Engine hesitation (1 Viewer)

[69FJ40HILIX]

Still waiting on parts, but it occured to me that I could run the compression test since the coil isn't working. #1 - 112lbs, #2 (this one was the one with the stuck valve) - 100lbs, #3 - 110lbs, #4 - 116lbs, #5 - 111, #6 - 108lbs.
Edit...I just read Solice in Solitudes post (#2 - Compression test 2f confused), and realized I didn't do the test correctly. Didn't warm up the motor or remove all the spark plugs...I need to redo it I think.

When you run the test on each cylinder spin the motor over at least 5 times. after you have run the test for all cylinders go back and test again but squirt a small amount of oil in each cylinder (1/4 teaspoon) and check again. This is done to check leakage around your rings.
Second ; if you changed from points to electronic distributor the coil is different for each type, make sure you have the correct coil.
Third; Once the engine is running take a propane torch (do not light it) and turn it on low gas and place the end of the torch all around your carb including the base. If the motor revs up you have a leak sucking air at that part (base gasket etc.) and it sucks in the propane which revs up the motor. You can test all vacume hoses this way including at the distributor if vacume advance.
Fourth; If the truck sat that long you need to check the auto advance weights in the distributor to make sure they are free and move easily when the distributor spins.
Last; On the carb check to see if the primary pump is working correctly (turn throddle linkage and see if it squirts gas into carb throat) . If this pump seal is dry it will do what you say yours does, coughs through the throat bc it is sucking air/gas.

 

[Groucho263]

When you run the test on each cylinder spin the motor over at least 5 times. after you have run the test for all cylinders go back and test again but squirt a small amount of oil in each cylinder (1/4 teaspoon) and check again. This is done to check leakage around your rings.
Second ; if you changed from points to electronic distributor the coil is different for each type, make sure you have the correct coil.
Third; Once the engine is running take a propane torch (do not light it) and turn it on low gas and place the end of the torch all around your carb including the base. If the motor revs up you have a leak sucking air at that part (base gasket etc.) and it sucks in the propane which revs up the motor. You can test all vacume hoses this way including at the distributor if vacume advance.
Fourth; If the truck sat that long you need to check the auto advance weights in the distributor to make sure they are free and move easily when the distributor spins.
Last; On the carb check to see if the primary pump is working correctly (turn throddle linkage and see if it squirts gas into carb throat) . If this pump seal is dry it will do what you say yours does, coughs through the throat bc it is sucking air/gas.

@69FJ40HILIX this is amazing info. Thank you. Here are some answers:
- When I had the head off to replace the head gasket, the rings were checked and were good.
- I'm back to points and an FJ60 coil/dizzy. The electronic ignition failed 2 times...even when Petronix said that was impossible. Well...they did so I put points back in (new points).
- I will do the propane test...haven't done that. I'm waiting on gaskets for the carb now. After I put those on, I will check. Not sure what other vacume hoses there are? I don't have a clamp on the hose going from the dizzy to the carb...does that need to be clamped to prevent leaks?
- I replaced the dizzy and spent waaaaayy too much time on that whole thing. It works great now.
- I will check the primary pump...but think I did that a while back and it was working. I'll double check.

While I wait on the gaskets to get here, I am not sure what else to do. But...when it idles, the amps go back and forth (see video). Would this suggest a loose ground?

 

[Groucho263]

Anybody have any thoughts on the amps bouncing around like that?

 

[fjc-man]

Running, is the voltage at the battery fluctuating like that, as well?

 

[Groucho263]

Running, is the voltage at the battery fluctuating like that, as well?

Let me check and report back.

So now of course I can’t replicate. At the battery, it stays constant amps and for the first 5 min was around 16v. I turned it off then started again to see if it would do it and volts were 13.7…so battery was charging? Amps stayed constant at the battery and on the gauge.

When I took that video originally, the truck was on a decline nose low on the driveway. Not a major decline but I’ll have to try to reproduce tomorrow.

Here is what I can’t figure out. Can a short cause this? Before I had the power steering done, I didn’t have this problem. I will have to ask, but assume they took off the left front quarter panel to do the fabrication. After I got the truck back, I noticed reverse lights don’t work. Maybe there are some loose wires now?

So, when I get the carb gaskets I’ll see if that helps. If that doesn’t do anything, I’ll have to check the whole truck for loose wiring.

 

[Gretchet]

Let me check and report back.

So now of course I can’t replicate. At the battery, it stays constant amps and for the first 5 min was around 16v. I turned it off then started again to see if it would do it and volts were 13.7…so battery was charging? Amps stayed constant at the battery and on the gauge.

When I took that video originally, the truck was on a decline nose low on the driveway. Not a major decline but I’ll have to try to reproduce tomorrow.

Here is what I can’t figure out. Can a short cause this? Before I had the power steering done, I didn’t have this problem. I will have to ask, but assume they took off the left front quarter panel to do the fabrication. After I got the truck back, I noticed reverse lights don’t work. Maybe there are some loose wires now?

So, when I get the carb gaskets I’ll see if that helps. If that doesn’t do anything, I’ll have to check the whole truck for loose wiring.

I'm getting frustrated for you as I read this thread! You'll get it figured out. You are in the midst of geniuses! Best of luck,

 

[Groucho263]

Well...I'll probably shoot myself in the foot with this...but I think I got it. Carburetor gaskets...both of them. The old one I had on there crumbled off...it had to be causing a vac leak when the motor heated up...I hope.

I have driven it most of the weekend and so far...

 

[Groucho263]

Still working...

 

[Groucho263]

And s***. Not working. Same issue. So frustrating. Basically driving in 4th gear steady rpm and the engine acts like it’s running out of fuel. It stutters and if I keep the gas pedal steady it will chug and eventually stall. Before the carb gaskets, the engine would die. Now it doesn’t die when I lift off the gas and out the clutch in and coast. If I keep driving it eventually happens in 3rd then 2nd gear.

Can anybody tell me what the carb site window fuel level should be with steady rpm increase. Mine at idle is halfway in the window. As I add rpm, that level drops to the bottom of the window and actually below. Is that normal behavior?

I have another carb I can try but maybe it needs more fuel? I have a new engine driven fuel pump on there, and from the PO an electric fuel pump that I disconnected. I can try to reconnect and see.

I’m about to drive this thing off a bridge.

 

[Groucho263]

Fuel delivery...I'm pretty sure the fuel filter isn't supposed to look like this. I thought this fuel tank was pretty new...but maybe it sat in a field with the rest of the truck.

Just test drove with clean filter...appears to have solved the issue...for now.

 

[Cromagnon]

I think you know that this is going to continue until you clean the tank out. I would keep a spare clean filter handy until you do... might keep the truck from going over a bridge.

 

[Groucho263]

I knew right as soon as I saw that filter...but am choosing to stick my head in the sand for the time being. I'm going to have to find time to pull the tank and clean it in the near future...(I ordered a couple more spare filters today).

 

[Groucho263]

Quick update for anybody following with the same issues. Ended up pulling the tank and using this product to seal my tank: KBS Tank Sealer System - All-Inclusive Tank Liner Kit - https://www.kbs-coatings.com/kbs-tank-sealer-system.html

I guess I could have bought a new tank, but that was close to $500 and this is about $75. It was a couple day process (4-5 days)...but so far so good. Clean filter and the truck is running great.

 

[Groucho263]

Guys...need some help with this carb. It started acting up again...and I was thinking thinking there is leftover crap from the gas tank (before I sealed it) in the carb. It's a City Racer carb...and I pulled that white crap from the inlet and can see the screen has some crap on it...but I can't get to it. Do I unscrew the gold part (does that unscrew?) and pull the screen out?

 

[69FJ40HILIX]

The part you pictured is the needle seat for the incoming fuel, the float pivots on those two holes and holds the float needle & wire keeper to shut off the incomin gas when the float is level to the carb body. Yes you can unscre it just beware of the neelde seat at the bottom of it, dont scar it or the needle won't seat all the way. Have you tried to just use a air gun (the ones with a rubber tip) to bow the sediment out ?? You can use a dental pic to loosen the material then blow it out. The other small one with a hole is a jet and it can be unscrewed also to check for sediment. When you reinstall the float make sure it hangs on the float wire keeper and not just sitting in the hole, when installed it should be level to the body of the carb in the position as you have pictured it. You adjust the float by slightly bending the tab on the float that is pushing against the needle when installed. Hope that helps

 

[Groucho263]

@69FJ40HILIX thank you so much for this info. I think I understand.
In the top picture, in the top left corner, there is a brass fitting right next to the float hangar. I think that is the jet you are talking about that can be unscrewed. That is what I think I need to unscrew to make sure there isn't any more sediment in there.
The mesh screen is a little out of place...will that come out when I unscrew the jet? I'm assuming I take a larger flat head and unscrew it. (I have the needle out and set aside). Is there another needle in there after I remove the jet?
If the wire mesh doesn't come out...I think I can reposition with a dental tool.
On this carb, I had to adjust the float to get the fuel level in the site glass in the middle...so I was previously able to adjust that float.

 

[69FJ40HILIX]

@69FJ40HILIX thank you so much for this info. I think I understand.
In the top picture, in the top left corner, there is a brass fitting right next to the float hangar. I think that is the jet you are talking about that can be unscrewed. That is what I think I need to unscrew to make sure there isn't any more sediment in there.
The mesh screen is a little out of place...will that come out when I unscrew the jet? I'm assuming I take a larger flat head and unscrew it. (I have the needle out and set aside). Is there another needle in there after I remove the jet?
If the wire mesh doesn't come out...I think I can reposition with a dental tool.
On this carb, I had to adjust the float to get the fuel level in the site glass in the middle...so I was previously able to adjust that float.

That larger brass fitting next to the float mount is the float seat. The jet is the smaller one down and to the right of the plunger. Both can be unscrewed out of the carb body and I would check both for trash and see if the jet is clear. The jet has pin holes in it to regulate the volume of gas entering the throttle chamber (throat of the carb where gas and air get mixed before entering the engine). I could't really see exactly what was inside from your picture. If the screen moves around it will restrict the flow of gas entering the fuel bowl. I would remove it and install a sediment bowl with filter in the fuel line before it enters the carb. An inline filter works but I like to see if trash is coming in from the tank, if it is it ends up in the sediment bowl (my preference but either will work). Those screens have very little surface area so without a filter it will plug up quick, that's why I run a bowl instead, that filter has a lot more area to keep the fuel flowing clean. Enjoy.

 

[Groucho263]

This is perfect. I am going to be working it this weekend let you know how it goes. Thank you!

 

[Groucho263]

I can't get the float seat unscrewed. It's in there tight and I don't want to mar the brass...Any flathead I have isn't wide enough at the base...and I just want to make sure that thing unscrews before I get a screw driver and wrench on it.
I got the jet out easy and made sure that was clear with compressed air.
And are you saying to take that little screen out of there?

 

[69FJ40HILIX]

I can't get the float seat unscrewed. It's in there tight and I don't want to mar the brass...Any flathead I have isn't wide enough at the base...and I just want to make sure that thing unscrews before I get a screw driver and wrench on it.
I got the jet out easy and made sure that was clear with compressed air.
And are you saying to take that little screen out of there?

(#1) If it is floating around and not secure I would remove it, if not leave it but use a filter before the carb.

Common sense says the slots are there for a reason on the needle valve seat. If you don't have anything between the fuel coming into the carb other than the screen then see #1.

You don't need to remove it if it is clear of debris, save the time and don't remove it.