High altitude jets for BFN Carb |
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Tankwagon
Newbie Joined: June-04-2018 Location: Park City, UT Status: Offline Points: 9 |
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Posted: August-17-2018 at 11:48am |
Can anyone tell me the model number of the Holley carb that should be on my 1989 Barefoot Nautique so I can get the right jets for it?
I don't have access to the boat right now to look myself. It is a stock 330HP PCM 454 engine with Holley 4bbl carb. I am now operating it at most often at approx 6,000 ft above sea level (Jordanelle Reservoir in UT). and other mountain lakes ranging from 4,000-7,500 ft. Also- what is the recommended timing advance for the stock distributor, assuming I go 3 jet sizes smaller? Thanks! |
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JP 1989 BFN Previous- 1967 Ski Nautique |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Calling JQ!
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1989 Ski Nautique 2001
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Tankwagon
Newbie Joined: June-04-2018 Location: Park City, UT Status: Offline Points: 9 |
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Ok- I was able to get some pics of the carb. It's a List #80262 which means its a model 4160, 650CFM.
It looks like the two main jets are easy (122-74). But the secondary metering requires swapping out a metering plate that I cannot find the stock jetting specs for. Any ideas? Thanks! |
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JP 1989 BFN Previous- 1967 Ski Nautique |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10653 |
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What's the number stamped on the secondary metering plate?.
It'll be a 2 1 or 2 digit number like a 7 or a 10 or a 12 or any of about 40 or so different numbers. From that number you can determine the main hole size and the idle hole size. |
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Tankwagon
Newbie Joined: June-04-2018 Location: Park City, UT Status: Offline Points: 9 |
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I don't know yet. Still not at the boat. Just got someone to take a pic of the list number.
I guess I'll just have to wait 'till I can get back to the boat. I was just hoping to order the jets and metering plate I need first. |
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JP 1989 BFN Previous- 1967 Ski Nautique |
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Tankwagon
Newbie Joined: June-04-2018 Location: Park City, UT Status: Offline Points: 9 |
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Bonus question:
Do you think I'll need to change the accelerator pump cams and power valves too (for 6,000ft operation)? |
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JP 1989 BFN Previous- 1967 Ski Nautique |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10653 |
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Bonus answer
The Holley tech support people on the other end of the phone line can be pretty helpful That was meant for your question about the metering plate but it's also a good answer to you question of power jets and accelerator pump cams. They can probably tell you what metering plate it came with (maybe) |
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2843 |
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As KENO suggests, you may want to call the Holley help-line with your carb model and/or serial number. They can likely tell you what the stock configuration was.
I would look at dropping 2 to 3 jet sizes. Jets are cheap, so you can buy both. Start at 2 sizes down and see how things feel. Listen for knocking or detonation. Read your plugs after a couple of hours. If the mixture still looks a bit rich, then swap out to the next size down. You are correct that the Holley 4160 has no replaceable jets in the secondary, but rather a change-out of the secondary metering block. (This is why I like the QuickFuel carbs as both primary and secondary metering blocks have changeable jets as well as air bleeds) I know folks that have drilled-out the secondary block, but I would recommend caution, as you can't go back if you drill too big. Also, since you are looking to go leaner for altitude, then drilling out the secondary block really isn't an option. JQ |
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2843 |
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I'd tackle accelerator pump after getting the jetting figured out. If you are properly set up on timing and jetting, you can get a feel for hole-shot and if the accelerator pump needs to be tweaked. Hole-shot and bogging will give you the feedback you need. A good video on accelerator pump tweaking can be found HERE JQ |
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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Andrewracoon
Groupie Joined: April-23-2018 Location: Sandy Utah Status: Offline Points: 40 |
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Im also running a 454 here at jordanelle res. Im not sure on the jetting because I run an edelbrock carb, But i can tell you I set my timing exactly at 10 degrees and it runs fantastic. It advances to about 32 total and it runs perfect.
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2843 |
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Andrew...now just get that rear main seal changed out and you should be good-to-go.
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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