What jet size is suitable for the 1986 Ford F-150 with a 300 L6 NP435 and Motorcraft 2150 carburetor?
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Great, you’ve got a 1986 Ford F-150 with the 300 inline-six and an NP435 manual transmission. That’s a solid setup. How can I assist you with it today? Are you looking for maintenance tips, troubleshooting advice, or maybe an upgrade suggestion? Let me know!
What is the correct jet size for my 1986 Ford F-150?
Ah, jetting the carburetor—always a fun task! The Motorcraft 2150 carburetor on your 300 L6 is pretty straightforward, but jet size can vary depending on a few factors like altitude and modifications you might have done to the engine.
Stock Jet Size
For a stock setup at sea level, the 2150 typically uses jets in the range of 47 to 52. That should give you a baseline to work from.
Modifications and Altitude
- Higher Altitude: If you’re at a higher altitude, you might need to go a couple of sizes smaller.
- Engine Mods: If you’ve modified the engine for higher performance—like a hotter cam or aftermarket exhaust—you might need larger jets.
Testing and Tuning
- Start Small: If you’re unsure, start with a slightly smaller size and work your way up. This way, you can avoid running too rich initially.
- Check the Plugs: After some driving, check your spark plugs. A good burn should be a light tan color. If they’re sooty, you’re running rich. If they’re white, you’re running lean.
Pro Tip
Always make one change at a time and test thoroughly before moving to the next adjustment. This way, you’ll know what’s working and what needs tweaking.
If there’s a Bullnose Garage video that dives into carb tweaking, it’s worth a look for some visuals and more tips. Otherwise, you might also find useful tips on the Bullnose Ford subreddit. Let me know if you need anything else!
What are the thread sizes for the jets in a 1986 Ford F-150?
The threads for the jets in a Motorcraft 2150 carburetor are typically 1/4"-32. This is a somewhat uncommon size, so when you’re looking for replacement jets or a jet kit, make sure they specify compatibility with the Motorcraft 2150.
Tips for Changing Jets
- Use the Right Tools: Make sure to use a screwdriver that fits snugly into the jet slot to avoid damaging them.
- Be Gentle: When installing new jets, thread them in gently to avoid cross-threading.
If you’re planning to play around with different sizes for tuning, it might be worth investing in a jet assortment kit specifically for the Motorcraft 2150. That way, you’ll have a range of sizes on hand to dial in the perfect mix for your specific needs.
If you have any more questions or need further clarification, feel free to ask!
This answer was written by Bullnose Bill, our AI shophand trained on hundreds of Bullnose-era Ford topics. He knows his way around old Ford Trucks.
As with all of Bill’s answers, it has been reviewed and approved by Ed Zenisek, the man behind Bullnose Garage and a real human being.
While we do our best to keep things accurate, always double-check any repair advice and use proper safety procedures. For real-world walkthroughs and more hands-on content, check out Bullnose Garage on YouTube or visit the BullnoseFord SubReddit.
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