Jets

[grandpaslincoln]

I want to re-jet my carb, I have an extra set, they are #50's. The ones that are in the carb right now are #49's. Here's my question(s) are 50's bigger, or smaller than 49's? I wanna tweak this thing a little to see if it will use less gas or not, because GL guzzles like crazy.

[turbo2256b]

50s are bigger. I bought a bunch of them at one time for motorcrat carbs. Have to look aat the sizes.

[Grand Marquis GT]

I used to have some...got em from parker carburetion...

[turbo2256b]

All mine are around 70 + or - around 5 sizes

[Tiggie]

Going from 49's to 50's isn't going to make much of a difference I wouldn't think.

The 49's are pretty small and you'll get maybe a tiny fraction better MPG with the 49's over 50's.

[grandpaslincoln]

So how small can I got without causing the carb to run lean?

[88MercWagon]

Didn't the car already have fuel starvation problems?

[grandpaslincoln]

It sucks gas like crazy, I don't think it's starving for anything, if anything it's a greedy bastard lol

[88MercWagon]

What about that issue you had with it starting to cut out/sputter around 4000 rpm?

[grandpaslincoln]

That could be a fuel pump issue

[gadget73]

Running lean doesn't always mean good gas mileage tho. The motor is making less power, so you have to put your foot into the pedal more to make up for it. Its also bad on the internals running lean like that. It can make the cylinder temps run high and melt the pistons in extreme cases. Running too rich is bad too, since it wastes fuel and washes down the cylinder walls with the excess fuel, causing increased wear from lack of lube. I'd check out that fuel pump thing and get that sorted out, then maybe play with jetting. The plugs will tell you a lot about how the engine is running, and an air/fuel mix guage is a great thing to have for stuff like this.