86’honda civic dx 1.5- Car runs fine when warm. When cold has a very high idle. Base gasket/phunalic seems loose and leaks. (looking-auto supply is a no go-to old;) Vac hose are good. when cold she wound up like my Xwife. About 2500+ but when warm she drops to normal rpm.(the car, x is never normal;) Parts house dont have chilton back that far. Hanes are CRAP and only good for starting fires when camping… I need a good vac. diagram and help finding parts to fix base leak. Would use ultra gray but would like to fix it right 1st. I.m and OLD mech. but only detrot not import. My fix for the old hondas was 2 gal of gas mixed with match. Followed with a cold beer and big smile. Less stress…But I get 40mpg and like spending my $ on my plane. Any help or ideas?
Thank you,
May the GREAT SPRIT keep you.
walka
There was another recent thread concerning early (or late) Honda carburetors…The whole issue was discussed at length…Fortunately for the vintage Honda’s owner, the problem turned out to be a set of plug wires…I’ll see if I can find that discussion and bump it up where you can find it…
Search for “Honda Civic Carburetor”
If the engine idles pretty much normally when warmed up then I don’t think a vacuum leak is the problem; unless the carburetor is running excessively rich. Have you actually verified there’s a leak by the use of a vacuum gauge or by applying an aerosol carb cleaner or even WD-40 to the suspected leak?
Maybe the exessively fast idle (about 1500 is more normal) is caused by:
Fast idle screw turned in too much.
Fast idle cam or linkage hanging up.
Linkage problem with the secondaries.
That’s the short form on these things. It could get much deeper depending on the minutae details.
In the past, I’ve had to make my own gaskets from time to time. I don’t like using ‘Gorilla Snot’ on carburetors because there’s too many things that can get plugged up with that stuff. Getting a sheet of gasket material, a sharp pencil, and a X-acto knife or utility knife has served me well in cases like this. Most auto parts sell or can get gasket material, both cork and paper, in full sheets.
Take the existing gasket, or the pieces you have left over, place it on the gasket sheet, trace the shape and all the internal voids, then carefully cut it out. It has worked for me on a lot of older cars with hard-to-find parts.
The Honda 3 bbls had several vacuum pots controlled by the mystery box on the fire wall. That sounds like the source of the problem. A good shop manual would likely make for an amicable resolution.I have had some success with Alldata but won’t stick my neck out on this problem. If all else fails you might give them a try. Please keep us posted.
Actually, I don’t think that 2500 for a cold idle is too high on this one. I’d leave it alone, maybe snug up the carb mounting nuts a little, but thats about it.
There’s a 1986 Civic factory manual on ebay right now for $36. Search for 140631313848.
That’s more than the car is worth…And frequently, the carburetor, part of the emissions control system, has a shop manual all its own!
Thanks to ALL for your time. May your CHRIST-mas be blessed with peace.
1st- 2500+ is whay too high and on a cold eng. NO! 1800 - 2000 tops…
Searching for manual…
Dose anybody know what controls the vac. for the fast idle? Is it in the “mystery box” on firewall ? Or there is allso one on the driver fender. The one on the firewall seems to be the “blackhole” of vac. lines…
P.S. I just bought me a new ultralight so I need to fix the carb. (merryXmas too mee;}
THANKS to all and MERRY CHRISTMAS!!!
walka
PSS…Ebay manual was eng. wireing.
But THANKYOU
CANDDYMAN— Followed your link back to old threads. THANKx, Got some pic.s from blackbird of the vac. system. Not my year but its a start… This car has NEVER been touched. It has just been used from time to time and thats on long trips. She is what “pilots” call a “hanger queen”. It only has 100000+ miles and allthow need brakes/axles/and seats, it is realy in good shape. I am not fighting some nightmare where some knuckelhead has twisted and pryed while useing the “hillbilly picturebook” of you can fix it.
Have a MERRY CHRISTMAS and thanks to all for helping me spend my time in the air and upside down.
walka