I recently replaced my fuel tank and sending unit. Fired right up. Sat for a couple of weeks until I replaced my pitman arm and a brake line. Put everything back together and went to pull out of the garage and spit and sputtered. When I pump the pedal gas spurts in. Am I looking at a carburetor rebuild or is there something I am missing? Any help is greatly appreciated.
1977 f150 custom
351m

 

Crabdad,

I would check for spark, particularly since you have verified that you are getting fuel. If you have the original Duraspark ignition, that might be where you focus. If you search this forum for Duraspark you will get a ton of useful information. The ignition module itself can fail with little or no warning.

 

You might have stirred up some debris in the fuel lines and clogged the carb inlet valve Causing a high fuel level/flooding.

 

I know I need to change spark plugs for sure. It starts and sounds fine on high idle. When I kick it down it lopes and eventually dies. Ran great before I changed the tank.

 

Got it started. Let it run up to temperature. Messed with idle screw to keep it going. Looked inside carb. On side looks wet one side looks dry. That doesn’t seem right to me. I’m just a tinkerer. Learning a little everyday. Thanks in advance for all advice

 

My earlier post about checking for spark has clearly been disproven, given this additional information. Sounds like you could have a severe vacuum leak. You may want to review the recent repairs to see if you could have accidently done something to effect vacuum. For example, the vent line from the gas tank needs to be routed to the charcoal cannister up in the engine compartment on the left side, down low. If that line was left to "open air" instead of a vacuum you would get possibly get the condition you have now. You could also do a search on vacuum leaks to help eliminate this possibility.

 

I appreciate everything. I have not done a spark check yet. Feeling under the weather and just did what was easiest at this point. As for charcoal canister. I have two lines (filler and vent) hooked them up the way they were. Sending unit connection and hose which is new. Hopefully I’ll feel better next weekend to check for spark and vacuum leaks. Will I need anything specific to run those checks? You guys are great to have in my back pocket! Thanks in advance,

 

I hate it when there’s something bugging you that you need to do, and you don’t feel like it. Been there plenty of times. Of course, then there’s the weather…
If it ain’t one thing, could be another.

 

Going back to what you said about one side of the carb being dry, that could be a plugged jet in the bottom of the carb bowl. Might be worth your time to get a rebuild kit for the carb. It's pretty easy to take the lid off the carburetor and look for debris or sediment in the bottom of the bowl. If there's sediment in the bowl, it and all the passages in the carb need to be cleaned.

 

Read Beartracks and Drivewayfabricator post.
If you repair or service something and there is a sudden change in performance, always look back at what you repaired first before looking elsewhere.
Old rubber fuel lines deteriorate on the inside and if you move them around, sometimes this breaks a piece loose and it goes to the fuel filter or carb.
Replace any fuel filter.
Inspect all rubber fuel lines.
Make sure your carb is clean and free of trash. Especially at the needle valve.
If all is clean, then look at other possible causes.

 

I will do that. That makes sense now that I am feeling a little better. Brain was pretty foggy last weekend. Thanks to all.

 

Rained out today and decided to crawl underneath. Small section of connector hose should be replaced. Fuel filter, plugs and hose on the books for this weekend. If that doesn’t solve it .? I have a carb rebuild kit and a buddy who has a parts cleaning machine. A little nervous about rebuilding the carb though. Thanks to all

 

you can get them apart enough to clean them out without actually adjusting anything most of the time. i wouldn't bother with the parts cleaner and just get some carb or brake cleaner and focus on getting it to spray through the circuits. it will dissolved what would be most likely clogging it up.

most carbs only have 2 actual adjustments any ways. one being the idle and the other being the idle mix screw (air or fuel metering depending on where it is) the rest of the adjustments you have to actually change the item to adjust it. the idle is easy and simple to adjust and the idle mix screws are easy if you have a vacuum gauge (<$15).

don't sweat this.

 

Bought a vacuum gauge just not confident in using. Concrete guy for 30 years. While pondering situation with a beer or two. It took me a couple of tries to get the gasket on the sending unit to stay put. What if it wasn’t seated in correctly? Could the seal on the sending unit cause these symptoms? Spraying carb cleaner now. All the advice is greatly appreciated.

 

the vacuum gauge is easy to use... there should be a vacuum on the base of most carbs that will give manifold vacuum. plug it in there after its running and warmed up (your idle rpm and timing needs to be where you want it first too) and the needle should be steady pointing somewhere (likely between 16-20 but the literal number isn't super important... under 16 might mean you have a vacuum leak or an aggressive cam) if it's bouncing around, you have a vacuum leak somewhere you need to find and address first. if it's steady slowly (like 1-5 degrees at a time) start turning one of the idle mixture screws and see if it increases vacuum if it does, do it again and keep doing it until it stops increasing. if it doesn't turn it the other direction and follow the same steps in that direction. you want to target max vacuum; however, it will likely cause your rpms to rise so you'll have to stop and adjust that to your target idle rpm. once you aren't getting any higher vacuum, move to the next idle mixture screw, most carbs have 2 or 4 idle mixture screws.

don't be scared to mess up... if you do, just set it to what ever the carb manufacturer's starting setting is (with holley's i think it's 1.5 turns out) and start over.

the gasket with the sending unit wouldn't cause any issues unless it some how fell in the tank and blocked the pick up tube which seems incredibly unlikely.