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-   -   New 502 carb woes. (https://www.offshoreonly.com/forums/general-q/260222-new-502-carb-woes.html)

bscenvision 08-15-2011 03:51 AM

Thanks to all for replies. suggestions.. Will bring jets and demon back up next week for some test and tuning... All else fails i will get a new carb. Summers ending. just trying to enjoy the rest of it with the family. Thanks again

bscenvision 08-15-2011 03:58 AM

Just to clarihy. This motor is a New GM Gen6 502 430hp marine crate motor. Never installed in anything yet.

ezstriper 08-15-2011 05:55 AM

ok, 1st 34 deg timing to much..max 30, is the carb in the procharger box ? if so a 800 carb is what you need, but should be able to get the 850 to work..do you have a boost referenced fuel pressure regulator ? need to..what boost are you trying to run ? different carbs have a different fuel signal and may require bigger or smaller jets..I'm running a HP500 with a M3SC had carb done by prosystems..still tuning myself..

bscenvision 08-15-2011 06:20 AM


Originally Posted by ezstriper (Post 3478846)
ok, 1st 34 deg timing to much..max 30, is the carb in the procharger box ? if so a 800 carb is what you need, but should be able to get the 850 to work..do you have a boost referenced fuel pressure regulator ? need to..what boost are you trying to run ? different carbs have a different fuel signal and may require bigger or smaller jets..I'm running a HP500 with a M3SC had carb done by prosystems..still tuning myself..

Missed the first part of the post. Seller kept the pro-charger. I am going for reliable, natural aspiration. No pro-charger anymore. Thanks

ThisIsLivin 08-15-2011 07:56 AM

The cheapest thing to do would be to send the carb to Patrick at Pro Systems and have him set it up for your engine. I talked to him about doing a carb for me and it was half of a new carb.

axapowell 08-15-2011 01:22 PM

Hey Brian, change the carb to the Demon. Timing is fine at 34* and if you need jets, let me know. I'll drop off my selection you can replace what you use. I have gaskets and some power valves too!

Let me know!

Dave

bscenvision 08-16-2011 06:19 PM

Thanks to all for replys. Gonna try the demon and work off it. Called Jegs for a c.f.m recommendation. for a 502 that would turn 5k rpm and under and it figured out to be around 732cfm or so. guy told me BG demon locked the door 5 months ago. Whats out there is all thats left..,. Wow. B.G down. They've been aroung since i was a kid. Bummer....

1BIGJIM 08-16-2011 08:51 PM

I put a pair of Holley 800CFM Marine DP on the same engines.
There is another guy Balllon78 that did the exact same thing.

I took the brand new engines apart and changed the cams to RMBUILDER cams and springs. And put adjustable roller rockers on also. I jetted it up some and I spin it 5,000 at will

cplgeorge 05-31-2012 08:35 AM

Did you ever get the problem resolved, and if so what was your final solution, i bought the other motor that you didnt get, i dropped it in my Cheetah last night, but dont have anything hooked up yet, glad i read this before going through the same process. Thanks

bscenvision 06-02-2012 06:31 AM

Kinda, sorta. I put demon carb on, rejetted slightly, and set timing to 34 degrees. Run around 63 mph on gps @5200 in my 27' foot envision last year. Put about 6 hours on it. Brought it home for the winter. winterized and stored inside. Brought out 2 weeks ago to get ready for summer fun. Crankcase full of water. Working on that part now. Talked with guys who worked on both these motors at victory and there was a little story behind them unfortunetely that i wasnt told. Hope all goes well with yours.


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