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57 wrochester quad overfuel update

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uscgret

Member
"Hi fellas, I'm at wits en

"Hi fellas, I'm at wits end. My 86 Bayliner is still overfueling. New everything. Dist, coil, wires, plugs, fuel pump, a/s valve, carb, etc etc. I'm getting trace amounts of gas in the oil pan, and the plugs are fouling. You can smell raw fuel through the exhaust even underwater, and pulling the breather hoses off the valve covers you can smell raw fuel when it's running. I can turn the idle down very low, adjust both mixture screws all the way in and the engine won't change pitch. (2nd carb and fuel pump). Same symptoms.
Question 1: If my fuel pump is putting too much fuel to the carb, would it do this and if so what psi should my mechanical pump be putting out.
Question 2: If my cam is washed (I have 150 PSI on all 8 cylinders compression) would it do this?

It idles perfect and runs fine until the plugs foul.

Focus on the problem that I am getting too much fuel in the cylinders to cleanly burn and I can't adjust the carb at all!! Seems to me overpressure to the carb?!! Could I have been handed the wrong psi replacement pump. The original had the same symptoms but I disected it to see if it was a causal factor and the diaphragm was fine.
My spark is tremendous, everything from tank to carb is new, all electrical is new, compression perfect! Everything tuned to specs. Same problem.

300 hours on this boat. Any ideas.........

El Pescador, my email addy is [email protected] I'll gladly pay you for advice. I'm in Michigan, summers closing out and this is the 3rd year I haven't been able to run. My wife thinks the boat is the bank that only accepts deposits at this point and she's definitely going to come uncrimped if she finds my reciept file on this boat when I tip over...lol.

Great forum, everyone's wonderful, please....help."
 
"Your mechanical fuel pump sho

"Your mechanical fuel pump should be putting out 3-5 PSI.

Is the Quadrajet new, used, or a new rebuild?

Ensure that your float is not stuck. I would tear down the carb. and inspect everything within. Quads are very straightforward. A stuck float will dump fuel into the intake, as I am sure you probably know. Before you do this though, take a ball peen hammer and give the carb a nice 'whack' on all sides. This may release the float.

Are all eight plugs equally fouled?

With the engine idling look down the carb. Is fuel coming out of the accelerator pump, or between the body?"
 
"Denny, looking at some of you

"Denny, looking at some of your old posts it seems to me you have had this problem for a long time. And if I read you correctly, you said that you have installed a new fuel pump and also a new carb but the problem persists. You also mentioned that when you go underway and go about a 1/4 mile, then the plugs foul and you get a measurable amount of gas in the oil pan.

1) The first thing you may want to do is to make sure you have the correct fuel pump installed, and that it delivers the correct pressure (6-8 psi). For this, you may have to attach a T fitting to the fuel delivery pipe and attach to it a pressure gauge.

2) If the above is OK, make sure the pump is in good condition and it does not have a perforated diaphraghm. The pump should have a fitting with a plastic hose attached to it (the plastic hose ends in the carb flame arrestor. Make sure the plastic hose does not have gas on it.

If the above is OK, and if <u><font color=""ff0000"">all</font></u> the spark plugs are being fouled, then I see only two possibilities: the carb is overflowing, or faulty ignition. The first possibility seems odd as I believe you said you used a new carb (two carbs suffering from the exact same problem seems unlikely). I also assume that you have verified that the ignition wires go to the correct spark plugs (1-8-4-3-6-5-7-2 for standard rotation; if you haven't verified this, you may want to do it now). Now, to eliminate most ignition problems, have you followed my advice in another post and installed a Pertronix electronic ignition module in your distributor? If not, I strongly advise you to go that rute. And when (if) you do so, you may want to further install a 40000 V coil and remove the ballast resistor (you will not need it any longer).

I have a 350 with a 4-barrel Holley carb with automatic choke and a Prestolite distributor with a Pertronix electronic ignition kit. It runs very well, and so should yours (even if you have a Rochester Quadrajet)."
 
"Thanx for the replys fellas.

"Thanx for the replys fellas.

El, I ordered the pert last post and got the flamethrower to go with it, hasn't arrived as yet. Firing order verified 100 times, all plugs seem equally fouled. Tapped the carb as previous post recommended no change. Fuel is coming out of both nozzles equally.

Fuel pressure check tommorrow (land surveying these days is like a sale on vodka in tennessee (no offence), will advise, but hose is clear and when I put it in my vaccuum gauge mouth it pushes and pulls the same rate, diaphragm checks out well.

How about the washed cam?????? I think not. Your thoughts"
 
"Denny, to me the fuel pump ma

"Denny, to me the fuel pump may be putting too much pressure and making the carbs overflow, or something else inside the carb is causing unmetered fuel to reach the cylinders. I cannot see other reason for so much fuel flooding the intake manifold to the point of ending in the oil pan. I assume the engine must be running like a dog."
 
"El,

Idle and runup to 4600

"El,

Idle and runup to 4600 is like a champ, run it for 20 minutes as such, then wot and 20 second crank to restart, then same game.

Denny"
 
"Hook an inline spark tester t

"Hook an inline spark tester to one of the plugs and run the engine. When it starts running poorly take a look at the spark. Is it blue, or orange?"
 
"Hi Denny. If you have read ma

"Hi Denny. If you have read many of my recent posts you know that I have been dealing with the Weber carb people and they have passed on some good advice. I asked the engineer about an inline fuel pressure regulator and he said it was a good idea in and of itself. So, I bought a "Mr Gasket #9710 Fuel Pressure Regulator" and installed it. I believe my carb float chamber was 'tipping', or overrunning causing an excessively rich mix and the regulator has cured that. It's adjustable from 1-5 psi and cost about $36 Cdn. They are available with higher psi ratings. Worth a try and it would eliminate one possible cause, that of too high fuel pressure at the carb.

fwiw...Tom

As an afterthought, the Weber engineer also said that he'd seen fuel pumps with our psi ratings putting out 5-6 psi more that the max. Again fwiw."
 
"Following El's advice,

"Following El's advice,

Just bought the flamethrower 40k coil and pert ignition conversion. I raped the UPS guy for them when he tried to deliver it to my neighbor. I'll be out on the boat at sunup installing it. I'll post the results. I sure appreciate everyones help on this matter. Your all great. Checked my psi on the fuel pump. 6 pounds........ This is the last part I'll buy for the boat. (If anyone needs a 2X large brown uniform, contact me)

Denny"
 
"Installed the elec ignition a

"Installed the elec ignition and 40k 1.5 ohm coil. Had to use the ballast resistor for some reason. Boat is doing the same thing. The only thing not new at this point is the block, intake and heads. I'm going back to the carb as the issue even though it's the 3rd one. I have to believe the float is set wrong allowing fuel to bypass. My engine sits at a 5 degree nose down angle in the boat which may play a part in the float setting. Nothing to lose at this point by pulling it apart and checking the position of it I guess even though it's new. Any and all ideas or advice are appreciated, you've all been a great crew."
 
"Denny, you don't need to

"Denny, you don't need to use the ballast resistor witht he 40KV coil. By doing so you will get a reduced voltage and poor spark. I wouldn't be surprised if this is what is causing your trouble. I don't have one on my 350 and it runs like a charm.

Gordon, the specs in Seloc regarding fuel pressure state 6-8 PSI."
 
"I have installed a 1.5 ohm Fl

"I have installed a 1.5 ohm Flame Thrower coil and no resistor. Mine does not get red hot, not even so warm that I cannot touch it. The 3 ohm coil is designed for 4 cylinder engines. See page 3 on this link.
http://www.pertronix.com/catalogs/pdf/ptx/2007/ptx07_coil.pdf

Also, look at this link. My engine came with an electronic ignition distributor from factory (not a Pertronix, but now I am using Pertronix). As you see, there is no resistor in the wiring for the coil, only for the alternator.

http://www.volvopentastore.com/ELECTRICAL_EQUIPMENT_AND_INSTRUMENTS_AQ311A/dm/ca rt_id.220807850--list_time.1220730232--session_id.208839500--view_id.316121"
 
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