Big_Ern

I need some help with the stock nikki carb on my 12A ('83 gsl)

what would cause it to pump in too much fuel?

The car was sitting untoched for 8 months or so. Yesterday I drained the gas tank, and put in some fresh gas. I also put in new spark plugs

It fired up first crank! but ran like a bag of s**t unless the rpms were up then it was sorta okay - didn't wanna push it above 4k on a cold motor that has been sitting so long but it seemed to smooth out the higher I went. It eventually stalled out as I was playing around with the throttle after a couple mins of a really lumpy idle. Wouldn't start back up, so I left it over night

Today it fired up pretty quickly, but still a really rough idle which smoothed out as I brought the revs up. I was backing it out of the shed to see if a quick boot would clear things up and it stalled out on me. I tried to restart it, no go.

Left it sit for a few mins but I forgot to turn the key all the way off so the fuel pump was still running.

Tried to start it up a few mins later, and the the starter won't turn... sounds like its hydro'd, so I pulled the plugs and a ton of fuel pours out! So somehow, the fuel pump was flowing gas through the carb and directly into the motor

I left it sit for an hour with the plugs out, cleaned them up, turn the starter over to spit any remaining fuel out, put the plugs back in and it wont fire. Playing with the choke and throttle doesn't make much difference, but it almost catches sometimes at full throttle & choke, but not quite enough to get going.

Seems like its getting flooded and over fueled like crazy.

now its stuck 3/4 out of the storage shed sitting in the pissing rain


I'm quite mechanical (do all my own work and motor rebuilds etc) but don't know a ton about carbs, so what would be the first thing you would look at?
Anything simple I can check? Or does the carb need to be pulled and inspected/rebuilt?
My thoughts would be that the carb floats no longer float so it constantly pumps fuel in, but I'd like to hear some thoughts on a hopeful easier fix


I'm hoping I won't have to tear it completely apart because the car is stuck 3/4 out of the shed with the roof run off (no gutters) draining right into the engine bay so its not in the nicest spot to work on it in this pouring rain

tommyeflight89

iTrader: (4)

I don't think your issue is too bad.

Fuel is regulated into the carb by two float mechanisms for each side of it. The floats regulate the opening of two small needle valves at the top of each float bowl.

If the carb was pouring fuel out, one (or both) of these is stuck open or leaking. I assume you have a stock fuel system (fuel pump and return) so it is not a fuel pressure issue.

On the front and rear of the carb you will have two small sight glasses. Fuel should be about 1/2 way up these. If it over these with pump on and engine off, you have issues.


See what others say, but it sounds to be like you will need to at least take off the top of the carb and inspect the floats, bowls, and needles/seats. Not a huge job.

Also important is a proper deflooding procedure. If you can get the carb float levels to where the should be, I think you will still need to deflood the engine. Search for this procedure.

If you flooded it that much I think standard practice is an oil change also.

DivinDriver

iTrader: (15)

+ on stuck float(s) or needle(s), +1 on changing oil after an episode like that.

t_g_farrell

iTrader: (1)

Sitting for 8 months like that, the carb likely has sticky residue all through it. Minimally pull the top and soak things
with some Seafoam to clean it up and maybe unstick/unclogged things enough to run. Otherwise change the fuel
filter and get a rebuild kit and clean/rebuild the carb.

Next time it sits either run it until it dies with the pump off and/or drain the tank and run it until it dies so that there
isn't any gas left to cause a problem. Newer gas (E85) doesn't stay viable for more than a few months without
additives.

Big_Ern

Good info. Thanks guys.

I just changed the oil immediately before trying to start it and this flooding issue happened... guess I'll have to change it again once I get it moving - Doh!


And yes, its is completely stock fuel system and carb.

Big_Ern

I got it fixed quite easily last night.


I tested the fuel vent solenoid and it was still working, so must be stuck needles/floats. I lightly tapped on the two fuel line banjo bolts with a hammer and that freed them right up. Run great again!

Here's a quick video I put on instagram of it running again
Follow me @604ern

I'm sure the carb could still use a good cleaning and rebuild, but it works just fine to daily drive right now, so that can wait until I have time

DivinDriver

iTrader: (15)

XLNT - - now run some fuel-system cleaner and fresh gas thru it, to help with any deposits in the carb.

NCross

iTrader: (18)

New filter, a can of seafoam in the tank, and a light spraying inside the venturis and air horn with some carburetor cleaner will do wonders. Oh, and drive it!