Author

Topic

Posted - Feb 15 2005 : 22:07:20

This is my last post in the old topic:

Posted - 15 Dec 2004 : 18:12:06
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All I can say is WOW!!!!!

I assume the setup reccomended for the Merc 350mag is Vortech. I know they have a higher V/E, but would that change the metering needed in the carb? Also I did find in the post reccomended metering for a std. 5.7, but for the same year, the Merc is rated 32hp less than my V/P (228hp Merc, 260hp V/P). I don't want to lose power, so should I pick the middle of the road? Looking at the chart, my delta is higher than a 350mag already!!! I guess I will go with .068 jet, .035 Primary. I know this is turning more into Carb Theory 101, than boating related, but I am a little confused on the theory of the 2ndry rods. The longer tip causes richer mixture sooner? Since I do 80% of my running below 80% throttle, does it really matter what tip I go with (S,M,L)? My current "av" rods are a medium tip, but way different in metering at 60% than the reccomended for the 5.7 Merc, by about .0025. Wouldn't the boat haver better mpg at this throttle w/ the CH instead of the AV due to the leaner mixture? However both of them are the same for WOT (.0567).

I guess really what I want to concentrate on right now it the primaries, as the secondaries are so darn easy to toy with. Does the 68/35 sound like it would still be too rich? I am also doing research on the operation of the power piston, and accelerator pump, to better understand how they work, and how to tell if what I have is correct or not.

This is already more info than I could have asked for, but by all means, if anyone has anything to add, lets hear it...

Thanks again guys.

-Shane

I want to order the parts so I can get my carb back together. I am still unclear if i should run the Merc setup, which was for an engine rated at 36hp less.

I want to get this done, and get this done right.

Also, can anyone reccomend a good place to get the parts? George>>> If you have them, or can get them, let me know, I will order ASAP.

Does anyone have the reccomened carb jetting for an AQ260?

-Shane

True friendship is like pee in your pants. Everyone can see it, but only you feel its true warmth.

Edited by - tr_guy79 on Feb 15 2005 22:12:09

Homeport: Elkton / Perryville MD

JohnSerb

RO# 14692

Posted - Feb 16 2005 : 06:39:39
Well, I've been looking at Carter/Weber/edelbrock carbs, and comparing primaries, secondaries, and metering rods, so understand some of your fustration. I decided no matter what, I can't be 100% sure that I'll pick the right combo for my engine. I will have to go through the tuning/adjusting phase. Here is what Dennis Moore recommends for a starting point for Q-jets on 305/350 SBC (from his Marine Performance book) Primaries: .068 or .069 Primary Rods: 0.039, 0.040, 0.041, 0.042 (larger is leaner) CL rod with power tip of .0667" Just to compare, for a 383/400 SBC: Primaries: .070 oe .071 CH rod with power tip of .0567" If anything start from a slightly rich condition.
JohnS

Homeport:

George Van Parys

RO# 6

Posted - Feb 16 2005 : 12:27:33
We would have the carb rebuilding kits, but we do not carry any of the metering rods or jets.
George Van Parys, http://www.boatfix.com

Homeport: Fortescue, New Jersey

jtybt15

RO# 3300

Posted - Feb 16 2005 : 12:34:45
I get the jets 'n stuff at CSK(checkers/shucks/kragen) auto stores from the edelbrock catalog. Found some of my q-jet specs. Pri: .069 jets .039 rods (I have gone up to .071 jets) Sec: H hanger/ CV rods & K hanger/ CL rods I'm presently running a spreadbore Holley.(Getting better mileage)
Charlie
Edited by - jtybt15 on Feb 16 2005 15:40:11

Homeport: Ca

tr_guy79

RO# 10887

Posted - Feb 17 2005 : 17:07:25
I ordered last night from Summit. Geesh, $10 handling charge on $33 in parts!! I went with .070/.041/CL (.0667)... I am going to stick with the current K hanger as a base line. Hopefully all of this will bring me past the 2.0 mpg mark with a little more Oomph out of the hole. W/ 2 people in the cockpit and two at the stern, it can be a challenge to get up on plane with out trimming all of the way out. If things go smooth enough, I hope the to get the Edlebrock Performer on too, I think between those two, it should make a noticable difference (carb was .069/.035/AV(.0567))
True friendship is like pee in your pants. Everyone can see it, but only you feel its true warmth.
Edited by - tr_guy79 on Feb 17 2005 17:11:38

Homeport: Elkton / Perryville MD

tr_guy79

RO# 10887

Posted - Feb 17 2005 : 17:52:26
Better mileage with the Holley? I always thought the big plus with the Q-jet is the economy due to small primaries!! George>>> Already got the rebuild stuff from you, just need the rest. I've decided on .041/.070/CL(.0667) and the "Hi-Po" accel pump from edlebrock. I figure by going with 70 jets, it will give me a 29 delta, which puts damn close to merc specs, only very slightly richer. i would rather burn a tiny bit more guess, than melt a piston or blow a h-gasket. The larger jets also give me more room to move towards the rich side if needed. I'm gonna start out with the CL rods, and maybe throw in my AV's for a run, just to see what kind of difference it makes.
True friendship is like pee in your pants. Everyone can see it, but only you feel its true warmth.

Homeport: Elkton / Perryville MD

jtybt15

RO# 3300

Posted - Feb 17 2005 : 17:59:23
Shane, The beauty of the holley SPREADBORE is it has the same primary/sec bore as the Q-jet but it has truely adjustable secondary opening ability.
Charlie

Homeport: Ca

tr_guy79

RO# 10887

Posted - Feb 17 2005 : 23:59:17
Oh, see you learn something new everyday!! Thanks Charlie. Now all I need to do is learn to post in the order the at I type and not hit enter on something I typed the night before. Everyday is a challenge to me.... -Shane
True friendship is like pee in your pants. Everyone can see it, but only you feel its true warmth.

Homeport: Elkton / Perryville MD