My carb needs some help
Thread Starter
|
Posting Guru
Joined: Mar 2007
Posts: 1,119
Likes: 0
My carb needs some help
On my 84 F250 351w 2bl carb, if you are driving at low rpms, then punch the throttle, it bogs down and starts popping through the carb. If you let up on the gas, it stops and accelerates fine. Ive rebuilt the carb and it runs fine otherwise.
Moderator
Joined: Jan 2001
Posts: 56,997
Likes: 2,744
From: Virginia
Take the aircleaner off, and with the engine off, look down the carb throat, and just barely push the throttle back. Did you get anything out of the squirters for the accel pump? You can try again, and while watching the squirters, and making a mental note of how you are pushing on the throttle, push it back all the way. The streams of gas should start right away, and be very strong, especially since you just rebuilt it.
You can't have any delay in the fuel squirting down the carb throat, or you will get a bog and the popping. The popping is the engine leaning out. Don't experiment too much with out starting the engine, or you will flood it.
If that all looks good, then the timing could be way off, and it can have this symptom, but if it did not do it before, and after the carb was rebuilt it does it, then I would suspect you may have lost the check ball out of the pump circuit, and forgot to put it back in.
You can't have any delay in the fuel squirting down the carb throat, or you will get a bog and the popping. The popping is the engine leaning out. Don't experiment too much with out starting the engine, or you will flood it.
If that all looks good, then the timing could be way off, and it can have this symptom, but if it did not do it before, and after the carb was rebuilt it does it, then I would suspect you may have lost the check ball out of the pump circuit, and forgot to put it back in.
Thread Starter
|
Posting Guru
Joined: Mar 2007
Posts: 1,119
Likes: 0
Do you have a diagram of the springs inside the accelerator pump? Mine uses the diaphragm with the spring permanently attached if that helps at all, because Im not seeing any fuel squirting in, and the diaphragm is new.
Moderator
Joined: Jan 2001
Posts: 56,997
Likes: 2,744
From: Virginia
Here's a exploded view.
Carburetor Factory - American Motors 2100 Exploded View
More than likely you are missing #41, or #33 or #34.
Carburetor Factory - American Motors 2100 Exploded View
More than likely you are missing #41, or #33 or #34.
Thread Starter
|
Posting Guru
Joined: Mar 2007
Posts: 1,119
Likes: 0
I know 33 and 34 are there because I had to redo it after forgetting the check ball the first time. The rubber part (41) was replaced, but it doesnt seem to fit tight on the metal, it flaps around loosely. Is that normal?
Posting Guru
Joined: Jun 2004
Posts: 1,635
Likes: 0
From: Niceville, FL.
The elastomer valve shank should pass through the hole in the center of the pump chamber. You may have to apply a little grease to get it to pass through the hole and seat properly.
Trending Topics
Thread Starter
|
Posting Guru
Joined: Mar 2007
Posts: 1,119
Likes: 0
It did pull through past the bump, it just doesnt seal right. I think though that the metering rods not opening is also causing me problems.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Posting Guru
Joined: Jun 2004
Posts: 1,635
Likes: 0
From: Niceville, FL.
Sounds like you may have the wrong size elastomer valve. Do you still have the old one to compare? I think there may be two different (at least) sizes. The metering rods are actuated by a removable cam on the throttle shaft; is it still properly in place?
Posting Guru
Joined: Jun 2004
Posts: 1,635
Likes: 0
From: Niceville, FL.
I think your best bet is to get a rebuilt. Or, find a cheap used one and get the parts you need off it. I sent you a PM with a link to one on ebay that looks pretty close to what you've got.