setting timing -turning but not starting - Off-Road Forums & Discussion Groups

lefty915 · #1 07-22-2008, 11:30 PM

1985 cj7 258 6 cylinder
Timing was off. I followed steps to statically set timing. I manually turned engine until timing mark is set to 8 degrees before TDC. I adjusted distributor and rotor so that narrow end of rotor with metal is lined up with no. 1 plug tower on distributor cap. Also getting spark to number one plug, but still not turning over. What else can I try.

RRich · #2 07-23-2008, 02:37 AM

If it's backfiring and burping it's 180 degrees out, meaning the rotor is pointing the wrong way.

It cannot run 180 out.

You can lift the distributor up till you can turn the rotor by hand and point it 180 degrees opposite.
Or the simpler way is to move all the wires, one at a time, straight across the cap to the other side. Move them in pairs.

If it's not trying to backfire, just cranking over without any excitement, try priming it with a shot of fuel. Pour a capful or so down the throat - carb or throttle body.

Keep your face back - it could backfire and spit that burning gas back at you!

lefty915 · #3 07-26-2008, 01:41 PM

Ok, thanks for info. I am pretty sure I am at TDC on compression stroke now, but turns over strong but will not start. Tried priming the carb but only get the spitting hiss noises. Problem originally started when adjusting timing and there was a backfire. Started once after that but not anymore. Maybe time to rebuild carb. What could have happened to carb to cause this? If this is the problem.

Jim_Lou · #4 07-26-2008, 07:53 PM

If it won't run on gasoline dribbled into the carb, you have a problem other than carb.

What steps did you take to make sure the timing is right? You only mentioned pointing the #1 terminal on the cap to the tip of rotor. You can still be too far off for it to run. If you have an electronic distributor you'll need a timing light to get it right. However you can get it close enough to run by rotating the housing in about 1/8" inch steps until it fires. Once it's running, rotate it back and forth until it runs the best and you'll be pretty close.

lefty915 · #5 07-27-2008, 05:00 PM

Pretty sure I am now on compression stroke now. I tried both positions by manually turning engine to 8 degrees before TDC and lining rotor up with no. 1 plug tower on rotor cap. Tried to start it. Nothing, so I manually turned engine again to 8 deg BTDC until the rotor was facing 180 degrees opposite of no. 1. Then removed distributor clamp, raised it and turned rotor 180 until lined up with no.1. Tightened everything and tried to start it again. Again nothing. Also noticed that when I manually pull back throttle linkage a couple times I do not see gas spurting into throttle body. It used to squirt from the two jets.

Maybe ignition module went out?

RRich · #6 07-27-2008, 05:50 PM

Ignition module won't stop fuel flow.

Out of gas? (Duh, more than once I've ---)

Bad fuel pump, clogged filter? Disconnect carb inlet to see if it's getting fuel pressure.

It could be just that the pump is dry - leather shrinks.

Try priming it with a tablespoon or two of fuel. Keep your face away - in case NOW it's 180 out.

lefty915 · #7 07-27-2008, 06:46 PM

Ok now I am 99% sure timing is set right since it will start and not back fire. Latest update. Now if I prime carb it will run for about 10-15 seconds and die. Also noticed that when I manually pull back throttle linkage a couple times I do not see gas spurting into throttle body. It used to squirt from the two jets.

Maybe fuel pump is out or jets clogged?

RRich · #8 07-27-2008, 08:04 PM

That's a good start. Now it's a case of why no fuel is getting to the carb.
More than likely it's not in the carb, if it was a problem with the accelerator pump, it should have kept on running.

Look for an external reason.

lefty915 · #9 07-30-2008, 10:03 PM

Probably a dumb question but I'm learning. I disconnected fuel line at the fuel filter, primed carb, started it and observed that no fuel was being pumped out of line. I assume this means the fuel pump is bad. But I won't to be sure before I replace fuel pump.

jdoggmoney · #10 07-30-2008, 11:46 PM

Remove the fuel line before it gets to the filter. Place the fuel line into a 20oz pop bottle and place the bottle so it will not fall or tip over. You don't need to prime the engine at this point. You've run it enough that the pump should be primed from the tank. Just crank the engine over while watching the flow into the bottle if posssible. You should get pulses of a strong full stream of fuel into the bottle. There is a spec, but I would say that the pump should fill the 20oz bottle to 1/2 or 3/4 full in that amount of cranking time.

If you can't see the bottle as you crank, you should be able to get a good idea of volume with the result.

Now... If the pump is not getting enough fuel to the carb, it's a good idea to go ahead and inspect the tank and fuel lines from the tank to the pump. The tank could be rusty, causing the pump to clog. If this is the case, a new pump won't last long. Also, a small hole in the hard or soft fuel line could mean the pump I sucking air from the hole instead of fuel from the tank. Check and replace whatever looks suspect. I would even go as far as to cap one end and fill the entire length with compressed air. You will be able to hear any leaks.

Drop the tank (It really isn't that difficult unless it's plum full), pull the sender unit and visually inspect the fuel pickup and interior surfaces of the tank. Could be the pickup tub is clogged or even broken off. ONE IMPORTANT NOTE HERE: When you are removing and re-installing the locking ring for the sender, use a BRASS punch. This will help avoid any unwanted sparks that could end your project (and life) in a hurry.

Having said all of this.... if your fuel pump passes the cranking/volume test, there's only one thing between your point of the test and the carb.. the filter... or the carb itself is not allowing the fuel in.