General Repair Checklist for troubleshooting - Question
 

Hi,
My old pickup beater just stalled.
That is a '86 Mazda that has carburator and no computers so I think it should be simple enough to troubleshoot without calling a mechanic.

Does anyone know of a Generic Mechanic checklist for carburated engines?
I'd like to try fixing it before I spend the money on towing the truck to a shop + repairs.

I don't have any formal training but used to do some minor repairs with Dad on the old family cars.

Thanks!
-J

BAsics:

Does the engine turn over?

Yes

Is there spark?

If so, will starting fluid make the engine catch momentarily?

If so, is the fuel pump working? Loosen the tubing slightly and see if gas seeps out. If so, the oump is probably functional. Not knowing if your pump is mechanical or electric, I cannot go any further.

Are there any loose wires? Do you have an ohmmeter so you can check the coil for continuity?

Just remember you need three things for any internal combustion engine to function: Air, fuel and spark.

There are numerous sites that have good advice, but a basic book on auto maintenance/repair is advised, Haynes is a good basic book.

Unfortunately that happend to a relative that was driving the truck so I haven't had a chance to take a look.
I suspect it's ignition related cause he tried a bit of gas directly on the carburator but didn't work.

He did mention that before that, the truck was stuttering and he thought it was gas related so he put some more gas in the tank.

I'd like to check the ignition system but I can't remember how to do the proper tests or what values I should see in the voltmeter.
I can't even remeber how to check the condensor next to the points.

I hope is something obvious like points fully closed or loose wire but I'd like to be prepared and complete a more full diagnostic...

FUEL
-Smell of gas in the carb or tailpipe? Then it's ignition related, or too much fuel.
-Change the fuel filer if unknown, and write the date on it .
-Choke should be closed when cold, and fully open when warm.
-Put your hand over the carb(making a choke and pulling in more fuel). If it runs better then the mix is lean. Playing with the mixture screws is a bandaid for the the real problem

SPARK
-Check the battery using a DVOM. Should be around 12.6V after sitting a while, and around 13V just after running.
-Check the alternator output (DVOM still on the battery) at 2,000rpm. Should be around 13-14.5V.
-Battery connections and ground strap should be clean and tight.
-Unplug each wire and use a spark tester grounded against the block while cranking. All should be equally bright. Disconnect the electric fuel pump or pull the fuse first so that it doesn't flood the engine.

MISC
-Shine an infrared thermometer on each exhaust header. They should all be burning equally hot.
-Shine an infrared thermometer on the tailpipe before and after the catalitic converters. It should be 100+deg hotter after.
Rotary/Wankel engines burn dirty, so to pass federal emmisions Mazda put multiple catalytic converters on them