Printable Version of Topic
Click here to view this topic in its original format
914World.com _ 914World Garage _ Carbs
Posted by: cpavlenko Oct 3 2019, 01:59 PM
I built my 1.7 to a 2.0 with 2 Weber 44s. When I get back from a good cruise and park it in garage, after bout 7 mins later I here a gurgling from the carbs. Fuel dripping on butterfly's. Stinks up my 3 car garage. Me and my mechanic are doing different things. The last thing I tried was pulling a nipple I put on the expansion tank where the charcoal canister line went to the expansion tank. Did another 50 mile cruise, and parked it in the garage and after 7 mins nothing, then a little drip. It was about 3/4 better taking the nipple off. Soooooooooo, what is going on, I'm confused and help would be thankful.
Posted by: Superhawk996 Oct 3 2019, 03:15 PM
I see you are in AZ. Are you running it hot and then immediately parking it? That could be causing some fuel boiling? Have you tried a few minutes of idle cooling before you shut down to see if that affects it?
Do you have the fuel line entering the carb from above the level of the carb?
Sort of sounds like it could also be leaky float needle valves and the fuel is draining into the carb bowl via gravity. High fuel bowl level can then cause a bleed over into the carbs. Fuel line should enter into the carb body from below the carb. Make sure that as your fuel line crosses over from one carb to the other carb, that you aren't routing that crossover line higher than the carb.
I've seen people loop it up though the loop for the trunk torsion bars. This puts it higher than the carb and susceptible for gravity drain back if a float needle is worn.
Posted by: John Oct 3 2019, 03:46 PM
Do you have any insulators between the heads and the manifolds? Back in the day, when I used carbs on a 4-cyl, we used to use a thick insulator between the head and the short intakes. This hard plastic block was supposed to (and seemed to) keep the carbs from heat soaking and boiling the gas remaining in the float bowls.
Not sure if they still have those insulators or not. I haven't used carbs in years, but I still have a set of them in a box somewhere. I converted that engine back to stock FI before I converted to a 3.2 six.
Posted by: johnhora Oct 3 2019, 06:08 PM
phenolic spacers between the manifold and carb
http://www.914world.com/bbs2/lofiversion/index.php?t197562.html
http://forums.pelicanparts.com/porsche-914-914-6-technical-forum/292755-1-7l-intake-phenolic-gasket-thickness.html
Posted by: cpavlenko Oct 3 2019, 07:40 PM
I see you are in AZ. Are you running it hot and then immediately parking it? That could be causing some fuel boiling? Have you tried a few minutes of idle cooling before you shut down to see if that affects it?
Do you have the fuel line entering the carb from above the level of the carb?
Sort of sounds like it could also be leaky float needle valves and the fuel is draining into the carb bowl via gravity. High fuel bowl level can then cause a bleed over into the carbs. Fuel line should enter into the carb body from below the carb. Make sure that as your fuel line crosses over from one carb to the other carb, that you aren't routing that crossover line higher than the carb.
I've seen people loop it up though the loop for the trunk torsion bars. This puts it higher than the carb and susceptible for gravity drain back if a float needle is worn.
I'm in Northern Arizona, and it's been in the low to med 70's.
Posted by: cpavlenko Oct 3 2019, 07:41 PM
I see you are in AZ. Are you running it hot and then immediately parking it? That could be causing some fuel boiling? Have you tried a few minutes of idle cooling before you shut down to see if that affects it?
Do you have the fuel line entering the carb from above the level of the carb?
Sort of sounds like it could also be leaky float needle valves and the fuel is draining into the carb bowl via gravity. High fuel bowl level can then cause a bleed over into the carbs. Fuel line should enter into the carb body from below the carb. Make sure that as your fuel line crosses over from one carb to the other carb, that you aren't routing that crossover line higher than the carb.
I've seen people loop it up though the loop for the trunk torsion bars. This puts it higher than the carb and susceptible for gravity drain back if a float needle is worn.
I'm in Northern Arizona, and it's been in the low to med 70's.
Posted by: cpavlenko Oct 3 2019, 07:47 PM
I see you are in AZ. Are you running it hot and then immediately parking it? That could be causing some fuel boiling? Have you tried a few minutes of idle cooling before you shut down to see if that affects it?
Do you have the fuel line entering the carb from above the level of the carb?
Sort of sounds like it could also be leaky float needle valves and the fuel is draining into the carb bowl via gravity. High fuel bowl level can then cause a bleed over into the carbs. Fuel line should enter into the carb body from below the carb. Make sure that as your fuel line crosses over from one carb to the other carb, that you aren't routing that crossover line higher than the carb.
I've seen people loop it up though the loop for the trunk torsion bars. This puts it higher than the carb and susceptible for gravity drain back if a float needle is worn.
I'm in Northern Arizona, and it's been in the low to med 70's.
Posted by: cpavlenko Oct 3 2019, 08:09 PM
I've also heard of putting on/off switch for fuel pump. Switching to off before turning power off. In other words turn pump off and wait tell fuel runs out, then power down the 914.
Posted by: cpavlenko Oct 3 2019, 08:31 PM
I see you are in AZ. Are you running it hot and then immediately parking it? That could be causing some fuel boiling? Have you tried a few minutes of idle cooling before you shut down to see if that affects it?
Do you have the fuel line entering the carb from above the level of the carb?
Sort of sounds like it could also be leaky float needle valves and the fuel is draining into the carb bowl via gravity. High fuel bowl level can then cause a bleed over into the carbs. Fuel line should enter into the carb body from below the carb. Make sure that as your fuel line crosses over from one carb to the other carb, that you aren't routing that crossover line higher than the carb.
I've seen people loop it up though the loop for the trunk torsion bars. This puts it higher than the carb and susceptible for gravity drain back if a float needle is worn.
Yes, I've tried letting engine idle before shutting down, didn't help. As I said when I removed the plug on expansion thank, it was much less, couple drops but no gurgling of fuel. I'll post a picture of the area that helped with about 3/4 less fuel dropping down on butterflies.
Posted by: cpavlenko Oct 3 2019, 08:44 PM
Here's some pictures. 2 pictures show plugged and unplugged on expansion tank. That made it a lot less dripping to butterflies on carbs after a good 50 mile run. The other pics show fuel lines and pressure regulator which is at 3.5 lbs. 
Posted by: cpavlenko Oct 3 2019, 09:10 PM
Here's some pictures. 2 pictures show plugged and unplugged on expansion tank. That made it a lot less dripping to butterflies on carbs after a good 50 mile run. The other pics show fuel lines and pressure regulator which is at 3.5 lbs.
More pics.
Posted by: cpavlenko Oct 3 2019, 09:44 PM
Here's some pictures. 2 pictures show plugged and unplugged on expansion tank. That made it a lot less dripping to butterflies on carbs after a good 50 mile run. The other pics show fuel lines and pressure regulator which is at 3.5 lbs.
More pics.
Posted by: cpavlenko Oct 3 2019, 09:48 PM
Here's some pictures. 2 pictures show plugged and unplugged on expansion tank. That made it a lot less dripping to butterflies on carbs after a good 50 mile run. The other pics show fuel lines and pressure regulator which is at 3.5 lbs.
More pics.
Attached thumbnail(s)
Posted by: MikeM Oct 4 2019, 09:15 AM
Hello...I had the exact same issue with my Weber 44's.
We installed the spacers between the head and the intake AND between the intake and the carbs!! Adjusted the floats and all is good!!
Mike
Posted by: cpavlenko Oct 4 2019, 09:38 AM
Sorry for the multi post guys. Was doing uploads on my tablet. I have better luck with my laptop. So from here on, laptop. Confounded technology, lol...
Posted by: michael7810 Oct 4 2019, 10:56 AM
I've also heard of putting on/off switch for fuel pump. Switching to off before turning power off. In other words turn pump off and wait tell fuel runs out, then power down the 914.
I did this for a similar problem plus to use as a theft deterrent. I have not parked it in the garage since the mod but from what I can tell it helps reduce the fuel smell from the carbs. The other benefit is I can mess with my Bluetooth distributor programming without the fuel pump running while the ignition is on
Posted by: Superhawk996 Oct 4 2019, 11:22 AM
All the fuel line routings look sensible.
The plug on the expansion tank is an odd clue. It suggests the fuel tank is building pressure after shutdown and putting some slight pressure on the fuel line but honestly I can’t see how that would overcome the float needle valves.
Are you absolutely sure the float levels are adjusted properly?
As others have stated insulators can’t hurt. I ran my Weber’s direct to the head with only a standard gasket and never had any problems but I’m in the Midwest so cooler temps and no elevation.
Posted by: cpavlenko Oct 4 2019, 12:32 PM
Yeah, the gurgling I here must be heat related. Looking for phenolic spacers to anticipate the heat going to carbs. If not found, switch for fuel pump.
Posted by: yeahmag Oct 4 2019, 03:34 PM
Stock intake gaskets (which are a spacer of sorts) should be a good bet. I run them on the autocross car with carbs.
Posted by: porschetub Oct 5 2019, 01:54 PM
Have you tried adjusting the fuel pressure to say 3 psi ,looks like you have the regulator screwed right out from what I can see.
You are using the correct model regulator ? the one you want is Holley 1 to 4psi model 12-804
I bought a aftermarket Weber kit some years ago and the carb flooded even @ very low pressure,had a no brand needle and seat so I replaced it with a genuine Weber one and problem solved.
Good luck.
Posted by: cpavlenko Oct 5 2019, 08:50 PM
OK, if I put a phenolic spacer between manifold and carb, it will raise the carb to where it will not allow the engine hood to close with rain tray. The more I think about on/off switch for the fuel pump the more I'm liking that solution. Besides, haven't found any spacers for type 4 engine. I'm assuming it will take bout 30 secs for car to run out off fuel to carb before turning key to off position.
Posted by: yeahmag Oct 5 2019, 09:17 PM
Take the rain tray off. You are fixing the symptoms with the fuel pump, not the problem.
Posted by: cpavlenko Oct 5 2019, 09:48 PM
Take the rain tray off. You are fixing the symptoms with the fuel pump, not the problem.
Yes, ur right. Do have any ideal where to get the phenolic spacers between carb and intake manifold.
Posted by: yeahmag Oct 5 2019, 10:02 PM
The stock part will for the FI runners should do the trick.
Posted by: MikeM Oct 6 2019, 08:05 AM
Triangle Auto Supply in Yakima, Washington....
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)