Ford 302 spark plug read

[Jakem]

Here is a few pics of plugs after switching to 4 barrel carb and intake. To me they look ok...any suggestions

 

[Scott Danforth]

Could go a tad richer on the jets

 

[Jakem]

I'm going to.order the calibration kit for this edelbrock 1409

 

[Jakem]

Now do I change primary jets or secondary...or both

 

[Scott06]

Wallace Racing - Spark Plug Reading

Look at the link your plugs show a tad rich on their scale. I had similar plugs on Mine thought they were lean bc insulator was clean, put an afr meter on and was way rich …

Plug reading is only good if you run it cut it off and read the plug immediately

 

[Jakem]

Is an afr meter worth me buying or shall I save my money for my next issue lol

 

[jimmbo]

Now do I change primary jets or secondary...or both

Well both the Primary and Secondary sides should be delivering the same Mixture Ratio to each cylinder, whether equal sized Jets will do that is a tossup. Are the Primaries and Secondaries the same Diameter, same Venturi size, and have identical Discharge Nozzles? Your Carb also uses Metering Rods, that throws another Curve into the equation. And the intake will affect what the ratio gets to each cylinder

Looking at the Insulator, I would say the engine is running lean, or the Plugs are too hot

An AFR meter, depending on where the sensor is placed could give the AF of One Cylinder, or the 4 on one side.

 

[Jakem]

I think I've beat the spark plug heat range to death on other postsand the outcome was to stick with the ones that came with engine..autolight 124...I've ordered a calibration kit and will fumble my way through the process and see what happens...goal being to fatten it up

 

[Scott06]

Is an afr meter worth me buying or shall I save my money for my next issue lol

I found it helpful as I had a lean spot after hitting the throttle due to slop in accelerator pump circuit then I was too fat on the step up rods.

I assume you have log not center riser exhaust manifolds? Not sure if these 02 adapters will fit your manifold and elbow configuration. https://www.hardin-marine.com/p-104396-o2-spacer-stock-mercury-riser.aspx

I think your plugs are fine where they are at. I also got similar comments on the dry porcelain being too lean... so I fattened things up. Still had a stumble, added the AFR meter and found I was way rich at cruise and wot, just had an initial lean spot from accel pump....

Corrected the slop in the accelerator pump linkage and basically went back to factory jetting/step up rods on the edlebrock 1409. Found it basically was set up well out of the box. Did you go with a edlebrock or other carb? If eddy this manual is very helpful https://www.edelbrock.com/media/wysiwyg/documents/carb-owners-manual.pdf

 

[Jakem]

I went with the edelbrock and performer intake. I didn't change anything aside from choke adjustment so far. Wich hole on accelerator pump did you use. Mine was on the top hole from the box

 

[Scott06]

I went with the edelbrock and performer intake. I didn't change anything aside from choke adjustment so far. Wich hole on accelerator pump did you use. Mine was on the top hole from the box

I used the top hole which is the biggest shot. I also replaced the accelerator pump nozzle with a larger one (.043 i think). The issue I had was there was slop in the accelerator pump linkage. Had to slightly lengthen the rod by straightening it out. This way the accelerator pump is under slight pressure so as soon as the throttle opens it is depressing the pump. That was causing me a long lean spot after nailing the throttle.

 

[Jakem]

Right o I'll give it a check thanks

 

[jimmbo]

I went with the edelbrock and performer intake.

Intake is Okay, but I can't respond Positively regarding the Carter Carb

 

[Bondo]

I think I've beat the spark plug heat range to death on other postsand the outcome was to stick with the ones that came with engine..autolight 124...I've ordered a calibration kit and will fumble my way through the process and see what happens...goal being to fatten it up

Ayuh,..... Go to the Edlebrock website, there's link there to the Bible of AFB carbs there,.....
It tells ya all the tricks, settings, etc,.....

For spark plug color tests, you need to run the motor at a given rpm, 'n then chop the throttle, 'n shut it down, then check the plug colors,.....

If you go out, 'n run it,.... then idle back to the dock to check, yer seein' the colors for the last few minutes it ran, not what it was doin' out on the pond,...

 

[Jakem]

Ahhhhh...gotcha...I'll install a new set before I hit the water...and do the test before I change any metering rods and su h...I got the calibration kit today...seems pretty straight forward to me

 

[Bondo]

Ahhhhh...gotcha...I'll install a new set before I hit the water...and do the test before I change any metering rods and su h...I got the calibration kit today...seems pretty straight forward to me

Ayuh,..... The AFB Bible,...

 

[dubs283]

Bondos post #14 explains correctly what is known as a plug burn. Great test to jet a carb specifically for the engine/desired performance. I choose to simply cut the ignition at a specific rpm under load instead of racking the throttle quickly and shutting down. Does run a risk of reversion/dieseling but with a proper set ignition and new plugs (required for the test anyways) the chances are low.

A plug burn is performed at a minimum of two different rpm, one for primary only and another with secondaries open.

Most people who perform plug burns are setting up their fuel delivery to achieve a certain performance. Most often performed on engines that are supercharged or upgraded big blocks designed to achieve maximum torque/horsepower.

Iirc your setup is a (maybe?) bored over 302? Even you're experiencing lean knock, extremely rich conditions or severe performance issues a plug burn isn't the right test for you

FYI the pics posted #1 look fine to me

 

[Jakem]

I just read the Bible and the chart that came with my calibration kit 1488 is different. Here's a pic of what I got

 

[Scott06]

I just read the Bible and the chart that came with my calibration kit 1488 is different. Here's a pic of what I got

What difference are you seeing? the book will have more combos then the kit.

I believe the kit is just a portion of what rod and jet combos are available. I ended up buying individual rods as I went.

 

[Jakem]

Here is the two sheets