranking?

Rich@SR · 02-22-2012, 09:43 PM

Quote:

Originally Posted by 12arotary

just curious but did you break in the engine before the carb issue? i could see problems developing if its a fresh rebuild that the first starts are with a bad carb. but is fuel puddling in all four barrels or just the secondaries/primaries? does it flood when you have just the ignition on and not cranking?

Agreed... wonder what the response is.

Kentetsu · 02-24-2012, 10:35 PM

Here you go: http://www.nellump.net/peri/epi/firs...odedCarbs.html

That should cover just about every reasonable possibility. Its a great article, so I don't bother writing it all out anymore for the new guys.

Let me know how it works out for you.

.

rotaeng · 02-26-2012, 12:44 PM

Thanks for all the help! Today I note that it is the front primary that is flooding with just the ignition turned on. The front bowl level is high through the sight glass. I cannot get a good look at the rear sight glass although this is not where the flooding is coming from. I am assuming there may be a binding of the needle/seat assembly, although both times I checked this it appeared to be moving freely. Is there some secret to making this move freely? I also read about a potential problem with a clogged emulsion tube or air bleed. Does anybody have any thoughts on this?

Thanks again. This carburetor is driving me crazy.

rotaeng · 02-26-2012, 02:32 PM

It is both the front primary and secondary flooding with ignition turned on. I just pull air horn again to recheck. No change with flooding.

dr1vn · 02-27-2012, 12:00 AM

did you buy and use a new fload needle or old one? exactly what did you replace and or clean ? my best educated guess for you is theres nothing wrong with the float itself and decent chance you got the attaching part pretty close to right good chance nothing wrong with air bleed {im also winging it i dont have much to go on just a problem to narrow down }but that the needle tip itself is not sealing to carb base or sealing poorly at best .. was it gumbed up with trash when you pulled old needle? and you cleaned it? or was there no trash? buy a new float needle? if thats the case your new needle isnt confoming to the shape of base of carb to form a seal that is my basic awnser but youve raised alot of questions

rotaeng · 02-27-2012, 09:43 PM

I rebuilt the carburetor with a kit, with new needle valve assembly. I will try replacing this to see if it helps.
Thanks for taking your time to help me with this!

dr1vn · 02-28-2012, 08:03 AM

oh 1 thing i forgot to mention about new float needles.. they need to be "seated" whitch means lining the needle up exactly as it will go in when finished all way in and give it a tap at top with hammer... a firm tap not a big hit ! it conforms the maluable bronze to the aluminum base - rule of thumb i use / hard enough to instantly break a lightbulb and touch table with noise but no harder than you would hit your finger!! only do it once <this is old trick ive learned > ive sometimes seen word seated used in carb books but rarely do they explain it .. and to your float question once seated the float s weight should with gravity alone pick up the needle -needle shouldnt be wobbly either your car breaks corners and accelerates lol if you think its little firm after a check up of finished set up and might need to unbind a touch after seating use just a {very light} glaze of 2-stroke on needle shaft but not the tip == the reason i think its flodding with ignition on is the car s fuel system thinks its running so pump builds pressure in line and continues to do so thinking it needs enough to need to be fully fueled and ignition off since its not gravity fed it just runs out of fuel to flood with and things just kinda sit there

Kentetsu · 02-29-2012, 06:58 AM

If only the front bowl is flooding, try banging on the top of the carb before you bother pulling it back off. Sometimes you can "jiggle" then into position without disassembly.

02-22-2012, 06:47 PM	#1
rotaeng The Newbie Join Date: Feb 2012 iTrader: (0) Posts: 5 Rep Power: 0	1980 Carburetor flooding I recently rebuilt engine and carburetor on 1980 Rx7 (12A). The Nikki Carburetor is flooding such that there is gas pooling in the carburetor barrels. I can get it started and idling although if I run up the RPM's or drive it, it will flood and stall. Appears to do this from the front barrels/float. Twice I have removed the air horn, set the floats, EXACTLY, as recommended in the manual. I removed and sprayed carburetor cleaner through the air jets. No plugging found. Needle valve freely moves. Float bowl solenoid valve is working. I have looked at a several manuals and troubleshooting sources on this and cannot determine what the problem is. Does anyone have any thoughts? Or do you know of someone I could send this carburetor to, to have it bench tested or looked at? Thanks!

02-22-2012, 08:51 PM	#2
12arotary tumor-syphilis-itis-osis Join Date: Sep 2008 iTrader: (0) Posts: 191 Rep Power: 17	just curious but did you break in the engine before the carb issue? i could see problems developing if its a fresh rebuild that the first starts are with a bad carb. but is fuel puddling in all four barrels or just the secondaries/primaries? does it flood when you have just the ignition on and not cranking? __________________ 82 300d 82 Gsl 84 b2200 Diesel 88 gxl

02-24-2012, 10:35 PM	#4
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	Here you go: http://www.nellump.net/peri/epi/firs...odedCarbs.html That should cover just about every reasonable possibility. Its a great article, so I don't bother writing it all out anymore for the new guys. Let me know how it works out for you. . __________________ "Learn from the past, or it will become your future...." '85 GS 12a + LSD/Sterling carb/Respeed coilovers/Respeed front swaybar/Respeed adj. rear spring perches/Illuminas/Bilsteins on rear AutoX vids @ http://www.youtube.com/user/Kentetsu1

02-26-2012, 12:44 PM	#5
rotaeng The Newbie Join Date: Feb 2012 iTrader: (0) Posts: 5 Rep Power: 0	1980 carb flooding Thanks for all the help! Today I note that it is the front primary that is flooding with just the ignition turned on. The front bowl level is high through the sight glass. I cannot get a good look at the rear sight glass although this is not where the flooding is coming from. I am assuming there may be a binding of the needle/seat assembly, although both times I checked this it appeared to be moving freely. Is there some secret to making this move freely? I also read about a potential problem with a clogged emulsion tube or air bleed. Does anybody have any thoughts on this? Thanks again. This carburetor is driving me crazy.

02-27-2012, 09:43 PM	#8
rotaeng The Newbie Join Date: Feb 2012 iTrader: (0) Posts: 5 Rep Power: 0	1980 carb flooding I rebuilt the carburetor with a kit, with new needle valve assembly. I will try replacing this to see if it helps. Thanks for taking your time to help me with this!

02-26-2012, 02:32 PM	#6
rotaeng The Newbie Join Date: Feb 2012 iTrader: (0) Posts: 5 Rep Power: 0	It is both the front primary and secondary flooding with ignition turned on. I just pull air horn again to recheck. No change with flooding.

02-27-2012, 12:00 AM	#7
dr1vn The Newbie Join Date: Jun 2010 iTrader: (0) Posts: 9 Rep Power: 0	did you buy and use a new fload needle or old one? exactly what did you replace and or clean ? my best educated guess for you is theres nothing wrong with the float itself and decent chance you got the attaching part pretty close to right good chance nothing wrong with air bleed {im also winging it i dont have much to go on just a problem to narrow down }but that the needle tip itself is not sealing to carb base or sealing poorly at best .. was it gumbed up with trash when you pulled old needle? and you cleaned it? or was there no trash? buy a new float needle? if thats the case your new needle isnt confoming to the shape of base of carb to form a seal that is my basic awnser but youve raised alot of questions

02-28-2012, 08:03 AM	#9
dr1vn The Newbie Join Date: Jun 2010 iTrader: (0) Posts: 9 Rep Power: 0	oh 1 thing i forgot to mention about new float needles.. they need to be "seated" whitch means lining the needle up exactly as it will go in when finished all way in and give it a tap at top with hammer... a firm tap not a big hit ! it conforms the maluable bronze to the aluminum base - rule of thumb i use / hard enough to instantly break a lightbulb and touch table with noise but no harder than you would hit your finger!! only do it once <this is old trick ive learned > ive sometimes seen word seated used in carb books but rarely do they explain it .. and to your float question once seated the float s weight should with gravity alone pick up the needle -needle shouldnt be wobbly either your car breaks corners and accelerates lol if you think its little firm after a check up of finished set up and might need to unbind a touch after seating use just a {very light} glaze of 2-stroke on needle shaft but not the tip == the reason i think its flodding with ignition on is the car s fuel system thinks its running so pump builds pressure in line and continues to do so thinking it needs enough to need to be fully fueled and ignition off since its not gravity fed it just runs out of fuel to flood with and things just kinda sit there

02-29-2012, 06:58 AM	#10
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	If only the front bowl is flooding, try banging on the top of the carb before you bother pulling it back off. Sometimes you can "jiggle" then into position without disassembly.