454 marine 17080560 questions

[Okie BB]

Cliff, Upon disassembly of this stock 17080560 the set-up is:
Primary jets=.070, rods=#42, tip .026, Float level 6/32" (nitrile), Secondary rods = CL, hanger "G".
Application is: basically stock 454 - 340 hp, 800' altitude, 75-105* ambient temps, 140-160* coolant temps, 35* total timing, Edelbrock performer intake, thru transom exhaust.
Merc set these engines up for 50-state & Worldwide distribution
1) If you agree, I think the primary side looks pretty good.
2) Thought to lower the float level down to 11/32".
3) Some marine 427's & 454's used AJ secondary rods. Do you think the CL's are to lean? I'll crack into the secondarys for max torque to get up on plane, then cruise @3000 rpm. Would a AY rod be a good choice?

Your thoughts and suggestions are Greatly appreciated.

Thank You

[Cliff Ruggles]

I wouldn't lower the float level, as doing so effects fuel delivery every place.  That calibration should be close.  We sell complete kits for the Marine carburetors, with upgraded components for modern fuels containing ethanol and other additives that do NOT like rubber parts......Cliff

[Okie BB]

Thanks Cliff, I'll get with you on a kit. Just seeing if any other changes were in your thinking. OK on ethanol as marine fuel sold "on-water" doesn't have any. I guess thats the only good thing about paying 4.75 per gallon on the water.
It sounds like you're good with all of the factory set-up, on thing I did not address and makes me wonder in these always loaded engines is the secondary wind-up. Settings on these marine engines range from 1/4 turn to 3/4 turn. Does it really make much difference? The pull-off will already be fully extended as manifold vacuum will be long gone I would think.

Thanks Again.

[Cliff Ruggles]

Our kit sales of Marine carburetors has increased significantly in the past two years.  Currently available fuel is killing rubber parts, most of it now has ethanol in it.  Nothing at all to be afraid of, as ethanol has a few good qualities, it just hates rubber and absorbs water, so leaving it alone for long periods of time is pretty hard on any vented fuel system.

I wouldn't make any changes to the carb, unless something with the engine has been changed that would effect vacuum at idle speed.

The best approach in all cases, is to completely and correctly rebuild the carb with good parts.  Test it, and go back and make any changes if/as needed.  In most cases with Marine carburetors, the will not need recalibrated unless a cam was chosen that lowers vacuum at idle.  They do not use idle bypass air, and are no emission calbrated, so they is always plenty of idle fuel available.  Where folks get into trouble with Marine set-ups, is poor camshaft selection, when vacuum is lowered at idle and low speeds.  Marine engines spend a lot of time there, or at least enough time that they need to idle well and be efficient when docking, entering and leaving Marina's, etc.....Cliff