L18 Firing Order/Spark Wire Hookup?

[banzai510(hainz)]

sooner you get a weber DGV the sooner youll be set Free!!!!!!!!!

 

I could never rebuild a stock carb. just to many small things in them

[atkinson40]

From all I can tell the carb on a "72 DAT PU is a DAH328 PN 10-115. I've removed mine and it has no ID marks on it anywhere. At least now I can go to Autozone and get the rebuild kit. It's $18. I don't know what the cleaner will cost, but a new Hitachi or Weber is over $200. I'll gamble I can pull it apart, clean and rebuild it. I've heard the doom and gloom stories from the SD carb rebuilders that I won't be able to do it, but I'm going to give it a shot. I'll be carefull, take a bunch of pictures to try and get it back together OK. Wish me Luck:) Kevin

[yello620]

LUCK:lol:

 

Spend the $18 on a Weber. The Hitachi will only give you grief. I have always been told to run the Hitachi until it doesnt run good anymore, then get a Weber. I have never seen a rebuilt Hitachi that ran right.

[atkinson40]

LUCK:lol:

 

Spend the $18 on a Weber. The Hitachi will only give you grief. I have always been told to run the Hitachi until it doesnt run good anymore, then get a Weber. I have never seen a rebuilt Hitachi that ran right.

 

You may be right, but money is dictating my choices.:( I got lots of time and very little money. If I fuck it up, I'll go the weber route, or maybe will anyway once I get the bucks. You're right, Luck :lol:

[atkinson40]

Ordered the carb kit and bought the carb dip. Disassembled the carb. My office stinks. :eek:

 

 

Two obvious problems are a couple of jets plugged. I'm not sure what they are, but I imagine they need to be open for the truck to run right.:rolleyes:

 

 

 

I'm soaking the lower body. I can begin some reassembly tommorrow and then wait on the rebuild kit.

[datsunaholic]

Um, yeah, having a plugged primary main jet wouldn't make it run very well... They do that when they sit with E15 fuel in them.

[atkinson40]

During disassembly a mystery ball showed up around the time I removed the accelerator pump. Can anyone confirm this goes trapped in the jet below the large spring below the accelerator pump plunger?

 

First I split the top off.

 

 

Then I removed the accelerator pump.

 

 

Then in removing the base...WTF is that??:lol: A little ball that I didn't have a clue where it came from. Exploded diagrams show a ball in the bottom of the accelerator pump. I'm thinking maybe as I turned the carb over it fell out.

 

 

Thanks kevin

[Cuts metal like mad]

I rebuilt one of these (just because I was bored), and found that same little thing... except it went bouncing off into 'who knows where', put the carb back together and it ran great (previously was a non runner).

 

*your results may vary*

[atkinson40]

I rebuilt one of these (just because I was bored), and found that same little thing... except it went bouncing off into 'who knows where', put the carb back together and it ran great (previously was a non runner).

 

*your results may vary*

 

I can see a spot it might fit down in the bottom of the pump well. Looks like a jet almost, but it looks to be machined into the housing. At first I thought it couldn't be, because the plunger would suck it up and dislodge it. Then I discovered the big spring has a crossbar on the bottom that fits into the well top that would hold it in. Thanks Kevin

[atkinson40]

Got the carb back on this morning. Bowl filled right up, strong stream going down the throat as I work the accelerator, but truck still won't start. I'm back to looking at electrical. In my mind I've eliminated the compression as being a problem because this truck did start and run strong at high RPMs since I've done the HG and rings. The only problem was it wouldn't idle. I'm glad I rebuilt the carb. It was a mess of corrosion and plugged jets. It would have left me stranded sooner or later. Now I OWN that carb. The carb problems would account for its refusal to idle. Maybe somewhere there's a poor connection to the coil not allowing it to develop enough spark to fire the cylinders. I do have enough to trigger the timing light on all cylinders, but maybe not enough to fire them. :blink:

[atkinson40]

Can anyone tell me where the distributor relay is physically located? I've noticed that I don't have headlights anymore and wonder if that may be connected to my not starting problem? Both have a black wire in common, but I don't know where the distributor relay is located to trace the black wire back to source. Thanks Kevin

 

PS: What causes the advanced points to not work while the retard points are in operation? I see the advance points are connected all the time to the coil and the retard points only when a set of conditions are meet. Now I only have an advance set of points installed. Does firing the retard set somehow negate the effect of the advance set? They seem to be hooked up all the time. Hoe would you not get a secound firing? Thanks Kevin

Edited August 28, 2009 by atkinson40

[atkinson40]

OK, I may have spoke too soon about"Owning The Carb". :o I pulled a plug wire and had my kid turn over the engine while I watched a spark jump through a screwdriver to ground. It has plenty of spark. :D Next I pulled a plug and they were dry as a bone. No gas getting to the cylinders.:( When I work the acceleratot pump I can see a healthy squirt going down the primary throat from a little tube that hangs over it. There must be another way the carb gets gas at a greater volume because that squirt isn't getting the plugs wet.:blink: Tommorrows another day. I'll study carb theory and try to figure it out.:blink:

[datzenmike]

The retard set are for reducing emissions. If possible wire up the advance set permanently.

 

I don't think there is a distributor relay, power for the coil comes from the fuse box via the ignition switch. If you mean the relay to turn the retard points on/off just remove the Blue/Yellow strip wire from the distributor and the advance set will now be unaffected.

 

The advanced set of points are always working and never shut off, it's just that when they open nothing happens because the retard set are still closed. Thus, when the retard set do open the coil fires after or late. (retard)

 

 

Do you have parking lights? If so do you have high beams?

[atkinson40]

Do you have parking lights? If so do you have high beams?

 

My twin sons are getting antsy to see this truck run.:) When ever they come over I get the 50 questions routine on what I'm doing to get it to run. Me buying this truck is bringing back memories of their 510 days.:) One of them was over last night and began fiddleing around with the fuse block and was able to get the headlights to work. Still no parking lights, but high and low beams work. I need to make a trip to the JY to see if the 620 there has a fuse block, mine seems toast.

 

I'm going to try and see why the plugs are dry when I pull them. For as long as we crank the motor trying to get it to start they should be drenched. Thanks Kevin

Edited August 28, 2009 by atkinson40

[banzai510(hainz)]

Pour gas down the carb and it should fire for sure.

 

truck you need to cha ge or add a another in line filter as the tank is in the wheel well with the filler tube and gets dirt running inside of filler tube.

 

My carb would plug up all the time(my 521). clean and 5 mins later was dirty again.

 

 

there is a realy for the 2nd set of points but dont worry about it.

 

ck the fuses and reset the fuses.

[atkinson40]

From reading, As far as I can tell the fuel circuit that should be delivering fuel during starting is the "Primary Main" circuit. The "Secondary Main" doesn't kick in until "the primary is open more than two-thirds and the manifold vacuum increases beyond a certain point."

 

Is this correct, or is the idle circuit providing the fuel durung startup? If its the "Primary Main" Then I can focus troubleshooting on that circuit.

 

The little squirting when I pump the accelerator has little to do with starting. It only works to transition between idle and main circuits when "accelerator pump squirts a small jet of fuel into the carburetor throat when the throttle plate is opened farther to allow the engine enough fuel to increase its speed to the point where the main circuit can take over"

 

Whats a little confussing is that if I pump the shit out the accelerator, it seems the accelerator pump is squirting enough gas down the throat to at least get the motor to start. If fact it does try to start, but never wholeheartedly.

 

I noticed during reassembly that the "automatic choke unloader" diaphram doesn't hold vacuum. I read this will cause it to run rough(vacuum leak), but could it cause it to not start? I 'll plug it off as a test.

 

Thanks kevin

[banzai510(hainz)]

Whats a little confussing is that if I pump the shit out the accelerator, it seems the accelerator pump is squirting enough gas down the throat to at least get the motor to start. If fact it does try to start, but never wholeheartedly.

EXACTLY. Like pouring gas in the carb.

The idle jet is at idle the idle circut. then transition to the main. I will assume the main will o this while the choke is ON.

 

Find the Hitachi box and throw it in the River.

[datzenmike]

From reading, As far as I can tell the fuel circuit that should be delivering fuel during starting is the "Primary Main" circuit. The "Secondary Main" doesn't kick in until "the primary is open more than two-thirds and the manifold vacuum increases beyond a certain point."

 

Is this correct, or is the idle circuit providing the fuel durung startup? If its the "Primary Main" Then I can focus troubleshooting on that circuit.

 

If your motor is warmed up then yes the idle circuit provides the fuel for starting. If the motor is cold the gas pedal should be depressed to set the choke. Two things happen. The accelerator pump squirts raw fuel into the carb (rich is good when cold starting) and the choke forces a rich condition which aids starting and cold running.

 

 

The little squirting when I pump the accelerator has little to do with starting. It only works to transition between idle and main circuits when "accelerator pump squirts a small jet of fuel into the carburetor throat when the throttle plate is opened farther to allow the engine enough fuel to increase its speed to the point where the main circuit can take over"

 

The accelerator pump does help enrich the mixture for cold starting, otherwise the rest is very true.

 

 

I noticed during reassembly that the "automatic choke unloader" diaphram doesn't hold vacuum. I read this will cause it to run rough(vacuum leak), but could it cause it to not start? I 'll plug it off as a test.

Thanks kevin

 

The choke unloader should not cause a vacuum leak. Vacuum is only applied to the unloader when the throttle is depressed fully. It's job is to open the choke on a cold motor so the engine can produce maximum power for emergency accelerating.

 

 

The accelerator pump should produce a strong squirt of raw fuel. On a cold motor the choke should also be on to help starting. You can have someone hold the choke closed to get it started, but keep your face away from the carb as cold starting with a lean mixture can cause a carb backfire.

 

If it still won't start it's time to check the ignition. Pull a plug wire off, fit an old plug in the end and lay on a grounded surface. Watch for a strong spark when cranking. If weak spark is suspected, clean or replace the ignition points setting them to 0.018"-0.022". Crank it over with a timing light connected and check the advance at around 10 degrees. No you don't have to remove the vacuum advance hose to the distributor on any L 18/20B motor. There isn't any vacuum present at idle. Might be a good time to check the valve lash too.

 

 

"if you have fuel and spark..... it will likely run"

Edited August 28, 2009 by datzenmike

[atkinson40]

"if you have fuel and spark..... it will likely run"

 

Last night I pulled a plug wire and stuck a screwdriver in the end and watched the spark jump to ground. Pumping the accelerator gives a strong sqiurt of gas down the venturi. I'll try watching spark on plug and check the timing later after the sun goes behind the mountain. It's friggin over 100 degrees outside right now:eek:

 

I was able to score a fuse holder at the junkyard today.:)

 

PS: Before I was not able to get the timing to under about 15 degrees BTDC. Maybe this is part of the problem.:confused: Also confussing is why the plugs are dry if I get a squirt from the accelerator pump:confused:

[datzenmike]

Takes a lot to wet them and gas evaporates. The distributor may need to be loosened and turned. There are two adjustment slots I believe. Even with 15 degrees I would think it would start. To retard you will need to turn it counter clockwise.

[Buzzbomb]

Last night I pulled a plug wire and stuck a screwdriver in the end and watched the spark jump to ground. Pumping the accelerator gives a strong sqiurt of gas down the venturi. I'll try watching spark on plug and check the timing later after the sun goes behind the mountain. It's friggin over 100 degrees outside right now:eek:

 

I was able to score a fuse holder at the junkyard today.:)

 

PS: Before I was not able to get the timing to under about 15 degrees BTDC. Maybe this is part of the problem.:confused: Also confussing is why the plugs are dry if I get a squirt from the accelerator pump:confused:

 

Pump it until the bowl is dry, and I'll guarAntee wet plugs :D I know because I've done it when I had a no start issue. My issue was a battery that was just discharged enough not to fire the engine. I bought a new battery, and it started right up. Easy to test the battery..

 

Is the choke working ok?

 

The little squirting when I pump the accelerator has little to do with starting.

 

That's not necessarily true. You have to pump the pedal to not only set the choke/fast idle, but you also have to prime the engine with gas to get it going. If your choke is working ok, you have fuel in the carb , and your ignition is ok, pump it twice, take your foot off the gas, and crank it.

Edited August 28, 2009 by Buzzbomb

[atkinson40]

Takes a lot to wet them and gas evaporates. The distributor may need to be loosened and turned. There are two adjustment slots I believe. Even with 15 degrees I would think it would start. To retard you will need to turn it counter clockwise.

 

 

Sometimes when troubleshooting I feel like a dog chasing my tail. :o Had wifey crank the engine and found the timing to be way off from when I was fiddleing with it before I rebuilt the carb. Set the timing at 10 degrees BTDC and friggin vrooooom.:) Idles smooth, not rough. May need some tweeks on the carb, but runs pretty good. Was getting dark so only had time to back off the idle screw and turn the mixture screw all the way in to see it had no effect. I may have the idle set so high still that the mixture screw isn't having an effect. Could be the mixture scew also, it looked kinda worn when I looked at it rebuilding the carb. As the engine warmed up the radiator cap made a pop and started leaking.:eek: So I called it a night. Next move is a radiator cap, figure out why the oil pan gasket is leaking, why the clutch pedal is now frozen, rebuild the brakes, and replace the fuse box. :)

 

PS: Maybe now I can trepidly claim that "I OWN THAT FRIGGIN CARB"

Edited August 29, 2009 by atkinson40