**Update** Got everything reassembled. I ended up having to make a gasket for the intake to spacer. Everything the parts stores stocked have cutouts in places I didn't need them. I found one that was very close, listed for a 1980 302/2bbl intake but noticed a sliver of mismatch. I'm confident that's the gasket the PO used when it was converted to carb...and the source of the vac leak.

Runs smoother now, no more hesitation/stalling...just need to fine tune timing and carb.

Bad news...since my "spring cleaning" I now have a pretty bad leak from the driver side valve cover. At least that should be an easy fix for once.

Thanks to all of you for your help with this!

 

Glad you got it fixed. A valve cover leak is pretty easy, I'm sure you know, so you are closing in on peeling this layer of the onion.

 

Thanks Gary...I think I peeled too deep though. I picked up a new fan shroud while I was at the JY and figured I'd humor myself to see if I could wrangle it in without having to remove the radiator. So...now I have a hole in my radiator. Turns out those little water passages are pretty fragile.

One step forward...two steps back.

 

Bummer! Oh well, a new shroud and radiator will be good.

 

**New Issue** I posted this in the 'small block' forum but didn't get many bites, so I'll ask here...

I checked my timing, due to still feeling sluggish after fixing the vacuum leak/hesitation issue. Found TDC and verified that it matched the 0* mark on the balancer. Checked the timing and I could not find the mark unless I dialed the timing advance to ~30-32*. This was with the engine warmed up and the vac advance disconnected and plugged. I tried to back it down but the engine wanted to stall. I assume that ~10* BTDC would be normal but the engine will barely run at that timing...it pings badly and barely idles. I hooked up a vacuum gauge and found that I have max vacuum (~22cm) with the timing reading in the 30-32* range on my timing light.

It seems as if the engine runs smooth with the vac advance disconnected but when I reconnect it I develop a slight miss. I have reconnected and disconnected the vac advance several times to verify that the miss only exists when the vacuum advance is connected. All of this is noticed at engine idle.

Is there a particular reason why...

1. My timing seems to be way high
2. I develop a miss with the distributor vac advance connected at idle?

***disclaimer*** I bought my timing light at harbor freight. It has a dial for degrees of advance, but I'm not convinced that it is accurate. I've tried using the advance settings with a mark for TDC and by marking the 10* on the balancer and leaving the timing light at 0*. Either way it shows my timing in the 30-32* range.

 

If the engine won't idle well at ~10 BTDC but runs well at 32 BTDC then you have a timing light problem or a harmonic balancer problem. My guess is it is the timing light since it is apparently new, and since you say you checked TDC.

So, how did you check TDC? If you are sure you did it correctly I'd borrow another timing light.

 

I used a piston stop and rotated the engine both directions, marking the stop points. Dead center of those two points was the 0* mark on the balancer. I also did the finger over the #1 plug hole while rotating to verify compression stroke and that the marks ended up the same for TDC.

I'll see if I can find another light to borrow...

 

Looks like you did an excellent job finding TDC. Must be the light. Please let us know.

 

**Reviving an old thread**

I'm still fighting issues with poor acceleration. Timing has been set, verified and verified again. Idles fine and runs ok at speed, just will not accelerate without dying or falling on its face. I replaced the fuel pump, filter and installed another filter near the carb (clear inline type) just to get a visual on the fuel flow. All of that looks good.

I can make it accelerate but it takes a LOT of feathering of the pedal to baby it along until it gets up to speed. I'm thinking maybe the power valve?

This is a rebuilt Motorcraft 2150 2bbl (Uremco 7-7551), for reference.

I would love to get a 4bbl intake and carb, drop it in and never look back and I'm leaning that way since this problem appears to be all fuel/carb related. Is there anything else that would possibly cause these symptoms?

 

You have a lean condition that can be caused by several things:

1. Have you verified that you have two streams of gas shooting into the carb when you hit the throttle - engine off? It is very possible to have the accelerator pump discharge nozzles plugged or have forgotten the check valve - either of which will cause the problem you are seeing.
2. Or, as you suggested, maybe it is the power valve itself or the passages leading from it into the intake. What valve do you have in? And, does the engine run better at full throttle?
3. How about a major vacuum leak? Have you checked with carb or brake cleaner squirted around the base of the carb when running? If you have a leak, it'll suck the cleaner in and burn it, which will speed up the engine for a second or two.

 

I definitely have two strong streams when pumping the throttle.

Not sure what valve I have...I didn't realize there were variations. Engine runs fine at any throttle range when in park. The problem only arises when in drive and accelerating from a stop or low speed. It is a little "surgey" at highway speed but accelerates a little better from cruising speed. Mostly dies on takeoff, where feathering the throttle is necessary to get it up to speed.

I initially had a vac leak at the carb spacer, which was fixed. I can't find evidence of any vac leaks now...vacuum pressure holds steady at 20hg.

 

Ok, scratch the accelerator pump idea as it is working.

As for the power valve, my page here shows what is available: 2150 Power Valves - ???Gary's Garagemahal. And, as you can see, they range from opening at ~2.5" to 11.5". That's a huge range. And, if you are jetted lean and have a 2.5" valve in you'll have a hard time accelerating unless you floor the throttle.

So, that leads me back to the question: How does it accelerate if you floor it after getting up to 30 MPH or so? If it runs well then but has no power until you get the throttle fully open then you may well have the wrong power valve in.

Assuming it runs well floored, you need to hook up a vacuum gauge and run it into the cab. Drive it and watch the gauge - you'll see at what vacuum the power valve opens, which is when the engine responds properly. Now drive and watch the gauge and try to determine at what point in the vacuum range you want the valve to open to give you the surge of power.

 

It appears that...

At idle, I'm at around 24" vacuum. Upon accelerating, it dies when the vacuum drops to 10 or below under normal throttle accel. Cruising along 35-45mph the vac is around 15". If I floor it at ~35mph it responds properly (for a 302 w/2bbl :/).

I'm guessing I need to pull the carb and verify which pump I have...or...

since I'm wanting a 4bbl anyway, would I be better off getting an Edelbrock Performer intake and Holley 600cfm carb and be done with it?

 

Your call. But a 4bbl only helps at high RPM, not low. So, if you don't wind it up you won't get any benefit.

But, it seems like you are jetted quite lean. If you had a power valve that opened at 10 - 11" it would cover up the bog you are getting. However, that's an unusual power valve as most are down around 6 - 8". So, the issue is that your carb is jetted very lean. You could easily rejet and probably pick up some throttle response. And, rejetting a 2150 is easy as you just pull the top off the carb w/o removing it from the engine. That's what I would do instead of changing the PV to cover up lean jetting.

 

Understood w/ the 4bbl idea. Not sure the $600 is going to be much bang for the buck.

That said, How can I verify exactly what I am currently dealing with? Are the jets stamped with a size/number? How about the power valve? What determines the color coding? I assume its something internal as I have no markings on the outside/cover of it...