HELP with fuel flooding problem please, stock 6 with Webers-WCC trip in Doubt Options

[Porsche Rescue]

Carb on right bank flooding badly. After turning off engine I can watch fuel pour into the throttle bores, literally forming a pool on top of the butterfly. First time it was over cyl. #3, then most recently over 1-2. Fuel was coming up the air cor. jets . It acted like the system was pressurized. After draining bowl, removing needle assembly, blowing it out and checking float level with gauge all is well. But I don't think I have truly fixed the problem.
I was planning to leave tomorrow for the 1000 mile trip to WCC.

After a night of tossing and turning, I have a theory. Fuel pump is likely the 35 year-old original. Could the valve or whatever that allows excess fuel to return to the tank be the problem? The fuel pressure spec is only 4.2 lbs. If the return were not working it seems to me a much higher pressure would develop. Any experince with this out there?

[rhodyguy]

get the pump from the black 6 at camp and we'll try it this afternoon. i can't believe/handle this one jim. what about the tangerine 4?

k

[d914]

typically there is no return on a carb'd car. Needle valve is most likely the culprit.

[rhodyguy]

i'm not sure of the cyl arangement on a 6. is this all on one side of the engine?

k

[Porsche Rescue]

This is an original stock system. Pump looks just like the 4cyl. FI pump. Three connections, one from the tank, one to the carbs and one return to tank.

Good idea Kevin, but I am quite sure the black car would have a different pump since it is a conversion. Not sure though. As soon as parts places open I am going to see if I can source a new pump. Only small chance there is one in the city. Bought one 3 years ago locally, $300+.

[rhodyguy]

if you can, with the key in the on position, unstarted, is fuel running in? with the air filter off and carefully look down the throats. on my exploded parts diag #70 is the pump jet. is fuel coming out of those as well? i'll bring the thomlinson book with me. how does the car idle jim. fine, ragged, snap or pop? any other symptoms? on those cyl does one idle idle mixture screw have no effect? i hate the smell of gas in the morning.

k

[Porsche Rescue]

I could see fuel flooding in while looking down the throats AFTER engine/pump were off! I am going to hook up a fuel pressure gauge this morning and see what it reads.
This all started a few days ago when I left the key on with the engine off, running the pump for about 10 minutes (stupid) while wiring the radio. It shouldn't overpower the float needles unless they are stuck open or unless there is too much pressure. I am thinking too much pressure.

[Eric_Shea]

Jim,

The pump should be good... they really don't fail. HOWEVER: it gummed up while sitting at Troy's for the restoration. It literally wouldn't turn. I removed it and ran an entire can of carb cleaner through it and (I thought) it took care of the gum issues. There is a bypass circuit in the nose of the pump. My guess is there was some gum in the pump body and it's lodged itself in the bypass circuit.

Remove the pump. Remove the nose assembly (4 bolts), and check to see if it's stuck. If it's stuck it could hold pressure in the line and allow the gas to "push" it's way into the carb as described.

Good luck.

[Root_Werks]

Your fuel pump is delivering fuel, so that is probably not it. Don't waste your time on that. If your pump was delivering too much pressure, both carbs would be overfilling. That is what is happening here, you are overfilling your bowls. I have run into this a few times on 914-6's and 911's. So far, they have ALL been an ill set float, or in your case, I sticking or bad needle valve.

Pop the top of that carb off and just replace both needle valves. I would bet money your leak stops. Been there, done that quite a few times. It will be a good time to double check the float levels.

Don't take that fuel pump out yet.

Needle valve, check those needle valves. Dang, I probably have a few spares too. (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)

[Trekkor]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

Mine did, ( sometimes still does ) the same thing.
Same cylinders, too (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif) .

I still need to swap out the valves as well. Really quick and easy.
What, 15-20 minutes, with float level adjust?

KT

[Porsche Rescue]

Where does one get new float needle assembly? Can they be purchased alone or is it necessary to get a kit?

After talking to Eric I am going after the pump as well. But it wouldn't hurt to deal with needles as well.

[Root_Werks]

QUOTE (Porsche Rescue @ Apr 20 2005, 07:10 AM)

Where does one get new float needle assembly? Can they be purchased alone or is it necessary to get a kit? After talking to Eric I am going after the pump as well. But it wouldn't hurt to deal with needles as well.

They should come in a carb tune up kit. OR, you could probably get a kit sent next day from GPR, I think they are the closest to you.

1-800-321-5432

I was thinking Gary at Parts Obsolete, but he doesn't really do the 6cyl stuff. But he is in OR. I don't have his number handy. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

[Trekkor]

Pssst...hey, buddy...it's not the pump. (IMG:http://www.914world.com/bbs2/html/emoticons/lol2.gif)

I'm running a brand new Holley Red at 3.5 psi.
i have the same symptoms. You have a mist that appears in the passenger rear barrel that condenses into a puddle on top of the butterfly. It looks like a ton of fuel, but it's less than an once.

Sometimes it drip drips out of the accelerator jet.

I adjusted the float height with the engine running.
Maybe I should do it with just the pump.

KT

[campbellcj]

Sounds like a stuck/clogged needle to me; BTDT. Sometimes you can tap on the brass banjo bolt thingie and free it up w/o removing; otherwise IIRC you ideally want a 15mm flat-faced 5 point socket to get the best bite since it is a very shallow fastener.

[sixnotfour]

QUOTE

Remove the pump. Remove the nose assembly (4 bolts), and check to see if it's stuck. If it's stuck it could hold pressure in the line and allow the gas to "push" it's way into the carb as described.

This IS a real problem with the Factory Pump, My Yellow Six had this Problem ,Dont rule it out.

It was also a prelude to rusty tank problems. For me anyway. (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

Pressure gauge easy. Good Luck (IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif)

[Porsche Rescue]

Took pump out and inspected, cleaned. It looked ok. Problem is solved for now and I'm heading south this morning. One of those things which are fixed but don't know why. Causes me to suspect it will return. Thanks for all the help.

[Eric_Shea]

Good luck on the trip (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

(she'll treat you well... I think she likes you.) (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[Cap'n Krusty]

QUOTE (d914 @ Apr 20 2005, 05:32 AM)

typically there is no return on a carb'd car. Needle valve is most likely the culprit.

914/6s had a return system, as did 2.2L 911Ts. The Cap'n

[d914]

well, I knew that there could be and or should be a return line......I was pretty close with the neddle valve guess (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) though...

[Thorshammer]

Stop,

It's not the pump. Are you sure all three carb throats are overflowing. or are just two. If it is just two then the needle valve is the problem, it is common for these to stick. Leave the carb on and remove the 16mm brass plug on top of the needle and seat, don't remove the carb as these muthers are tight. After you get it off, a 14mm socket will remove the needle and seat, clean it with some contact cleaner on a paper towel and see what comes out, they are usually just sticky. Reinstall it. then remove just the top of the carb. all 8mm nylok nuts. Be careful not to drop anything, you will have a bitch finding replacements. I doubt both floats are misadjusted, but I guess it is possible. It is more likely that the needle ans seats are sticky, this is possible if the car has sat for awhile.

Good luck,


Erik Madsen