Engine juddery, loss of horsepower.

[None_zero]

@datzenmikeok I got you. It seems to be doing OK it idles and drives pretty good. But i hear what i would describe as a high-pitched sound of air being sucked in. Could just be the intake i guess. I do have one other question regarding the tachometer... if at some point previous my curiosity had gotten the better of me and I took the gauge cluster apart could I have done something retarded like remove the indicator needle So I could remove the face of the tach and look at the mechanism and put it back on in the wrong position.... or what I've just done jacking with it break the indicator needle..... Son of a bitch  

[None_zero]

20 minutes ago, None_zero said:

@datzenmikeok I got you. It seems to be doing OK it idles and drives pretty good. But i hear what i would describe as a high-pitched sound of air being sucked in. Could just be the intake i guess. I do have one other question regarding the tachometer... if at some point previous my curiosity had gotten the better of me and I took the gauge cluster apart could I have done something retarded like remove the indicator needle So I could remove the face of the tach and look at the mechanism and put it back on in the wrong position.... or what I've just done jacking with it break the indicator needle..... Son of a bitch  

Because now that I have broken the needle I see there is a small Crack all the way down it that looks like maybe I already broke it once (double dummy) and glued it back on, Or something ...maybe one day I'll learn not to mess with things but it's not a bet I'd make at the bookie---- the more I think about it, I'm pretty sure I remember breaking that tach needle and gluing it back on the spindle.... I always underestimate how brittle the little plastic bits have become on this truck, I've snapped the little tabs off just about every quick connect in the thing

Edited March 2, 2023 by None_zero

[None_zero]

Also I still can't account for the poor gas mileage, I haven't been checking the exact consumption every trip but initially it looked like I'd jumped from 9mpg to about 13mpg (still very low in my estimation) but then on the trip home that next day it was back closer to 9mpg again and I don't know if that's due to the plugs fouling back up after cleaning or what. I plan to check them this evening as it's been a couple days now since I pulled all the plugs and cleaned them and cleaned the carburetor and the distributor contacts so I'll check all that again tonight to see if they have fouled back up or if it must be something else 

[None_zero]

So back on this a bit. Idle mix screw still seems to give best idle when closed completely. All in all its been running really decent the last week or so. However today I stopped before heading home from work and put about $15 in 100%pure gasoline. As I was pumping it into the tank I leaned over and whispered "remember the good old days?" Anyway headed home and made another stop near the end of the trip. Now I've been starting the truck with no gas pedal use. Just flip on the fuel pump and wait a couple seconds then bump the switch one time and boom she fires right up. But at this last stop I had to floor the pedal and hold it to get the engine to catch and even once it did and I could let go of the starter switch I had to keep the accelerator floored for a solid 10-20 Secs before it took off and started to rev. Why would it do that? Just being ornery because she realized how much corn gas she's had to choke down?

[datzenmike]

The carburetor has what? a half cup of gasoline in it. You would have started with the original gas and it would take a while to use the gasoline that was in the carburetor and push all the original gasoline out of the fuel line to get to the new. So no, not the new gasoline.

[None_zero]

2 hours ago, datzenmike said:

The carburetor has what? a half cup of gasoline in it. You would have started with the original gas and it would take a while to use the gasoline that was in the carburetor and push all the original gasoline out of the fuel line to get to the new. So no, not the new gasoline.

No I drove about 17 miles after getting the gas before i stopped the last time 

Edited March 11, 2023 by None_zero

[Stoffregen Motorsports]

Engine idles best with the idle screw closed all the way indicates two things.

 

1 - throttle plates open too far (idle screw too far in)

2 - clogged jet somewhere

 

May be time to remove the carb and take it apart to clean it. Or at least remove the jets and blow through them with air and/or carb cleaner. Just don't blow air into the accelerator pump cavity. Too much air pressure in there could destroy the diaphragm.

[datzenmike]

 

 

What's the idle speed?

 

If 1,000 or more then the throttle plate is not closed enough and the idle mixture won't have much effect. 

 

Other excessive idle speed causes...

1/ the secondary is not fully closed. Had this, doesn't take much to get something jammed in the throttle plate.

2/ the BCDD is not turning off. Turn adjustment screw counter clockwise 1 or 2 turns to dial back the sensitivity.

 

Idle is normal, about 700 then idle mixture screw may have been over tightened at some time and damaged the screw and or the carburetor and fuel cannot be shut off. Easy enough to swap the damaged carburetor base with another.

[None_zero]

Yeah if gauge is reading accurately now which I believe it is because I was on the Interstate today doing 70 in 4th at 3500 rpms and I think I remember that's how it used to be. Then the idle rpm is at 1k but if I try to lower it then the truck dies and the timing retards so far that I can't bring it back to 5° anymore because I've maxed out the adjustment 

[datzenmike]

You'll never get the timing right with a 1,000 RPM idle. Anywhere above 750-800 the centrifugal (mechanical) advance starts being added to the static timing.

 

Get the idle down closer to 650-700.

[None_zero]

2 hours ago, datzenmike said:

You'll never get the timing right with a 1,000 RPM idle. Anywhere above 750-800 the centrifugal (mechanical) advance starts being added to the static timing.

 

Get the idle down closer to 650-700.

Ok so if the engine stalls at that rpm, I'm back at square 1 hunting more vacuum leaks?

[None_zero]

21 hours ago, datzenmike said:

You'll never get the timing right with a 1,000 RPM idle. Anywhere above 750-800 the centrifugal (mechanical) advance starts being added to the static timing.

 

Get the idle down closer to 650-700.

Somethings gotta be wrong then right if I'm maxed out on my timing adjustment and ime having to get the distributor to advance it mechanically to hit the 5° or am I thinking of that wrong? Maybe I missed by more than a tooth when installing the oil pump spindle ?

Edited March 12, 2023 by None_zero

[datzenmike]

Is vacuum advance disconnected?????? Disconnect in case this is altering the timing. 

 

Set to TDC and lift distributor out. If you should see 11:25 distributor is timed correct.

 

 

Won't idle at 700 then no gas getting to the idle circuit. Try turning idle mix screw out to make richer.

[None_zero]

Yes vac advance still disconnected. I'll check the spindle position after work today 

[None_zero]

14 hours ago, datzenmike said:

Is vacuum advance disconnected?????? Disconnect in case this is altering the timing. 

 

Set to TDC and lift distributor out. If you should see 11:25 distributor is timed correct.

 

 

Won't idle at 700 then no gas getting to the idle circuit. Try turning idle mix screw out to make richer.

If I turn the idle screw out it only gets worse. Right now the fast idle screw is turned in raising the rpms so that it will idle but at higher than normal idle speed but even with that this morning while I was warming it up it idled for about 10 mins and then slowly idled down until it died. I restarted it and it idled till I took off in it after that. Maybe another 10 mins or so. I should clarify here since I'm talking about two different adjustments at the same time moving the idle mix screw out worsens the condition and it is all the way in or maybe a half turn from all the way in. I've turned the fast idle screw in as well to compensate 

Edited March 13, 2023 by None_zero

[None_zero]

One more thing. Am I looking for compression stroke or just cylinder one at the peak of its cycle 

[datzenmike]

There are two TDCs. One is at the end of the compression stroke, up to TDC and one is the exhaust stroke. You want the Compression stroke where both intake and exhaust valves are closed. On the exhaust stroke, the exhaust will almost be closed and the intake starting to open.

[None_zero]

Damn so I can't just put the timing mark on zero huh? Nothings ever easy

[None_zero]

@datzenmikeso when the timing mark is at zero I will either be at tdc compression, Or tdc exhaust right? Because I set the timing mark at zero and opened the rocker cover and what I see is not as described in your above post. What I see is... cylinder one closed (intake and exhaust) cylinder 2 exhaust nearing the apex of the lobe intake closed, cylinder 3 intake nearing the apex of the lobe exhaust closed cylinder 4 intake and exhaust at the beginning of the lobe.... I'm confused but i.do have the two lobes on Cylinder one pointing like a downward v (upside down v) so that should be the compression stroke right?

Edited March 13, 2023 by None_zero

[None_zero]

9 hours ago, datzenmike said:

There are two TDCs. One is at the end of the compression stroke, up to TDC and one is the exhaust stroke. You want the Compression stroke where both intake and exhaust valves are closed. On the exhaust stroke, the exhaust will almost be closed and the intake starting to open.

Ooooooookay I think I get it now. The intake and exhaust.....ON CYLINDER ONE. not the intake and exhaust as in all of them 

[datzenmike]

The number one cylinder.

[None_zero]

So here is a question that I can't seem to find in the fsm...when removing the distributor. To see what you've shown I. The pic should I remove the bolts from the adjustment plate and remove from there or the bolts mounting the support in Place below that?

[None_zero]

Or would I need to disassemble the whole thing piece by piece as described in the back of the fsm (I did finally find it)

[datzenmike]

Remove the bottom two bolts that go down into the timing cover. This will preserve the ignition timing and it cab be put back in the exact same position. The distributor cannot be put back in wrong.

[None_zero]

So yeah I think it's backwards and my picture looks different from yours.... or rather not backwards but canted the wrong way. 

Edited March 19, 2023 by None_zero