Weird carburetor problem

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xirdneh
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Posts: 2121
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Weird carburetor problem

Post by xirdneh »

We parked our two Tercel's facing each other so we could swap carbs
the plan was to remove good carb from my car and install in friends car that has a bad carb
while he was installing my carb in his car i was installing a newly rebuilt carb in my car
when we started both cars they did exactly the same thing
idled fine but when revved up to abt 3000 rpm and held there, the engine went "BLAHHH"
and rpm's dropped down to nothing.
we looked things over but could find nothing wrong, externally that is
we removed his carb and replaced it with another newly rebuilt carb and it worked great

so what the hell went wrong with those first two carbs?
why did my good carb suddenly became a bad carb?
what are the odds a newly rebuilt carb would do the same thing?
i've been racking my brain trying to figure this out
when i removed my good carb i tipped it over to clean off the mounting plate on bottom while there was gas in it
so i am thinking the gas had something to do with it
but the newly rebuilt carb was bone dry and i did flip it over to put some gasket compound on the bottom
so the only thing i can think of, is the flipping upside down would cause the float to press on the needle
could the needle be damaged doing that?
i removed the top of both carbs and could see nothing amiss inside the carb
needles looked ok but looks could be decieving
i plan to reinstall my "good turned bad" carb today as soon as there is a rain break
we shall see what happens
Last edited by xirdneh on Mon Jan 29, 2018 11:41 pm, edited 1 time in total.
Love those Tercell 4x4 wagons but they sure suffer from road noise.
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Petros
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Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Weird carburetor problem

Post by Petros »

sounds like either something in the vac system either was not hooked up after the swap, or perhaps inadvertently got damaged during the swap. Or perhaps one or more of the vac lines got installed in the wrong place. I know you should know better, but it will not hurt to double check all of the vac line routing.

Also, I doubt turning the carb over would cause that (of course, if it was full of rust and deposits, anything could happen if it came loose, but it would not likely be a good running carb than either), I have turned carbs upside down lots of times and reinstalled them with not ill effects (when I replace the head gasket I leave the carb/intake/exhaust manifold and flip the head assembly to clean the gasket face, fuel always leaks out but it always has started and ran without issues).

If you installed a factory rebuilt carb, that is likely suspect itself. I have seen about half of them behave worse than the dirty one it replaced.

keep look, you will find the mistake. chances are it was something you did, and/or somethign with the new (unknown) carb, during the swap.

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)
xirdneh
Highest Ranking Member
Posts: 2121
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Weird carburetor problem

Post by xirdneh »

i installed the the good carb gone bad back into my car and it works great
i still have no idea what caused the problem

i rebuilt the carbs with rockauto kits
Love those Tercell 4x4 wagons but they sure suffer from road noise.
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