Engine running rich

[droptop73]

I'm running a .032" gap with my MSD and Duraspark distributor.

 

[mchandford]

I'm running a .032" gap with my MSD and Duraspark distributor.

Ok, I am going to try changing plugs and go back to the .035. I am also going to change the rod springs to a lighter one.

I don't have compressed air to blow through the idle air screw holes, but what about carb cleaner? Is it a bad idea to put that stuff directly into the carb? I think I may end up just taking the whole thing off and cleaning everything. Seems pretty easy and I think it is overdue.

 

[marks73]

A rebuild gives you 2 opportunities. #1. You know for a fact that everything is clean and clear. #2 Great experience for when you start dialing it in for max performance.

 

[mchandford]

So I pulled the carb off today. Pretty simple. Got it home, got some carb cleaner before the auto store closed but they did not have the right kit for me.

As I was taking it apart I thought I had found a major symptom to come ask you guys about, but I figured out I had hit the accel pump as I was taking the clips out and squirted fuel down the intake.



Anyway. Got it back home and taken apart, slowly. tried to take lots of mental notes and keep all the parts in order in a tray. It all looked really clean, nothing really out of place, or loose, and didn't see any 'gunk'.

I do think I found something off.



This is in the secondary circuit, I believe this cavity is where the weights for the secondary circuit hang out. Sorry not sure of the exact nomenclature. Either way, I am not sure if there should be fuel hanging out in here or not. And even if there is the fuel that is in there is the wrong color and seemed thicker than it should have been. I am thinking that maybe this is fuel that has made it in there due to my rich condition, but not sure how or why.

I also decided I am going to change the accel pump position. It was in the middle slot, I think I am going to go to the nearest slot. I am fairly certain this is the correct position to give me a shorter/smaller shot of gas. After I got the carb off i was playing with the pump and it seemed that every time I pulled the accelerator it squirted an awful lot of gas. So I'm going to try a smaller squirt.

I will be getting rebuild kit and changing needles, and if I can figure out how to get them off, the seats as well. Both gaskets, and anything else I can replace that seems important. I will still need to get it back on the car and test it out.

 

[Mikes73]

The fuel you are seeing there is normal, I thought the slot closest to the carb body gave the biggest shot of fuel on the pump.

 

[mchandford]

The fuel you are seeing there is normal, I thought the slot closest to the carb body gave the biggest shot of fuel on the pump.

Anyone have any for-sure guidance on the accelerator pump positions? It looks like the one closest only pushes the pump half as much as the furthest position.

And what is the procedure for checking fuel pressure? it seems like I should need a T fitting and an pressure gage. But what are you guys doing to test pressure?

 

[marks73]

The fuel you are seeing there is normal, I thought the slot closest to the carb body gave the biggest shot of fuel on the pump.

Anyone have any for-sure guidance on the accelerator pump positions? It looks like the one closest only pushes the pump half as much as the furthest position.

And what is the procedure for checking fuel pressure? it seems like I should need a T fitting and an pressure gage. But what are you guys doing to test pressure?

That's exactly what you would need to check pressure. Great way to check your pump quickly.

 

[mchandford]

Got the correct kit for the rebuild. As I was researching parts, and the kit I needed the kit instructions mentioned a brass weight and check ball. I remember the brass weight, but what check ball? I went back to the garage where I was working and looked around, but I remember very well that I flipped the carb to get the brass weight out, it went right in my hand and I am 99.999% sure I did not drop a metal ball. So that may have been part of the problem with the carb. I got everything back together, new needles and seats, cleaned all the passages and the outside as well.

I picked up a 1" carb spacer from the parts store, but the carb studs were too short, so that will have to wait. I got everything put back together, took my time, and double checked all the connections. I think I did a pretty good job getting it together. So i get in the car, crank her over a couple times to fill the float bowls. tap the gas once, crank it over and...

it fires up!!!

but there is a TERRIBLE noise!

WTF? shut it off as fast as I can, jump out, stare at the thing for a second before :idea:

***FACEPALM***

While the carb was out I had the idea to check spark plugs. But I hadn't gotten around to them all. Only one. I had taken it out, checked the gap and cleaned it up. But never put it back in. DOH!

Anyhoo, put the plug back in wires on, double check the others, and good to go.

Take 2! Cranked her over and she fired right and sounded pretty good. IT was running smoother than before, but was still off. I knew that though, needed to adjust air screws and timing again. I let it warm up, and it was still sounding pretty good. Before I had touched anything but giving a little gas, the choke was off and it was idling pretty smoothly, at around 650. First time it has idled that low. adjusted air screws, not much change when I took them out more than the 1 1/2 turns from closed. but the idle got smoother and a 1/2 inch vacuum increase when I took it to 3/4 turns from all the way in? WTF? So I think, lets adjust timing. I was only at about 15 in vacuum where the timing was at, so this is a big change from before the carb cleaning, but not sure why.

So I started by moving the distributor clockwise, advancing the timing. I got the vacuum up to around 18 and backed it off a bit to around 17, it sounded good, but the idle had come up to around 950. hmm, slow the idle down a bit, but when I hit the gas and let off it stumbles before catching itself. hmmm, back to around 850? sounds ok, and doesn't stumble when I let off the gas, ok. shut the car off to check something, went to start it back up and it would just click-click. dang too much timing. so come back some, started back up, still have 17 vacuum, still at 850 idle. Cool. I decided to pull the plug off the vacuum advance port with it running, no vacuum there at idle so no prob. reconnected vacuum advance.

When I pulled the vacuum gage off the manifold vacuum port I expected the car to stumble and sputter for the second it took me to get the cap back on, but the engine picked up a little and idled smoother than when I put the cap back on? Is this normal? This is why I am still thinking the whole thing is running too rich.

 

[mchandford]

I still need to do the spark plugs, but I did get a timing gun. Pretty sweet deal I think. Pawn shop had a gun with the dial advance on it. You set the timing you want on the gun, then move the distributor until the TDC mark matches the pointer. Not a perfect way of doing it, but it seemed to work.

I figured out that the initial timing was set at about 20 degrees. This is the place that gives me the most vacuum, but it doesn't idle low enough for me, and it idles rough. I put it back to right at 10 degrees initial. Haven't had a chance to get it on the road to see if it is still rich, but it sounded better. Not sure how to check the total advance with the timing gun I have. I am thinking it would take two people. One to hold the throttle, and one to check the gun.

 

[marks73]

72Hcode had a fantastic post on getting everything in sync. I'll try to locate it but so far your doing a great job. Now comes the real tuning part. PITA from a time standpoint but well worth it.

This is not the one I was looking for but is close.

http://www.7173mustangs.com/thread-carburetor-hesitation?page=5

 

[mchandford]

72Hcode had a fantastic post on getting everything in sync. I'll try to locate it but so far your doing a great job. Now comes the real tuning part. PITA from a time standpoint but well worth it.

This is not the one I was looking for but is close.

http://www.7173mustangs.com/thread-carburetor-hesitation?page=5

He basically summed up what I have done so far. Vacuum tuned to the highest vacuum, reset idle, change air screws...all just to get an erratic idle and this very rich condition. Now I am going back to near stock initial timing: 10 degrees, and idle screws at 1.5 turns. Seems to be idling better and sounding smoother.