bronco engine cranks but wont turn over

[alindao1991]

76 bronco, 302 v8, holley truck avenger off road carb
bronco sits unused for extended periods of time
brand new battery

before last april, never had a problem..

then last april, engine cranked but wouldnt turn over unless i sprayed starter fluid in carb. fuel pump works because gas poured out of fuel line when i disconnected from carb and pressed down on pedal. also put some new gas in tank as well. gave up because of other commitments

tried again last week. engine cranked but wouldnt turn over this time even after spraying engine stater fluid in carb. so, i dont know what the problem could be.

any suggestions are welcome. not much to go on, but any ideas would help. thanks!

 

[ryan97]

When fuel line connected to carb does it spray fuel in the carb barrels?
Jets in carb may be plugged or float hung not allowing carb bowl to fill.

 

[DaveLev]

Fuel filter, Seafoam into tank, check rear/side fuel switch under the seat, disconnect fuel lines from fuel pump and test fuel pump with tester while you crank over engine, possibly take top off carb while carb still on truck, blow out fuel lines, could be filter on sender in tank(s), maybe gremlin ate through your coil wire, etc. Get yourself quality digital volt meter and start taking measurements. You will smell gas in carb if you crank engine and pump throttle to flood engine. If no smell, most likely fuel delivery problem (what else could it be). If you smell fuel, and ether or other starting fluids don't get the vehicle to ignite, then check ignition related components. Hope this helps.

 

[Crush]

Cranking and turning over are the same thing. When it hits is when its running. So if you can crank it and it is not hitting means nonspark or no fuel. I spent two days trying to figure out my no spark issue and i had the wrong rotor button in my distributor cap. Have the large duraspark cap which requires the long rotor. Had the short rotor in and it wasnletting just enough spark to make it hit every once in a while. Man it was nice when ingot the right one. Lol

 

[jckkys]

Thanks. I don't know how this terminology got legs, at least on this sight. Turning over doesn't even sound like it could mean the engine starts or fires up.
It sounds like your not getting fuel to the Holley. The Truck Avenger has clear sight plugs in the float bowls. Can you see fuel when the engine fails to start? You would if the fuel is getting to the carburetor. Sometimes a little shake of the front end will get the fuel to the sight plug if the float level is set a little low. If you don't see any fuel after a few seconds of cranking to refill the bowl, where it dries out in about week, the fuel line or fuel pump aren't delivering it to the carb's float bowls. I don't think I ever found a use for ether (starting fluid) outside of cold weather diesel starting. Gasoline poured down the venturis would work as well as ether.
Pressing the throttle only pumps fuel, if there is any, out of the float bowl, and down the venturi. This is the function of the accelerator pump. The fuel pump should push fuel through the fuel filter and into the float bowl, when the engine is turned over/cranked.

 

[alindao1991]

fuel is definitely being delivered to the float bowls. i took both bowls (front and back) off. they were clean and not gunked up. a bunch of fuel came out of the front bowl when i took it off so gas is being delivered to the carb. so there must be some other type of blockage or delivery failure between the bowl and front barrels. i dont think fuel is being squirted into the barrels from the bowl. after i cranked the engin a few times again, i manually moved linkages to see if any fuel was being delivered into barrels. i couldnt see any...

 

[Crush]

Will it start on starter fluid or a small amount ofngas being put directly in the carb. If it does hit and run even for a second then u have a fuel problem. If itndoes not then unhave a spark problem

 

[jckkys]

Holleys were always difficult to keep running well, if they're allowed to dry out repeatedly. The gaskets are paper and both crack and warp. This problem is aggravated by the fact that both the float bowl and metering body gaskets are below the fuel level. Your description of fuel in the front bowl omitted whether or not the secondary bowl contained any fuel. Another question is, does the accelerator pump deliver fuel out of the nozzles when the throttle is opened? Just look at the booster venturis while you move the throttle lever. Any movement needs to produce streams of fuel directed at the booster venturis. A working carburetor also has obvious fuel spraying down the throttle bore from the inside of the booster venturis, when the throttle is opened on a running engine. If you spray carb cleaner directly into the jets. It should mostly come out of the booster.

 

[brianlowry]

Curious if you ever got it to start? I'm dealing with the same issue.

Put new battery in last night and it's cranking but not firing, but barely getting any fuel into the clear filter right before the carb. It was late when I tried it so I need to get back home to look at if there's spark and I just need to get the pump primed that I saw in another thread.

I switched back to a stock manifold so in terms of changing things to isolate the problem, I've changed a bunch..


Hope you figured out your issue!