1977 Spider - New 32/36 issues

[lCarlCarlsonl]

Hello all, I'm hoping some of the expertise on these forums can help me out.
I've recently installed a new EMPI 32/66 from vicks and have had some issues running rich that I am struggling to solve.

Background:

-Installed all new vick exhaust and headers
-installed new empi 32/36
-installed new AFR gauge using the header outlet for the O2 sensor
-added an electric fuel pump with in-line regulator set at 3psi (no noticeable affect
Rest of the engine appears stock, or at least "Old". I bought the car from an owner who knew nothing about them and thought the car was FWD. 1800 size

Problem:
I installed the new carb and everything ran ok, but very rich and a high idle that wouldn't move. This was the stock 60/50 on the idle circuits (primary/seconday), and when trying to tune I was unable to get the idle to react to either of the screws mixture or rpm. O2 gauge red about 10 AFR, and 1200 RPM
I then swapped the idle circuits as I'd seen that on a few videos (50/60) and was able to get the car to idle a bit lower 1050 RPM, and O2 reading of 11 AFR.

Last update I went and put in a 45 for the primary idle jet and can now tune to a nice 13.5 AFR on my O2 gauge, but it feels like I've lost power. Starting the vehicle it now needs to warm up even in 60F weather, or stalls out. My AFR gauge will read a solid 13.5 based on my target, but then driving the car feels like it's down on power. As I accelerate I tend to go lean and then the car catches up (I'm not sure if that's normal). Finally, after driving 20 minutes I bring the car to park and my O2 is now reading 12.6 AFR.

This is my first time tuning a carb, and was hoping the O2 sensor would simplify things, but i'm finding it's just pushing my brain to aim for perfection.
Questions:
- Does a 45 primary on the 1800 make sense? I've not seen anyone use this size (though have seen it on a 1600)
- My plan was to go up on the air correctors and then see if that improves it? .. then size the idle jet appropriately.
-Would any internal changes on the carb cause this? Should i check and adjust the float?

Thanks for any help you can provide, luckily the car is drivable and I can still go out an enjoy it, i just feel i'm missing something simple to get it tuned right.

[Nut124]

I have a -78 with IDFs and a wideband O2. I tune for drivability and power, not for a target number.

At idle and low speed these like to run on the rich side. I'd be OK w 11-13 AFR at idle and low speed. A little rich always runs good, while lean does not. Idle AFR should be done with the idle mixture screw, not the jet. The idle jets are more important for the progression circuit, which is active under low speed and low load. If you lean these jets too much you will get lean gaps where the carb switches from the idle/progr circuit to the main circuit.

For best power at top end, WOT, I target 12.5 to 13.0.

The idle speed should adjust down using the idle speed screw which sets the butterfly stop. Does your accel cable allow the plates to fully close?

[lCarlCarlsonl]

Thank you for the response,
I don't mind running rich, but on the larger jets the engine was unresponsive to either the idle speed of mixture screw. It seemed to settle at an rpm of 1200-1050 (checked with timing light) and then the mixture screw had no effect. Hence going down to the 45 primary idle.
With the 45 jet, the engine reacts to the tuning screws

I do plan to pull the plugs this week and check their condition. I am concerned about fouling plugs if I'm idling at ~11 AFR, I expect a hard acceleration will drop below an ideal condition.

[lCarlCarlsonl]

I forgot to mention, throttle plates close fully (did most of my checking with the throttle cable disconnected to see if that was the issue at one point). I adjusted the 2 stage choke and it now starts and drop down appropriately.
After a bit more fiddling i'm concerned my sensor is on the way out so (was now running lean at idle and erroring out).

I managed to pull the plugs and they all look great, so that's a good sign.

[Nut124]

If you cannot stall the engine by turning down the idle speed screw, closing the plates, then it is likely you have a vacuum leak somewhere in the intake or carb base that supplies air to the engine around the carb.

Vac leaks totally mess up any AFR work at low speed, idle.

There are some OK videos on how to locate vacuum leaks.

[lCarlCarlsonl]

I have checked a few times and can find no vacuum leaks. With the smaller 45 jet I am able to get the idle screws to react on the engine.
I think i'll start playing around with the jetting and see if i can hit my target values.
It's entirely possible this engine isn't even an 1800 (I've only had the car a year and never actually checked it's not been replaced with a 1600)

[davidbruce]

Have you checked your float level? I had a new Empi 32/36 that was difficult to tune. I took the top off the carb and found that the level was too high. I also found what looked like sand in the float bowl. It was actually brass and pot metal filings from the manufacturing process. I have read that genuine Weber''s suffer from this problem as well. Fixing these 2 problems made the carb tunable but I tweaked it several times over the following days before I was happy. I wondered if the debris in the bowl had to work it''s way through the carb. I also did go down in size on the primary but don't remember if it was a 45. This was on a 2 litre in the 73 I no longer own.

[Nut124]

Turn the idle speed screw down all the way. The butterflies should be completely closed. Does the engine still idle?

If so, put your palm on the carb and block air flow. Does the engine still run?

[lCarlCarlsonl]

Have you checked your float level? I had a new Empi 32/36 that was difficult to tune. I took the top off the carb and found that the level was too high. I also found what looked like sand in the float bowl. It was actually brass and pot metal filings from the manufacturing process. I have read that genuine Weber''s suffer from this problem as well. Fixing these 2 problems made the carb tunable but I tweaked it several times over the following days before I was happy. I wondered if the debris in the bowl had to work it''s way through the carb. I also did go down in size on the primary but don't remember if it was a 45. This was on a 2 litre in the 73 I no longer own.

Thanks David,
I did take some time to check and reset the float, I also swapped in a new top gasket I had lying around just to confirm that wasn't a hidden vacuum leak.
Covering the intake stalls the engine and I'm confident there are no vacuum leaks at this stage.
I feel like installing a wideband just has me chasing "perfect" conditions, but it seems like many people spend a few weeks trying to dial in their carb setup so at least it's a normal process.

I do have a card spacer lying around I plan to drop in once it warms up a bit (as it decided to snow in Detroit today) and then I'll go back to playing with the tuning and new jets I have and report out if I get an improvements.