1981 new E4ME carb horrible idle
Thread Starter
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
1981 new E4ME carb horrible idle
Instead of rebuilding the original carb, I got a reman unit from I5 auto; installed it, new gasket, new filter. All stock, CCC system intact and operating properly, no CEL light after start up. Unplugging the dist 4 wire plug gives me a light so I now all is well there.
Idle is horrible after warm up....lumpy, surging. Holding my hand strategically over the choke plate after warm up I can make it idle smooth, so one would think it has a vacuum leak (running lean at idle); I pull each vac line individually, and cap the inlet with the correct rubber cap, and no change at all. The old carb runs better!
Getting ready to spray the shafts with ether to see if the re builder messed up a shaft seal / bushing, any other ideas to try?
Thanks.
Idle is horrible after warm up....lumpy, surging. Holding my hand strategically over the choke plate after warm up I can make it idle smooth, so one would think it has a vacuum leak (running lean at idle); I pull each vac line individually, and cap the inlet with the correct rubber cap, and no change at all. The old carb runs better!
Getting ready to spray the shafts with ether to see if the re builder messed up a shaft seal / bushing, any other ideas to try?
Thanks.
Race Director
Joined: Jul 2004
Posts: 12,708
Likes: 329
From: Scottsdale Arizona
It does sound like a vacuum leak. You might try spraying your solvent at the base of the carb to see if the idle changes.
Are all of the million odd rubber hoses in good shape and hooked up correctly?
Are all of the million odd rubber hoses in good shape and hooked up correctly?
Thread Starter
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
Thanks.
I pulled the carb off, tightened all the intake manifold bolts, tightened all the carb torx screws (they were loose!), cleaned the mating surfaces, reinstalled the carb. Checked all the hoses, their locations, it seems better now, but not silky smooth. Closing the choke plate a bit smooths it right out. Repeated pulling every vac line one by one and capping the inlet, none of them made any difference in the rpm or consistency.
Obviously lean at idle, will turning the idle screws out richen it up and help? Presently at 2 turns out from seat.
I pulled the carb off, tightened all the intake manifold bolts, tightened all the carb torx screws (they were loose!), cleaned the mating surfaces, reinstalled the carb. Checked all the hoses, their locations, it seems better now, but not silky smooth. Closing the choke plate a bit smooths it right out. Repeated pulling every vac line one by one and capping the inlet, none of them made any difference in the rpm or consistency.
Obviously lean at idle, will turning the idle screws out richen it up and help? Presently at 2 turns out from seat.
Race Director
Joined: Jul 2004
Posts: 12,708
Likes: 329
From: Scottsdale Arizona
If everything is working properly, I don't think you should have to touch the idle screws. The carb should self adjust if it's running lean. That's what the CCC is for.
What is your RPM at idle?
What is your RPM at idle?
Thread Starter
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
Race Director
Joined: Jul 2004
Posts: 12,708
Likes: 329
From: Scottsdale Arizona
My manuals are still boxed up do I can't check for sure, but 850 sounds like its right in the middle of the range. I don't think tinkering with the mixture screws will improve your idle ( unless the screws are uneven).
Are you sure that all of your plugs and wires are good?
How does it run at partial throttle?
How about at WOT?
Are you sure that all of your plugs and wires are good?
How does it run at partial throttle?
How about at WOT?
Instructor
Joined: Mar 2014
Posts: 104
Likes: 0
From: Frankfort IL
Instead of rebuilding the original carb, I got a reman unit from I5 auto; installed it, new gasket, new filter. All stock, CCC system intact and operating properly, no CEL light after start up. Unplugging the dist 4 wire plug gives me a light so I now all is well there.
Idle is horrible after warm up....lumpy, surging. Holding my hand strategically over the choke plate after warm up I can make it idle smooth, so one would think it has a vacuum leak (running lean at idle); I pull each vac line individually, and cap the inlet with the correct rubber cap, and no change at all. The old carb runs better!
Getting ready to spray the shafts with ether to see if the re builder messed up a shaft seal / bushing, any other ideas to try?
Thanks.
Idle is horrible after warm up....lumpy, surging. Holding my hand strategically over the choke plate after warm up I can make it idle smooth, so one would think it has a vacuum leak (running lean at idle); I pull each vac line individually, and cap the inlet with the correct rubber cap, and no change at all. The old carb runs better!
Getting ready to spray the shafts with ether to see if the re builder messed up a shaft seal / bushing, any other ideas to try?
Thanks.
Racer
Joined: Mar 2003
Posts: 448
Likes: 21
From: Klein Texas
Can you share a pic of the idle air bleed? That's if they didn't replace the cover.
If properly set up they are usually only a couple threads down the hole. It's possible the didn't replace, or cut the o-rings.
If properly set up they are usually only a couple threads down the hole. It's possible the didn't replace, or cut the o-rings.
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Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
I believe your mixture screws are off. I recently rebuilt my E4ME if I remember correctly the Mixture screws set up was 3 to 4 turns out from seated. Just make sure you know where they are now and turn them out, you can always put them back if it doesn't help.
Thread Starter
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
I have the shop manual; it runs well every where else, just the rough idle. Will check the mixture screws again. No cover over the idle air bleed. TPS adjustment screw cover in place.
Will start from scratch on the carb, get the dwell meter out and see where I can get.
Thanks for the pointers, will report back.
Will start from scratch on the carb, get the dwell meter out and see where I can get.
Thanks for the pointers, will report back.
Intermediate
Joined: May 2012
Posts: 31
Likes: 0
Interested to hear about your progress as I just replaced my carburetor with a rebuilt one from Mountain Man. I also had to make adjustments on choke, fast idle and then the mixture screw. I used the dwell and have it at approximately 31 degrees. Car idles ok at around 700 (850) in park. However, it is not a silk smooth idle (consistently). When the air conditioning is on, the idle goes up to about 800 and it is very smooth. I also changed the plugs and the wires are relatively new as well. I haven't check to see if the rich and lean screws are even, so that is next. Any other comments or recommendations would be greatly appreciated.
Intermediate
Joined: May 2014
Posts: 30
Likes: 0
I have the shop manual; it runs well every where else, just the rough idle. Will check the mixture screws again. No cover over the idle air bleed. TPS adjustment screw cover in place.
Will start from scratch on the carb, get the dwell meter out and see where I can get.
Thanks for the pointers, will report back.
Will start from scratch on the carb, get the dwell meter out and see where I can get.
Thanks for the pointers, will report back.
Thread Starter
Racer
Joined: Nov 2011
Posts: 319
Likes: 12
From: South Chase WI
OK.
Started over. Spec on the idle screws is 3 and 1/3 out from seat. Did that. They were at 2 turns. Got the dwell at 30 degrees in drive by adjusting the idle air bleed, it was WAY off. Re set the timing and idle, re adjusted the fast idle solenoid.
Much better....could still fine tune a bit more, but it is a whole new world now at idle and runs just great. No stumble coming down to a stop, no hesitation off idle accelerating.
Happy day, now to figure out the small vibration I have at 45 mph......
Started over. Spec on the idle screws is 3 and 1/3 out from seat. Did that. They were at 2 turns. Got the dwell at 30 degrees in drive by adjusting the idle air bleed, it was WAY off. Re set the timing and idle, re adjusted the fast idle solenoid.
Much better....could still fine tune a bit more, but it is a whole new world now at idle and runs just great. No stumble coming down to a stop, no hesitation off idle accelerating.
Happy day, now to figure out the small vibration I have at 45 mph......