Holley 4160 dripping primary main nozzle |
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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Posted: August-01-2009 at 11:56pm |
Hey carb gurus,
I seem to have developed an issue with my carb. I'm having idling issues, and took the flame arrestor off to take a look. I noticed the port side primary main nozzle is dripping fuel down the bore at idle from around the booster venturi. The starboard side is not. This corresponds to my issue, the boat will start and idle cold but once warm it seems to load up and dies. It runs well off idle, but dies once I close the throttle. What would cause fuel to drip from the main nozzle? I'm gonna peruse my Haynes manual and see what it says. Thanks in advance, Anthony |
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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After some research on the 'Net, I found it could be a leaking power valve. The Advance Auto Parts has them for $10.
The rebuilder put a 8.5" Hg power valve in my carb. Should I change it to a 2.5" Hg power valve? |
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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I think many guys around here put the 6.5'' PV.
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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Changing the PV should necesitate a jet change, too, right?
According to the PCM service manual, the 4160 with a 8.5 PV uses #582 jets. If I change to a 2.5 PV, should I replace the jets with #622 to flow a little more fuel since the power circuit will come in later? |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3359 |
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NO you are getting too crazy. One doesn't jet for their power valve. the PV does not meter the fuel.
8.5 is too early on the PV, choose a 5.5 or 6.5. Since you have no idea the ID of the PVCO's in those examples you mention, one cannot make the inferrence you were trying to do. If the PV was entirely blown, it should still not drip at idle, there is not enough airflow across the main ventury. The symptom would be too rich and smokey at 10-25 mph I think your problem is one or both of the primary idle fuel bleeds is still clogged, requiring the idle to be upped too far so its running off the transition slots, I've seen this cause the main ventury to drip. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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Ok. If you don't ask the silly questions, then you end up doing silly actions. Not attempting to provoke a urination competition, but the jets and power valve do interact to some degree under high load, low vacuum conditions. The whole idea of the power circut is to allow you to jet lean, and have the power circuit add fuel when you need it.
By "ID of the PVCO" are you meaning "inside diameter of the power vavle channel orifice"? I was looking at the PCM service manual hosted in the CCF reference section for a list # 7163 carb. It gives power vavle and jet specs. I am by no means a carb expert, nor do I play one on TV. Thanks for your reply, you probably saved me from my own ignorance. Anthony |
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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I just saw the rest of your response...I did run the thing out of gas, and could have sucked up some trash from the bottom of the tank.
I've sent a message to my rebuilder and he seems to think contamination as well. |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3359 |
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Yes, You're sortof getting it.
But, the there is no difference in flow between a 2.5, 6.5 or 8.5 PV is when at high load, low vacuum. ( as long as its less than 2.5") My main point is one sets the mains (plus PVCO size) for full throttle. doinking with the mains for when choosing your PV opens is a crutch for improperly size PVCO's, and instantly gaurateed to eff up jetting at WOT. If you have a marine carb ( a heavy truck 4150G), you are assured that holley set the PVCO's to the proper half the ID of the mains, for 25% more flow (unlike many 'universal' holley carbsthat were set too fat and belch smoke). Setting the PV to when the engine needs the extra fuel with PV is a great way to fine tune the performance, But the mains are set and fixed using different methods and should not be adjusted to the PV. Jets are and early step in tuning, PV one of the latter. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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Thanks for your reply.
A little knowledge and a set of wrenches can be a recipe for disaster. So it sounds like some carb cleaner and compressed air are in order. |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5778 |
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To add to GottaSki's comments on Power valves. Even with a higher number PV like a 6.5 you'd be surprised how little you use it. Just for grins hook a vacuum gauge to your motor and go for a ride. On my boat the vacuum doesn't drop low enough to open the PV until over 4000 rpm so it's not even a factor in your basic carb setup.
If you have the stock carb that came on the boat I'd set the A/F properly and leave the jetting alone unless you can read plugs. |
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You can’t change the wind but you can adjust your sails
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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I guess I'm going to spend some quality time with my metering block, a can of spray carb cleaner, and the air compressor this evening. Worse comes to worse, Chuck at carburetors and more said they will tear it down completely and fix it for $100 if I can't.
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almabes
Senior Member Joined: March-20-2008 Location: Acworth GA Status: Offline Points: 263 |
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Well, it looks like I may have fixed my carb, as Joe Cocker says "With a little help from my friends". I'm lucky enough to have a neighbor that enjoys tinkering with anything that burns fossil fuels with cylinders in a V configuration. I took the primary bowl off and handed it to him. He took out the float, and cleaned the needle and seat out. He put it all back together, handed it to me. I put it all back together and fired her up. It idles like a champ now. No drips.
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rmm025
Senior Member Joined: July-20-2009 Location: West Monroe, LA Status: Offline Points: 148 |
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I was coming on here tonight to tell you the same thing. I started having the same problem this week, and fixed it by cleaning out my needle and seat. I didn't have the guts to tear it out though, just a few itterations of carb cleaner and air with the secondary tube plugged so that the cleaner and air went throught the needle and seat.
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gjsullivan
Newbie Joined: November-08-2004 Location: Hillsboro, OR Status: Offline Points: 13 |
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It has been a few years on this but I had the same problem with dripping on port side at idle. And thought this may help someone.
At spring start up I did end up running it out of fuel. I rebuilt the Holley 4160 carb last year and it ran fine. This year it ran fine until I ran out of fuel and then I Had the dripping at idle. witha really rough idle. Pulled the bowl and metering block used carb cleaner and compressed air on all the parts and holes. . Reassembled and had same problem. Took it apart again This time I checked the screen filter where the fuel line connects, it was open on one side. So I assume some crap got in even though I have a spin on fuel filter. Fixed that. The power valve and accelerator pump were fine. I pulled the float and held it under water, no leaking. The needle looked fine but I had kept the old ones from the rebuild and decided to try one of them. Reassembled and it ran fine, no dripping at idle. So the moral may be check/clean and then double check/clean |
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67 Mustang, 90 Sport
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4127 |
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Or pay more attention to your gas gauge.
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gjsullivan
Newbie Joined: November-08-2004 Location: Hillsboro, OR Status: Offline Points: 13 |
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Thanks, I was running it on the hose working on it in the side yard. The gas gauge or sender is the next item to fix. That decided to flake out.
By the way took it out this weekend pulling kids for the Church youth group. Ran great. In fact idled so smooth I had to keep checking the tach to make sure it was still running. :-) |
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67 Mustang, 90 Sport
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