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4160 Jet size

Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=49865
Printed Date: March-04-2025 at 4:25am


Topic: 4160 Jet size
Posted By: brantb
Subject: 4160 Jet size
Date Posted: June-04-2021 at 12:31pm
I am going to be bringing my boat down to 600ish feet from 5k feet for the week of the 4th. I have not looked at the jet size that is in the carb currently, but based on how it runs i have to imagine it is right.

Anyways, anyone know what size jet should be in the carb for sea level? 4160 cab on top of a 99 351W with GT40P heads and alum intake if that matters.





Replies:
Posted By: KENO
Date Posted: June-04-2021 at 1:45pm
Got a list number for the carburetor? See the Red pointer in the picture Wink

That'll help you find the info you need, otherwise you probably could use # 66 main jets as lots of the marine 4160's used that size as their original calibration.

You should also think about the secondary metering plate and whether it's been swapped with something that has smaller holes than stock for high altitude operation. 
 




Posted By: Jonny Quest
Date Posted: June-04-2021 at 2:29pm
KENO is correct (he usually is...)  You really need to know the model carb you have so that you can determine the factory settings.  Once you know factory settings, you then need to determine what jets are currently installed.  You can do that by removing the fuel bowl on the primary circuit and carefully removing the jets.  If you don't have a fancy jet removal tool, a large flat blade screw driver works fine.  There is a number stamped on the jet -- usually.  The Holley 4160s that I'm familiar with don't have removable jets in the secondary circuit, so the carb will likely have the factory jetting in the secondary circuit (unless someone has drilled-out the metering block).

I'm in the SLC area and at about 4,400 feet of elevation.  My 1994 S.N. with a carb ran two jet sizes smaller (leaner) to compensate for the elevation change.  I've always used the rule-of-thumb of 1 jet size smaller (leaner) for each 2,000 feet of elevation.  As that is a rule-of-thumb, take it for what it's worth.  There are several lakes around me at 6,000+ feet of elevation and the carb set-up I used for 4,000 feet seemed to work reasonably well.  If you need some leaner jets, let me know as I've got 20 or 30 in my carb "box" that I can send you.

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


Posted By: brantb
Date Posted: June-07-2021 at 8:28am
 Looked up the number and it said it came with number 65 jets. JQ, do you have any that size? If not, i will order some up


Posted By: brantb
Date Posted: June-13-2021 at 2:25pm
Pulled the bowl and one jet. It had 652 stamped on it. I am assuming this is a size 65 jet, but can someone confirm. 

If it is indeed a 65 jet, i have been running rich up in CO for a few years now.


Posted By: KENO
Date Posted: June-13-2021 at 3:15pm
Out there in Colorado, you're not only high, you're rich too Wink

The 2 means it's a close tolerance #65 jet

Must mean you couldn't read the other jet?




Posted By: brantb
Date Posted: June-13-2021 at 3:28pm
I didnt bother pulling it. I thought they would be the same jet.


Posted By: KENO
Date Posted: June-13-2021 at 3:29pm
Originally posted by brantb brantb wrote:

I didnt bother pulling it. I thought they would be the same jet.

It should be


Posted By: Jonny Quest
Date Posted: June-22-2021 at 10:14pm
Originally posted by brantb brantb wrote:

 Looked up the number and it said it came with number 65 jets. JQ, do you have any that size? If not, i will order some up

I think I have a set of 65s

Send me a PM


-------------
Current
2003 Ski Nautique 206 Limited

Previous
2001 Ski Nautique Open Bow
1994 Ski Nautique Open Bow

Aqua skiing, ergo sum


Posted By: KENO
Date Posted: June-23-2021 at 6:39am
Umm............Brant already has a pair of 65s in the carburetor, since it apparently wasn't ever rejetted for higher elevations.



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