carb fuel level still too high

How-to's and repair secrets for your 4WD can be found here. Have a question? Ask it in here!
Post Reply
User avatar
dlb
Highest Ranking Member
Posts: 7305
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

carb fuel level still too high

Post by dlb »

I rebuilt a carb recently because the thing barely ran, and I could see the level in the carb fuel window was too full (it was just above the top of the glass so when I shook the car I could see the level come down into sight for just a second). Tested the float and it's good, adjusted the float level to the spec (rests at 9/32" from the lid of the air horn when it's inverted). Now the car starts easily and warms up nicely but once it's a bit warm it starts idling rough. I checked the fuel level and it's still in the same spot -- way too high. Don't know if the rough idle and the fuel level are related but I want to fix the fuel level first since I can see it's incorrect. So my next thought is to try adjusting the float even lower. Doesn't seem right but I can't think of why else the level would be so high. Fuel isn't blasting out of the carb on idle so I don't think the fuel pump is pushing too hard. Anyone have any ideas?
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: carb fuel level still too high

Post by Petros »

if you replaced the seat and needle valve the level has to be reset since you changed the relationship between the float and needle valve. Also, too high fuel pressure can overide the needle valve, but if you are running the stock fuel pump I doubt that is the problem, though it would not hurt to put a fuel pressure gauge on the fuel line to the carb and check it (you just need to crank the engine for 30 sec to verify fuel pressure between the pump and the carb). As I recall, it should only be 2 psi. if it is any higher you have regulate it down.

any dirt or grit you may have worked loose and is not caught in the needle valve could also cause an overfilled float bowl. if you take the top of the carb off, carefully clean out the needle valve and the valve seat to remove any grit or debris before you reset the float level. This has happened to me more than once. worked fine before I opened the carb, I would just clean it out and put it back gether without changing any parts. than I find the float leavel is too high and it is flooding. pull it out and carefully clean out the needle valve and fuel line, problem goes away.

good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
User avatar
dlb
Highest Ranking Member
Posts: 7305
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: carb fuel level still too high

Post by dlb »

Petros wrote: Sat Nov 26, 2022 12:28 am if you replaced the seat and needle valve the level has to be reset since you changed the relationship between the float and needle valve.
Thanks Peter. What do you mean by "the level has to be reset"? Should I drain the fuel out of the bowl? I assumed that would happen once the engine starts running and sucking fuel, is that incorrect?
User avatar
NWMO
Highest Ranking Member
Posts: 1615
Joined: Wed May 20, 2015 1:08 pm

Re: carb fuel level still too high

Post by NWMO »

Hey David,

It sounds like you went about things properly. If the fuel level is still too high, pop the top off the carb and adjust the float further from air horn (when inverted) so the level adjust down. I had to adjust mine a few times to get the level where desired. Based on the FU-2 Troubleshooting, I don’t expect this to solve your issue, but it should be set properly before continuing to gind the challenge.
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain
Post Reply