Fixing Eddie

[Gary Lewis]

Hi.

Took Eddie out this morning for a test drive. AFR readings are hovering around 13,3 at all speeds from 20 - 65 mph.

At idle 13,3

Engine 100% warmed up.

When accelerating normally afr starts at 11,4.

So the saga goes on🙂

Greetings Stein

It is good that the AFR is consistent across all those speeds. I still think you need to lean it out some if you want better economy. But if it is running well then maybe you are happy?

However, I think your idle AFR is a bit lean. In my experience things have worked better with an idle mix closer to 12:1. But again, if your engine is happy then maybe you don't want to change it.

[firefire]

It is good that the AFR is consistent across all those speeds. I still think you need to lean it out some if you want better economy. But if it is running well then maybe you are happy?

However, I think your idle AFR is a bit lean. In my experience things have worked better with an idle mix closer to 12:1. But again, if your engine is happy then maybe you don't want to change it.

Hi.

Engine is running well and also at idle. The idle does not even react with lower rpm when I put the transmission in D. I checked vacuum today at idle. It is 15-16 hg. Ignition 12 btdc. Opening the idle screws did not give higher vacuum value. Actually I adjusted them a little leaner. Maybe 1/8 of a turn.

I decided to change the primary jets to one size smaller. So I got the carburetor off the engine and on the work bench. Following Holleys instruction I found this :

Choke function OK

High Idle Off adjustment OK

One of the 2 phillips head screws on top of the carburetor was loose.

The 6 Phillips head screws at the underside were all tight.

Checked the Floats. Shall be 1.01" They were 1,14" and 1,05"

Using a small wrench I could hold the arm and push/ pull the float to bend the arm. Adjusted them as close as I could to spec.

Choke blade axel loose in joint with outside arm. In photos you can see the amount of play when choke is open. Probably it doesnt matter. The choke closes 100%.

Disconnecting accelerator pump rod OK

Was not possible to disconnect choke linkage after removing the E-ring retainer. Had to unscrew nut and remove little arm.

Seperating carburetor air horn from fuel bowl OK .

The Primary and Secondary jets were size 0.08". Stamped 80.

Changed the Primary jets to 0.076". That is a reduction of the area by 10%.

Put in metering rods size 0.062 x 0.054. At the thick step thats a reduction of the area by 6%.Compared to the metering rods I had in the 0.080 jets.

This is just some mathematics trying to figure out what I have done. Had to reuse the blue gasket. At one spot the fuel bowl had split the gasket longitudial. Test drive tomorrow.

What can I say about the Street Demon ? It is very easy and straightforward to work on.

 

[Gary Lewis]

Hi.

Engine is running well and also at idle. The idle does not even react with lower rpm when I put the transmission in D. I checked vacuum today at idle. It is 15-16 hg. Ignition 12 btdc. Opening the idle screws did not give higher vacuum value. Actually I adjusted them a little leaner. Maybe 1/8 of a turn.

I decided to change the primary jets to one size smaller. So I got the carburetor off the engine and on the work bench. Following Holleys instruction I found this :

Choke function OK

High Idle Off adjustment OK

One of the 2 phillips head screws on top of the carburetor was loose.

The 6 Phillips head screws at the underside were all tight.

Checked the Floats. Shall be 1.01" They were 1,14" and 1,05"

Using a small wrench I could hold the arm and push/ pull the float to bend the arm. Adjusted them as close as I could to spec.

Choke blade axel loose in joint with outside arm. In photos you can see the amount of play when choke is open. Probably it doesnt matter. The choke closes 100%.

Disconnecting accelerator pump rod OK

Was not possible to disconnect choke linkage after removing the E-ring retainer. Had to unscrew nut and remove little arm.

Seperating carburetor air horn from fuel bowl OK .

The Primary and Secondary jets were size 0.08". Stamped 80.

Changed the Primary jets to 0.076". That is a reduction of the area by 10%.

Put in metering rods size 0.062 x 0.054. At the thick step thats a reduction of the area by 6%.Compared to the metering rods I had in the 0.080 jets.

This is just some mathematics trying to figure out what I have done. Had to reuse the blue gasket. At one spot the fuel bowl had split the gasket longitudial. Test drive tomorrow.

What can I say about the Street Demon ? It is very easy and straightforward to work on.

I think you'll see a lot leaner mix in the morning. Both from the smaller jets as well as the lower float level.

As for the idle mix, turning the screws in was the right direction. You were already rich so needed to have less fuel, and the screws restrict the fuel when turned in. And that should raise the vacuum at idle.

I think with a stock cam you should be seeing at least 18" if not 20". But you might want to dial in another 2 degrees of advance once you get the AFR set where you want it and see if that doesn't bring the idle up and give the engine a bit more spunk.

But everything is looking good! The carb looks nice and clean.

[firefire]

I think you'll see a lot leaner mix in the morning. Both from the smaller jets as well as the lower float level.

As for the idle mix, turning the screws in was the right direction. You were already rich so needed to have less fuel, and the screws restrict the fuel when turned in. And that should raise the vacuum at idle.

I think with a stock cam you should be seeing at least 18" if not 20". But you might want to dial in another 2 degrees of advance once you get the AFR set where you want it and see if that doesn't bring the idle up and give the engine a bit more spunk.

But everything is looking good! The carb looks nice and clean.

Hi again. After a longer period with warm weather we are now back to refrigeretor temps at daytime .

Have done more testing with the Street Demon. The primary Jets are .076" Metering rod 6052. Metering Rod Spring Green 6HG. Several trips with this gave AFR 14,2 while cruising at all speeds. Put in a orange spring 5HG in a try to get a leaner mixture under part throttle. I did get surprised when I now got 13,5 AFR when cruising. Should not be affected by the spring. Engine temp hit the A in Normal at the end of the trip.

To hot for my liking. This had happened one more time earlier that week. When I got home I removed the air filter. There I saw the choke standing partially over the fuel shower heads The cause of this is explained in previous post. Could this cause the lower AFR and heat ? I pushed the choke blade to the straight down position and hit the road again. Now the AFR was back to 14,2 and the temp. stayed at the O in Normal. Partial throttle AFR 13,8.

So I decided to bend the choke arm more to make it shorter. That will hold the choke blade properly open. To fix this properly I will have to fasten that little arm securely to the choke axel. As an experiment to richen up partial throttle I put in the strongest spring, silver 8HG. This should cause the metering needle to rise more at partial throttle I thought. I think the metering rod will stand in any position in the jet depending on the actuall strenght of vacuum.

At cruise I got AFR 14,3. Partial throttle started at AFR 12,5. At WOT the AFR bottomed out at AFR 10.

Thats to rich. I will try smaller Secondary Jets later.

But since its so easy to change metering rods I decided to try the next leaner step. Rods 6254. This resulted in AFR 15,5 at cruising and many times I saw AFR 16-18:nabble_smiley_oh: I could also feel Eddie had lost power. Partial throttle AFR 13,3. At the end of the trip the temp reached M/A in Normal. So I changed back to the 6052 metering rod.

So now its out and under the hood to get the carburetor out and on the work bench.

During the testing Eddie fuel consumption has been 19 l/100km or 12,4 mpg.

Greetings Stein.

 

[grumpin]

Hi again. After a longer period with warm weather we are now back to refrigeretor temps at daytime .

Have done more testing with the Street Demon. The primary Jets are .076" Metering rod 6052. Metering Rod Spring Green 6HG. Several trips with this gave AFR 14,2 while cruising at all speeds. Put in a orange spring 5HG in a try to get a leaner mixture under part throttle. I did get surprised when I now got 13,5 AFR when cruising. Should not be affected by the spring. Engine temp hit the A in Normal at the end of the trip.

To hot for my liking. This had happened one more time earlier that week. When I got home I removed the air filter. There I saw the choke standing partially over the fuel shower heads The cause of this is explained in previous post. Could this cause the lower AFR and heat ? I pushed the choke blade to the straight down position and hit the road again. Now the AFR was back to 14,2 and the temp. stayed at the O in Normal. Partial throttle AFR 13,8.

So I decided to bend the choke arm more to make it shorter. That will hold the choke blade properly open. To fix this properly I will have to fasten that little arm securely to the choke axel. As an experiment to richen up partial throttle I put in the strongest spring, silver 8HG. This should cause the metering needle to rise more at partial throttle I thought. I think the metering rod will stand in any position in the jet depending on the actuall strenght of vacuum.

At cruise I got AFR 14,3. Partial throttle started at AFR 12,5. At WOT the AFR bottomed out at AFR 10.

Thats to rich. I will try smaller Secondary Jets later.

But since its so easy to change metering rods I decided to try the next leaner step. Rods 6254. This resulted in AFR 15,5 at cruising and many times I saw AFR 16-18:nabble_smiley_oh: I could also feel Eddie had lost power. Partial throttle AFR 13,3. At the end of the trip the temp reached M/A in Normal. So I changed back to the 6052 metering rod.

So now its out and under the hood to get the carburetor out and on the work bench.

During the testing Eddie fuel consumption has been 19 l/100km or 12,4 mpg.

Greetings Stein.

On the temperature, are you checking it with an infrared thermometer?

I don’t put much faith in the factory temperature gauges. When I first got my truck I checked it at the thermostat housing with an infrared thermometer. Eventually I put in an aftermarket gauge.

Like one of these,

https://www.thermoworks.com/ir-gun/?utm_source=google_shopping&utm_medium=organic&gclid=EAIaIQobChMIgLf9jaCy9wIVXRmtBh2Q4QrxEAQYAyABEgLS9fD_BwE

 

[StraightSix]

On the temperature, are you checking it with an infrared thermometer?

I don’t put much faith in the factory temperature gauges. When I first got my truck I checked it at the thermostat housing with an infrared thermometer. Eventually I put in an aftermarket gauge.

Like one of these,

https://www.thermoworks.com/ir-gun/?utm_source=google_shopping&utm_medium=organic&gclid=EAIaIQobChMIgLf9jaCy9wIVXRmtBh2Q4QrxEAQYAyABEgLS9fD_BwE

I would not make tuning adjustments based on AFR readings obtained with the engine below operating temperature. For reasons I dont fully understand, it seems to matter a good bit.

12.4 miles/gallon for a carbed 351W with a C6 would be considered pretty typical around here if I had to guess. I would think you might get as high as 14 with more tuning work and gentle driving.

Sounds like its all coming along nicely!

[Gary Lewis]

Hi again. After a longer period with warm weather we are now back to refrigeretor temps at daytime .

Have done more testing with the Street Demon. The primary Jets are .076" Metering rod 6052. Metering Rod Spring Green 6HG. Several trips with this gave AFR 14,2 while cruising at all speeds. Put in a orange spring 5HG in a try to get a leaner mixture under part throttle. I did get surprised when I now got 13,5 AFR when cruising. Should not be affected by the spring. Engine temp hit the A in Normal at the end of the trip.

To hot for my liking. This had happened one more time earlier that week. When I got home I removed the air filter. There I saw the choke standing partially over the fuel shower heads The cause of this is explained in previous post. Could this cause the lower AFR and heat ? I pushed the choke blade to the straight down position and hit the road again. Now the AFR was back to 14,2 and the temp. stayed at the O in Normal. Partial throttle AFR 13,8.

So I decided to bend the choke arm more to make it shorter. That will hold the choke blade properly open. To fix this properly I will have to fasten that little arm securely to the choke axel. As an experiment to richen up partial throttle I put in the strongest spring, silver 8HG. This should cause the metering needle to rise more at partial throttle I thought. I think the metering rod will stand in any position in the jet depending on the actuall strenght of vacuum.

At cruise I got AFR 14,3. Partial throttle started at AFR 12,5. At WOT the AFR bottomed out at AFR 10.

Thats to rich. I will try smaller Secondary Jets later.

But since its so easy to change metering rods I decided to try the next leaner step. Rods 6254. This resulted in AFR 15,5 at cruising and many times I saw AFR 16-18:nabble_smiley_oh: I could also feel Eddie had lost power. Partial throttle AFR 13,3. At the end of the trip the temp reached M/A in Normal. So I changed back to the 6052 metering rod.

So now its out and under the hood to get the carburetor out and on the work bench.

During the testing Eddie fuel consumption has been 19 l/100km or 12,4 mpg.

Greetings Stein.

I missed your post, Stein. Sorry.

But you are right that the 15.5 AFR when cruising is lean, and 16 - 18 is way lean. However, I doubt that at your cool outdoor temps the engine coolant temp could change with an AFR change. Yes, the leaner mix can cause cylinder temps to rise some, but if your cooling system is working properly I can't see that causing the temp to go up enough to see on the gauge.

And if the choke plate isn't standing straight up I'd think that would tend to cause the AFR to be a bit richer, not leaner. However, perhaps it changes the airflow in the carb enough to cause it to go lean?

Anyway, you are going about it the right way, a bit at a time. And I agree that 12.4 MPG isn't too bad with your engine and transmission if you are doing a lot of slow speed driving as well as some highway. But on the highway I'd think you could see something like 14.

[firefire]

I missed your post, Stein. Sorry.

But you are right that the 15.5 AFR when cruising is lean, and 16 - 18 is way lean. However, I doubt that at your cool outdoor temps the engine coolant temp could change with an AFR change. Yes, the leaner mix can cause cylinder temps to rise some, but if your cooling system is working properly I can't see that causing the temp to go up enough to see on the gauge.

And if the choke plate isn't standing straight up I'd think that would tend to cause the AFR to be a bit richer, not leaner. However, perhaps it changes the airflow in the carb enough to cause it to go lean?

Anyway, you are going about it the right way, a bit at a time. And I agree that 12.4 MPG isn't too bad with your engine and transmission if you are doing a lot of slow speed driving as well as some highway. But on the highway I'd think you could see something like 14.

Hi. It could be the gauge or temp. sender causing the variations in temperatur. And I suspect the choke disturbing the airflow caused the richer AFR.

And its still pretty cold here. Snow at 300 meters and higher 😱.

When it comes to fuel consumption check out Thunderhead289 on Youtube. V8 with lawn mover carburetor 😀. I think his videos are really good.

Greetings Stein

[Gary Lewis]

Hi. It could be the gauge or temp. sender causing the variations in temperatur. And I suspect the choke disturbing the airflow caused the richer AFR.

And its still pretty cold here. Snow at 300 meters and higher 😱.

When it comes to fuel consumption check out Thunderhead289 on Youtube. V8 with lawn mover carburetor 😀. I think his videos are really good.

Greetings Stein

Wow! That

is wild! A carb with a computer-controlled vacuum leak to put the AFR at the target. Interesting!

[firefire]

Wow! That

is wild! A carb with a computer-controlled vacuum leak to put the AFR at the target. Interesting!

Yes. It is beyond my capabilitys. I thought it must be interesting for some of the more expert members of this forum. I can only say I am impressed 😀.

Stein.