Anyone know how to re-jet a carburetor for altitude?

[sbouslog]

I know that this isn't a engine forum, but it's the only forum that I belong to. I just bought a boat with a carbureted 350 in it and have never owned a non EFI vehicle. The boat currently lives in Iowa but is going to finish its life here in Denver/Lake Granby/lake Mccanahey NB. Since these areas are all pretty different in altitude I figure that I need to learn to do this myself. Any advise you can give me (other than "don't take your guns on the boat because they tend to fall off and sink") would be great.

[10mm-man]

I know that this isn't a engine forum, but it's the only forum that I belong to. I just bought a boat with a carbureted 350 in it and have never owned a non EFI vehicle. The boat currently lives in Iowa but is going to finish its life here in Denver/Lake Granby/lake Mccanahey NB. Since these areas are all pretty different in altitude I figure that I need to learn to do this myself. Any advise you can give me (other than "don't take your guns on the boat because they tend to fall off and sink") would be great.

Pull jets / insert new ones.... Google it or go to Auto parts Store... Actually go to Auto Parts store with make an model of motor..

[Longnecktipper]

Rule of thumb is every 2,000 feet above sea level , drop a jet size . Do a google search for rejetting for reading material , then follow with a YouTube search for the same thing for the visual . Not to hard of a switch , some carbs are easier than others. Some Holley carbs can be fitted with quick change Jet kits . Makes it real easy once you figure out what jets work best.

[Ah Pook]

What kind of carb? Holleys are easy. Q'jets are more involved.

The last Holley 2300 375cfm I rebuilt was built at sea level and had #63 jets in it. I ended up using #53 or #54 jets at 8500'.

Figure on a couple of less pounds of vacuum for every 1000' in elevation gain too.

[Great-Kazoo]

You may need to change plug heat range.

[sbouslog]

It's the Edelbrock 1409. Here is a link. Thanks for all the info so far guys.

http://www.edelbrock.com/automotive_...c/marine.shtml

[bigshane]

Any advise you can give me (other than "don't take your guns on the boat because they tend to fall off and sink") would be great.

The forum members here have the WORST luck in this regard.

[GilpinGuy]

The forum members here have the WORST luck in this regard.

Really? You're kidding. I had this happen once recently myself.
(just a note for those profiling me)

[jerrymrc]

They make a kit for the AFB. Will come with the rods, jets and springs. If it was a Q-jet I could help ya out since I have done a bunch but the AFB is not that hard. http://www.edelbrock.com/automotive_...alibrate.shtml

Most Q-jets come with 72-74 and much of the cruse mix was in the rods. Later units had an adjustable APT. @ 6000' they seem to like 68's and then tune 26-29 steps on the rods. Power piston spring is very important for both the AFB and Q-jet.

[10mm-man]

Really? You're kidding. I had this happen once recently myself.
(just a note for those profiling me)