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Fuel lines/fittings 496

02HoWaRd26

DCBroke
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The 496ho in my boat seems to run real well however was talking to a reputable shop about upgrades (headers & tuning) and they suggested first and foremost to look at the existing fuel lines from tanks to IMCO fuel valve then from valve to the pump. He said to be sure I had 1/2" id not 3/8" id as I guess it's a common mistake on these 496 motors and he stated that making sure the fuel volume never has that little extra opportunity to drop via lack of supply was very important. Well my boat has all 3/8" lines so I'm getting ready to buy all the hardware and hose, but it has me thinking to go to AN fittings rather then the barbs and hose clamps, yea will cost a little more but will be prettier as well I feel safer down the line. Did some looking around and don't seem to be able to find pictures of any smaller Merc fi motors (377 scorpion, 496's, 8.2's or even 525's) running an fitting suit all seem to run barbs and hose clamps. Is there a reason for this or is it the fact most just do not care to spend the extra cash on such a minut thing
 

AzGeo

Fair winds and following seas George.. Rest Easy..
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If it is working now, why would you change anything ?

Look, a 3/8" line will have better "draw" than the same length line in 1/2" . It's all about "vacuum force across an open volume (hose diameter) .

Which model year 496 do you have ? The one with two fuel pumps or the one with a large integrated fuel management box ?

Sucking fuel and pushing fuel are two totally different issues . Fuels pumps have measured values for sucking and pushing, and that includes mechanical and electric pumps .

IF YOU HAVE A FUEL STARVATION PROBLEM, you should look for the "smallest fuel passage", in all your fuel lines/fittings, since most all brand named normal use gas marine engines are designed to run well on 3/8" lines .

If your fuel tank or tanks have "check valves", I would start there, to inspect them for "clogging" . Next I would look at "tank air vents", which could restrict the flow of fuel out of the tanks .

If you are not having any fuel flow related problems, why look for them ?

You know that your fuel tanks have 3/8" pickups and fittings, so do they also want to change them too ? (total BS until you get to 1000 Hp or more)

If you are looking at doubling the power, then maybe you need a change, but headers and ECM tune up don't require all that BS .
 

02HoWaRd26

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If it is working now, why would you change anything ?

Look, a 3/8" line will have better "draw" than the same length line in 1/2" . It's all about "vacuum force across an open volume (hose diameter) .

Which model year 496 do you have ? The one with two fuel pumps or the one with a large integrated fuel management box ?

Sucking fuel and pushing fuel are two totally different issues . Fuels pumps have measured values for sucking and pushing, and that includes mechanical and electric pumps .

IF YOU HAVE A FUEL STARVATION PROBLEM, you should look for the "smallest fuel passage", in all your fuel lines/fittings, since most all brand named normal use gas marine engines are designed to run well on 3/8" lines .

If your fuel tank or tanks have "check valves", I would start there, to inspect them for "clogging" . Next I would look at "tank air vents", which could restrict the flow of fuel out of the tanks .

If you are not having any fuel flow related problems, why look for them ?

You know that your fuel tanks have 3/8" pickups and fittings, so do they also want to change them too ? (total BS until you get to 1000 Hp or more)

If you are looking at doubling the power, then maybe you need a change, but headers and ECM tune up don't require all that BS .


No I am not having any known issues whatsoever, but when talking to BoostPower they said it's a critical issue for the 496 that they need the 1/2" fuel hose to help prevent starvation. The motor has nearly 200hours and has obviously been ok but when someone tells me that this can or is an issue I automatically head to change and repair. And yes would have to change the fittings in the tank at the valve and at the pump to do the 1/2" lines vs the existing 3/8" lines. That's what got me thinking to go to all an fittings as then I'd change all the fittings then build my lines and be done.
 
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