I'm at a loss and need help. I have a 79 F100, 351m, 2wd, that has a edelbrock jr intake with a holley 650 sitting on top. After my new gas tank install I got it running. It idled for about 15 minutes, no leaks or anything of the sort. The next day after work I started it up comma it ran for about 10 seconds and then died. Here's what I've determined so far, I'm getting gas from the fuel pump pass the filter, into the bowl comma but nothing through the squirters when I push the throttle. I've adjusted the float level and it is perfect. I took the bowl off and cleaned it, I took the metering block off and cleaned it. I even got carburetor cleaner to go through the metering block and through the squirters. Still no gas even when the bowl is full and I open the throttle. And it still will not start. Any help is greatly appreciated but it's already dark here and I won't get to do anything until tomorrow. I just want to have a game plan for when I get off of work tomorrow. Thank you.

 

Nothing through the squirters points to an internal accelerator pump issue. Starting would be about impossible. Keep the battery on a charger so it can recover.

Holley has all their manuals and parts diagrams available for download, I'd want to find out why the pump ain't working. Maybe a check valve or something is bad. The fuel tends to do a number on the rubber parts these days. Holley light blue stuff is supposed to be ethanol tolerant. Has the carb been gone through lately?

 

Thanks Ted. I'm having issues viewing your comment, but I found a backwards way to see it. I'll the the accelerator diaphragm off first thing after work. Do you think three would be any visable tears or cracks? If the diagram looks good what should I check next?

 

I forgot, I rebuilt the carb about a year ago. By "rebuilt" I mean replaced all the gaskets and used carb cleaner and a tooth brush to clean it.

 

You could probably test it before re-installing it on the engine. Just be interesting to see what's what. Yes, the diaphragm could be torn or check valve damaged. Different carbs have different setups. Holley's have the red rubber check valve and pump diaphragm itself, the squirters, maybe a ball check. Did it work before?

 

yes it worked before, about two weeks ago(i was on vacation) it idled for about 20 minutes, let it sit while I cleaned up my tools and then started right up again. Greatest feeling in the world, until the next day it wouldn't start.


Today I removed the bowl and took off the accelerator pump diaphragm. It looked fine, no tears or holes that I could see. It moved just fine, so it's not hardened. Still no gas coming out the squirters(not sure if that's the right term). I've tried check holly's website, but it just suggests a complete rebuild. I don't know what to do at this point.

 

Turns out it was a stuck accelerator pump needle. Took that bad boy out, cleaned it and the passage. Thing fired up on second turn over. HOORAY! Now for the rest of the story. The next day (today) it won't start. First thing I noticed was fuel coming out the vent tube ... sigh. Opened the sight screw and fuel came spewing out. Tapped the fuel bowl with my plastic handled screwdriver, seemed to fix the flooding issue and the fuel bowl level. Now, it still won't start. Anybody got a grenade I can drop down the carb?

 

If it ain't another thing it's one thing. Keep pluggin' away, you will be rewarded with a reliable steed. Keep reading the manuals and troubleshooting guides, there's a LOT of good stuff online. Any carburetor has to be dialed in to the particular engine it's installed on. Most people don't seem to bother with the fine or even the coarse adjustments and usually have trouble.

 

Check to make sure your gas tank is properly vented. Could be the cause of pressure building up in your carb.
If you take the gas cap off and hear a sucking noise you might be vapor locking your carb.

 

What's killing me is I already rebuilt the carb last December. Since than, I've been starting it up and letting it idle for 10 minutes 2 or 3 times a month. Last night I figured it out. My stupid self got the float adjustment backwards. Thought I was raising it, when actually I bottomed it out. Started it up and sounded stronger than I ever remember it sounding. We'll see if it starts when I get home or if this is part of the pattern ... 😐😑😐😒

 

Today's gas cleans everything and not in a good way.
You may have a fuel filter before the carb but anything from there on is non filtered.
So the carb is cleaning it's self and will take time and longer if only running for 10 min. at a time.
I say drive the thing to get the gas moving in the carb.
Dave - - - -

 

Sounds like float/needle issue. Pull a plug and look. If wet, your flooded, gas coming from somewhere, if dry you are not flooded keep looking. No start when cold? No start when hot? No start at all? Might pay to check the ignition system. I have had champion plugs do this with the duraspark if too cool of a heat range. No start if below about 40*, Might notbe a carb issue. If plugs are dry, and spark when cranked, dribble gasoline into intake. see what happens, if it starts and dies then it needs gasoline, if it fires and sputters and pops might need more air and more gasoline, if pops and fire comes from somewhere, then it needs timed. This is a longshot, but might be worth checking, if thing starts when cold, idles but wont run or rev, then eventually dies, I am thinking 2 possibilities, lifters not staying pumped up and after a few minutes and some heat lifters finally collapse enough to not run. Seen this happen on 351m/400 in a bronco. After cooled off, she cranks up again until lifters collapse. Next is vapor lock. These are notorious for vapor lock. Especially if you have the "winter blend" fuel in still. Our stations locally didn't have the winter fuel all out until about a month ago, My truck wouldn't even run without electric fuel pump, then one day I filled up and no more electric fuel pump, no more winter fuel. Good luck.