fuel not getting through the carb...

[domenic]

I have no idea how the electric fuel pump works...but, if it is like the manual fuel pump here is how I fixed the problem;
The manual pump, does not suck fuel, it pushes fuel into the carb. If there is air in the fuel line, the manual pump will not push the fuel.
Disconnect the fuel line between the pump, and the carb. Clear the fuel line of air between the tank, and the filter with a hand pump bulb. connect the pump to the carb, and start your A4.

MM should know if the electric pump is a sucker, or pusher.

Domenic

Up date The manual fuel pump does suck from the tank, and push to the carb. I have cleard all fuel from the tank to the pump. Have cleared all fuel in the pump. Hit the starter, and within seconds the engine is running. Air in the line does not stop the manual pump from sucking fuel from the tank. The fuel line from the tank to the pump is over six feet. If the electric pump has the same sucking power, you should have fuel in the carb.

[Dave Neptune]

Pump=displcemant

Domenic, if your pump is pumping it must be sucking! My mechanical pump has had no trouble priming my system ever. When changing filters I drain the lines once replaced a few strokes on the bail and fuel is in the bowl.
All pumps suck or they would not displace the volume to push it as you say.
How much the pump is capable of drawing fuel (sucking) is contingent on the condition of the check valves and the volume being displaced. Most pumps have a rating as to how high they will draw or the "suck rating" rated in inches or feet. Some will actually state the amount of draw as a vacuum value which is the draw or "suck" value. Once the pump is primed the pump will draw what it displaces.

The air in the system will be vented by the vent in the carb as the air gets to the carb. there may be a few air pockets left but there most always will be. You can see it in the clear type polishing filters and it has no affect on performance. With fuel injection you need to get the bubbles and air pocket to a minimum for consistant fuel preassure at the injectors.

Dave Neptune

[sailhog]

Okay.... so I now have fuel moving through the carb. The plugs are damp with fuel, but she's not turning over. She wont' even start with starting fluid. I thought I had the spark problem fixed.... apparently not. Tomorrow I'll be trouble-shooting the coil, distributor, plugs, etc. I'm ready for this engine to start. It's been 75 F here with 15 kt winds out of the SE.... Argh.

Thanks for everyone's help. Still requesting suggestions....

[roadnsky]

.... Still requesting suggestions....

You may already have this, but here's a checklist from Don you can run while you're troubleshooting...

[sailhog]

Thanks, Jerry. I'll be working through this thing as methodically as I can....

[domenic]

Domenic, if your pump is pumping it must be sucking! My mechanical pump has had no trouble priming my system ever. When changing filters I drain the lines once replaced a few strokes on the bail and fuel is in the bowl.
All pumps suck or they would not displace the volume to push it as you say.
How much the pump is capable of drawing fuel (sucking) is contingent on the condition of the check valves and the volume being displaced. Most pumps have a rating as to how high they will draw or the "suck rating" rated in inches or feet. Some will actually state the amount of draw as a vacuum value which is the draw or "suck" value. Once the pump is primed the pump will draw what it displaces.

The air in the system will be vented by the vent in the carb as the air gets to the carb. there may be a few air pockets left but there most always will be. You can see it in the clear type polishing filters and it has no affect on performance. With fuel injection you need to get the bubbles and air pocket to a minimum for consistant fuel preassure at the injectors.

Dave Neptune

With all respect Dave...and I do respect you. I know it sucks, and you know it sucks.
Ken Of Moyer Marine said, "THE PUMP DOES NOT SUCK...IT PUSHES FUEL TO THE CARB. IF AIR IS IN THE FUEL LINE, THE PUMP WILL NOT WORK."

I used a bulb to clear air from my line. A4 fires right up?

I had fuel in the bowl, and the pump would not push fuel to the carb. Took air out of the line, and the stupid system works like a dream. Now don't that suck?

[Dave Neptune]

The bail

It may not suck much but I have used the bail to prime my system many times when changing the fuel filter anually and when I do I drain the lines first.
The purpose of the check valves in the diaphram is to create suction on one side to draw in the fuel and then when moved the opposite direction the check valves push the fuel out. If it didn't suck how would the fuel get there?

Dave Neptune

[ndutton]

I'm wonderin' about the fuel pump itself. The whole point of the bail is for manual operation and decades ago that's exactly how we would prime new installations for testing - with the bail.

We'd pump, it would suck, the bail would stiffen (Stop that!!) and the engine would start.

So why won't yours prime itself? Bad check valve? Gasoline smell in the oil? Something not right here.

[Dave Neptune]

Problems

Sailhog, you stated that the plugs are wet with fuel so there must be fuel getting to the combustion chamber. If you tried a bit of "motor crack" and it didn't light one of two things or even both could be the culprit.
First before trying again cnofirm that you have spark at the plugs. you can disconnect one wire and stick a spare plug in the boot and give the beastie a spin. With the plug laying on the block so it is grounded you should see a bit of blue spark jump across the gap. If spark is confirmed and we have fuel and a bit of "motor crack" has been tried my gut tells me it could be timing.
How did the motor run before the present problem showed? If it ran OK and you have not moved the timing by twisting or removing the distributor all should be well. If you moved the plug wires around you will need to make sure they are in the correct order.
If we have all three it should run. Fuel yep it's there, spark(? the timing is correct or close), and compression (a thumb check should be fine) it should lite.
I am concerned about the choke and it functioning properly however motor crack will start almost anything.
Perhaps a historicle senario of how the problem started might help.

Dave Neptune

[sastanley]

right...what neil & Dave said..I was waiting before jumping on the bandwagon about the fuel pump. mine sucks just fine, and pulled fuel from a new tank, thru new lines and an empty Racor filter no problem using the bail. Vrooom!

Sorry this doesn't help sailhog with his no-start problem.

[sailhog]

Here's the latest on my endless starting problem....

I did another compression test: #1:85; #2:65; #3:85; #4:70.

I also check the spark at each plug as per Dave Neptune's directions, and they all appeared to have fire. While check #3, I felt a nice jolt of 12 volt running through the head.

I got her running on three different occasions for approximately 5-6 seconds, and then she quit, as though fuel starved. Working the throttle did nothing. I got her started using starting fluid on one of those occasions, but then she died.

Fuel puddles in the bottom of the carb after a few seconds of cranking, so the fuel pump would seem to be operating properly. Also, fuel would seem to be getting through the carb (I think).

I'm wondering if the problem could be as simple as bad fuel. However, I've changed it twice, and the interior of the tank appeared to be clean. Also, she doesn't start with starting fluid (except for one instance).

One last potential clue.... After trying and failing to get her started, she sometimes makes a strange racket -- like a clicking -- while the starter is attempting to turn her over. She doesn't make this noise at the beginning of the attempt, only at the end -- after about ten seconds of cranking....

Whoever figures out this mystery gets to date my wife. She's 45, pretty, good legs, great attitude.... Just trying to keep you all motivated!

[Kurt]

Hmm - that is definitely problematic compression on cylinders 2 and 4. May be time to try a Marvel Mystery Oil treatment on those cylinders to see if you can at least raise compression enough to get her started. The A4 can start with good compression on at least two cylinders, which you appear to have, but your compression values are likely contributing to your problem.

[ndutton]

I'm pretty sure the clicking is the electric fuel pump. Cranking her for a bit will produce enough oil pressure to close the safety switch and energize the pump.

I keep going back to your non-functioning choke. With my engine the choke needs to be fully closed to start (cold) but needs to be opened within about 5 seconds after starting. In post #7 you said your choke was non functioning, wired fully closed.

Somehow it needs to be opened pretty quickly after starting. How are you accomplishing this?

[sailhog]

Kurt,
The cylinders and valves are bathing in MMO as we speak...

Neil,
I'm not accomplishing this, as the wire is corroded to the housing.... I'll get on that. If it were the choke, why wouldn't it at least start and run for five seconds every time I tried to start her? Also, why does starting fluid rarely work when I have the choke open? Venture any theories?

Thanks to all....

[ndutton]

No, I'm short on theories. With the choke functioning it can be either confirmed or eliminated as the problem or as a contributing factor.

With a remote starter switch at the engine you can remove the cable and operate the choke by hand for testing purposes.


edit: Here's one theory

If it were the choke, why wouldn't it at least start and run for five seconds every time I tried to start her?

After initial start, five second run and die, could easily be flooded or at least way rich. Trying to restart with the choke still fully closed would aggravate the condition until fully flooded.