Hi, I wonder if you could help me diagnose this prob. My car is an 86 IROC with an LG-4 engine.

I was driving home last night when I stopped off at the supermarket close to my apartment. When I came back to the car (motor still hot) I started the car...started fine, then as I started accelerating, the car started to sputter and threaten to stall. It had done this before, but I had assumed at the time it was a timing problem, so I replaced the ignition and retimed it twice, it'd been running fine since then.

Anyway, I managed to limp the car back to my apartment and take a look under the hood. When I opened the air cleaner, there was a lot of gas going into the carb. When I put the cleaner lid back on, the car stalled. I looked again and saw puddles of gas on the primary throttle plates and a white fog (I guess gas fumes) rising out of the front bores. So I let it sit for a minute and then pushed the throttle to the floor and cranked to purge the fuel...started up, sputtered a little, then started running normally.

This morning the car starts fine, runs very nice, and shows no signs of sputter or flood.

The question is, should I still worry about this? I'm thinking it's probably a sticking float needle or the like...but I've been running winter fuel treatment and I thought that cleaned the carb. Could it be a little bit of debris got stuck in the float and the car just passed it and will run fine now? Should I worry about a recurrence? Anything else I should look at? I had the carb rebuilt last winter, could it have been poorly rebuilt?

Thanks for your help
Mark

 

I'm not sure what you mean by "winter fuel treatment", but I assume you mean a gas line antifreeze. These are typically alcohol, which obsorbs the water in the gas and runs it through the engine. It also is a solvent to the gunk that will build up in a fuel system (particularly the gas tank), which often comes off in chunks.

Most likely you picked up a piece of that or something in your needle/seat, which cleared when you did your flood-clearing routine. But, in order to get to the needle/seat, it had to get past the filter. Assuming you have only the stock filter in the carb, these are designed to by-pass when they get clogged (could also happen under high demand with a partially-clogged filter). I would recommend changing the filter.

You may have something in your float bowl now, but getting that out will require disassembly of the carb. The bottom of the bowl is lower than the pick-up points for the jets, accelerator pump, etc., so it could sit there for a long time without causing any trouble. Or, it could get sloshed into one of the areas during a hard turn, hard acceleration, or something of that sort.

If this flooding happens again, one quick way to clear the needle/seat is to remove the fuel line from the carb and plug it: Then start the engine (will probably require flooring it like you did), then let the engine run until it dies. This will empty the fuel bowl, and drop the float and needle down. Reconnect the fuel line and start it up - with the needle off the seat, the flow of fuel will clear the debris out.

If it took a year to have this problem, I doubt it had anything to do with the rebuild.

Hope this helps.

P.S.: If they use "oxygenated" gas in your area, and ethanol is the added agent, then it does you absolutely no good to buy that gas line antifreeze - it's already in there.

------------------
82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, Hooker headers & y-pipe, hi-flow cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Thanks.

It's a new filter, I changed it before, but I think it might not be working properly. I recently had to screw a self-tapping fuel inlet nut into the carb to stop a leak...the nut was longer than the stock one, so I had to expand (stretch) the spring to make sure it pressed the fuel filter into place, but maybe it isn't strong enough. I guess I should look into an in-line filter.

I don't know why it was doing it before, tho. It was misbehaving earlier this winter in the same fashion. Oh well...I'll keep an eye on it. Thanks for the tips.

Mark