Black 84 Z

Here is the situation, 2 months or so ago I rebuilt my leaking Holley 650 dp carb. It ran fine until 2 weeks ago when the radiator puked most of the coolant out while crossing a bridge. I ended up replacing the radiator and a water pump to block gasket. After doing that I started it up to check for leaks and it idled just fine with no problems so I took it out on the road. After about 2 miles the engine started to stumble before dying completely, no signs of a problem under the hood so I tried a couple of times to crank it. It cranked but would not fire. After getting towed home i once again tried to crank it but this time no dice (battery is fully charged). I pulled the plugs one by one and gas came pouring out of a couple of them and the others were wet with gas. I drained the oil and there had to have been a couple gallons of gas/oil that poured out. Figuring that draining it pan would at least free up the engine I tried to bump it over with the starter (not crank it) but still nothing but clicking noises.

Couple of questions:
1. I've read that a stuck float or a fuel pump going bad can cause the gas in the pan. I did just rebuild the carb recently, but since it was running fine until suddenly dying I am leaning toward fuel pump, what do you guys think??
2. I'm concerned that it will not even turn over right now, should I refill the engine with oil and pull all of the plugs to see if it will at least crank with no cylinder pressure?? If so, then....
3. How do I go about "cleaning" the gas out of the crankcase? Should I just run it a few minute with the new oil then change it out real quick or is there something else I should use?

Sorry for all of the questions, I am just getting really frustrated as It has been one thing after the other lately. i just want my car back running!!! lol

ric28z

I had a similar problem with my 82 firebird shortly after the engine was rebuilt. Turned out the fuel pump was at fault and letting fuel into the sump.
Sounds like this may be your problem too,
As for the no crank over situation could be the fuel has diluted your oil down to a point where it has little or no lubrication qualitys and the starter cannot overcome the increased friction of metal on metal
Hope this helps

Black 84 Z

Thx for the info, I am going to pull all of the plugs and see if it will turn the engine with no compression. Hopefully it will so I know the internals are alright.

Another thing I thought of, if the fuel pump ruptured would gas be able to pour into the cylinders like it did?

ric28z

As for fuel in the cylinders, that kind of blows my theory, on rethink the fuel must be coming from the carb, flooding the cylinders and leaking down past the rings to the sump, would also leave the cylinder walls completely dry and make it very hard to turn over. Looks like you need to pull that carb back off and see whats up. I know the Q Jets can leak fuel into the manifold through bad castings or leaking plugs but dont know too much about Holleys...
Maybe someone else can jump in with more ideas.

Cheers

88PontiacT/A

I agree with ric28z except that I will say this; If liquid fuel came out of some spark plug holes whenever the plugs were removed, that is the reason the engine wouldn't turn over. Liquid will not compress in the combustion chamber the way air/fuel vapor does. The first thing I would check as far as the source of the problem is concerned is the carb.
Here's my theory: the carburetor was dumping way too much fuel into the intake due to a malfunction of some sort (stuck float, etc.) Once the engine flooded and died, the rest of the fuel that was in the carb drained out and filled a couple of the the combustion chambers and stopped the engine from turning over, while some of the fuel leaked past the rings and contaminated the crankcase oil. Also are you using a mechanical fuel pump or an electric one? I'm guessing mechanical?

John C.

Black 84 Z

Yeah, I have a mechanical pump. Probably going to have to pull the carb again and see if I can figure out WTH happened that could dump GALLONS of gas into the cylinders and oil pan. As a bonus, my battery mysteriously died for no apparent reason, after all of this it now can't hold a charge long enough to turn on the stereo let alone turn the engine over. Maybe it was already dying and that is why it wouldn't turn the engine over (yeah right).

91phoenix

iTrader: (5)

There is no way that a carb going bad can dump gallons of gas into cylinders etc. Even with a fuel pressure regulator gone bad you would not get that much and he said a mechanical fuel pump. The carb can only empty its bowl and then it is done except for slight residual pressure in the fuel line. Admittedly it was apparently running poorly for a little and it would refill the bowl but then it can not seep enough past the rings to fill the pan and keep running.
With the radiator problem I am wondering if some of that wasn't coolant. I know that it should make oil milky but have seen it just not mix if not ran.
I would suggest pulling the plugs and try turning it over. If ok then do a compression test. If that is still ok then I would look at rebuilding the carb. As for the gas in the crankcase do just as you said. Change the oil and run for a few minutes and then change. The gas that is left should just evaporate out of there after the oil is drained but I prefer to be sure and just change the oil after 5 minutes.

TreeFiddy

Blown power valve will dump raw fuel right down the manifold.

poloaa008

Good thread, I always like them.

Black 84 Z

Could a blown power valve dump that much fuel into the cylinders, literally gallons?? If so that is the most likely culprit I think as I can't come up with anything else. Can you tell by looking at it if it went bad??

Update, my battery was COMPLETELY dead (like overhead light won't come on dead) so I took it to get tested, came back fine just needed a good charge which they did for me. Hooked it back up and tried to bump it over and the engine budged just a bit. After that I pulled the plugs and tried again, this time it turned over somewhat easily so I am feeling a bit better. Next I drained the oil pan again getting another half quart of gas/oil just 1 day after draining the pan completely so there was still some fuel in the cylinders that is leaking down. I wanted to be able to spin the engine more so I refilled the oil pan and cranked it pretty good before putting the plugs back in. Time to tear into the carb...

TreeFiddy

For that much fuel in the crankcase, would seem to be mech pump failure but as noted above this would not explain fuel in the bores. Unlikely as it seems, it has to be coming from the top.

All that come to mind carb-wise are ruptured power valve, stuck open float valve, ruptured accelerator pump diaphragm, or loose jet. However I would not think any of these could dump this much fuel before you noticed, it would have been running extremely badly or not at all.

Black 84 Z

Today I went ahead and just replaced the power valve and fuel pump. Since I had the carb apart I messed with the floats and hand pumped the accelerator pumps which both shot fuel out so they should be OK. I got everything put back together and checked the oil (looks alright), but when I go to turn it goes slow enough that it won't fire and I can hear it squeaking from the lack of oil and the fuel that was in the cylinders (I hope). How can i lube the cylinder walls so that it can spin more freely and not break anything??

88PontiacT/A

Get a small syringe, pipette, or something similar and sqirt a little light weight oil or marvel mystery oil (teaspoon or so) in thru the sparkplug holes and then turn it over with no plugs in it for a few revolutions. I would put a little section of hose on the end of the syringe so that I could run that up into the combustion chamber and then dispense the oil into the cyl towards the inner wall (closer to the cam side) of the cylinders, that way when gravity takes over, the oil will run down around the piston and towards the exhaust side. (If you just put the oil straight into the plug hole, it may not get any lubrication on the cam sides of the cyl wall since that side of the piston top is higher) Then put the plugs back and try to start it again. Dont go too crazy with the oil or it might foul the plugs before you can get it started.
John C.

Black 84 Z

Success!! As it turns out the battery was a part of the problem as it was completely shot this morning. Got it replaced and did just as described above with the oil to get it spinning easily. Put the plugs back and sprayed a small amount of starter fluid in the carb and it fired up pretty easily, of course I had to keep touching the gas to keep it going as it burned up the oil left in the cylinders. Tomorrow it is new plugs and wires, change oil, and tune the carb again.

88PontiacT/A

Glad we could help you get it running again!
John C.