[89 and 90 GT's]

Hello,
My 86 carbed wagon with 43K recently began having issues starting. Normally it fires up immediately. Now I can only get it to start by pouring gas in the carb. Once its running, it can be driven without issues and also idles perfectly. I let it sit overnight and now it will not start.
Can the mechanical fuel pump be weak enough that it doesn't provide enough fuel during cranking, but then once the engine is running, it is able to supply enough fuel to drive normally?
Or could it be a carb issue in that once the vehicle has been sitting for a while the residual fuel in the carb has drained out?
Any help is appreciated.
Thanks!

 

[denisond3]

Your symptoms sound very familiar. Unless you have replaced the original carburetor in the last 5 to 10 years, I would say this is mostly a carburetor problem; made slightly worse by a partly clogged pick up sock in the fuel tank. Any carburetor will have gotten some clogging from the varnish-like residue of gas (and the fine silt that is small enough to get through a fuel filter) while the car was un-used and that is now lying in the tiny passages in the carburetor that percolates air with the fuel just before it gets sucked through the venturi, plus a likely weakening of the spring or bimetal actuator that pulls the choke shut when sitting atop a cold engine. A carburetor rebuilt by a good firm (but probably not one having the lowest price) should help In some cases converting to a manual choke might eliminate the problem; I.E. installing an aftermarket cable hanging below the dashboard that you operate when first starting each morning. How well this works depends on getting the end of the cable attached to the choke plate on the carburetor, which depends on the layout of things on the side of the carb. Also a rebuilt carburetor should still have the "accelerator-pump" feature still working. This pumps a tiny squirt of fuel into the inlet when you push down on the gas pedal. It is another one of the circuits inside the carb that go bad from age, and would work better on a rebuilt carb.
Also a new fuel filter, unless you have replaced that in the last couple of years. The amount of sludge that can be pulled up from an old fuel tank is scary - like something brought up from the Titanic.

 

[LarryF]

Could be either but I'd also vote for carburetor as the most likely culprit. My '83 had starting problems and turned out to be a combination of stuck accelerator pump and a counterweight on the automatic choke that had broken off and was jamming it. I rebuilt the whole carb and it was not that difficult, although there are some interior passages that are not accessible to any physical cleaning tools. Hardest thing is getting the carb off in the first place, which is normally done with a special C-shaped box-end wrench.

 

[denisond3]

Cleaning those inaccessible interior passages is why a friend of mine bought an ultrasonic cleaner big enough to hold atcarb from a v8 engine.

 

[chrisantonellis]

where you located? I can rebuild the carburetor for you. i'd be happy to help. i'd gladly buy the wagon from you too if you're interested in selling for any reason. thanks

 

[89 and 90 GT's]

Thanks everyone for the great information! I appreciate the time that was taken to get into detail. Give me a week or so and I will post back with progress/updates. Enjoy the rest of the weekend!

 

[Joey_Twowagons]

Here's how you can check fuel delivery: first start the engine, then shut it off. Now disconnect the fuel line at the carb and direct it into a glass or clear plastic bottle.
Have someone (or you, if you can wrangle it) start the engine. You should see a heavy stream of fuel pumped into the bottle at idle. There are usually specs for this, but as a rule of thumb, if you see a thick stream it is fine.
If there is a clogged filter, faulty fuel pump etc. the fuel will just dribble out.
The carb will idle for quite some time with the fuel line disconnected, using the fuel remaining in the carburetor fuel bowl.

Oh yeah, make sure you can shut off the engine before the bottle overflows!

 

[89 and 90 GT's]

Thanks again for everyone's input. The problem ended up being the fuel pump. I figured I'd try that first since it was only $10 on RockAuto. I could be wrong, but I believe that the pump was losing prime after sitting for a period of time and the fuel was draining back to the tank. Like I mentioned previously, once I had started the vehicle after pouring fuel into the carb, the car ran fine as long as I left the car running or drove the car. It would also start if I shut the vehicle off, and then re-started it shortly after that. However, if I left it overnight, it wouldn't start. Regardless, the fuel pump seems to have fixed the issue. I also installed a new in-line fuel filter, so I'm sure that also helped the cause. Thanks everyone!