Changing fuel system on twin 496ho
02-20-2018, 07:24 AM
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Changing fuel system on twin 496ho
Ok here's what I would like to do loose the low and heigh presure merc pumps and replace with a top quality high presure pump bolted low in the boat but where I can easily get at it .
Next replace the regulater with a top quality ajustable reg and have it up on the fuel rail where I can get at it .
loose the coolfuel system and return fuel to the tank .
Will this work ok .
my reasons for whanting to do this is one its extremely hard to get at all the merc stuff on twins in a 28 ft boat plus boat sits for long periods and pumps seem to seiz up and need a few bangs to get them ticking again on my second set of pumps and I know there's better out there .
last of all there's a what looks like a second fuel Reg on the fuel rail but iam sure I was told by Bupe on here it's just a dappner even throw in my merc workshop manule there calling it a reg? Thank for any help and advice Paul
Next replace the regulater with a top quality ajustable reg and have it up on the fuel rail where I can get at it .
loose the coolfuel system and return fuel to the tank .
Will this work ok .
my reasons for whanting to do this is one its extremely hard to get at all the merc stuff on twins in a 28 ft boat plus boat sits for long periods and pumps seem to seiz up and need a few bangs to get them ticking again on my second set of pumps and I know there's better out there .
last of all there's a what looks like a second fuel Reg on the fuel rail but iam sure I was told by Bupe on here it's just a dappner even throw in my merc workshop manule there calling it a reg? Thank for any help and advice Paul
02-20-2018, 09:51 AM
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In the fuel line above the intake -- its a dampner and it is needed especially with stock tune. And depending on your year - I have alot to say and many will be shocked as very few even know this about the fuel line itself and cool fuel set up depending which year and which stock set you have for the OEM Merc 496.
02-20-2018, 10:07 AM
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just in case if anyone doubts what I am saying, EF Hutton
http://ww2.justanswer.com/uploads/ke...5804_EN_09.pdf
http://ww2.justanswer.com/uploads/ke...5804_EN_09.pdf
02-20-2018, 10:07 AM
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In the fuel line above the intake -- its a dampner and it is needed especially with stock tune. And depending on your year - I have alot to say and many will be shocked as very few even know this about the fuel line itself and cool fuel set up depending which year and which stock set you have for the OEM Merc 496.
02-20-2018, 10:12 AM
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just in case if anyone doubts what I am saying, EF Hutton
http://ww2.justanswer.com/uploads/ke...5804_EN_09.pdf
http://ww2.justanswer.com/uploads/ke...5804_EN_09.pdf
02-21-2018, 01:26 PM
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Ok here's what I would like to do loose the low and heigh presure merc pumps and replace with a top quality high presure pump bolted low in the boat but where I can easily get at it .
Next replace the regulater with a top quality ajustable reg and have it up on the fuel rail where I can get at it .
loose the coolfuel system and return fuel to the tank .
Will this work ok .
my reasons for whanting to do this is one its extremely hard to get at all the merc stuff on twins in a 28 ft boat plus boat sits for long periods and pumps seem to seiz up and need a few bangs to get them ticking again on my second set of pumps and I know there's better out there .
last of all there's a what looks like a second fuel Reg on the fuel rail but iam sure I was told by Bupe on here it's just a dappner even throw in my merc workshop manule there calling it a reg? Thank for any help and advice Paul
Next replace the regulater with a top quality ajustable reg and have it up on the fuel rail where I can get at it .
loose the coolfuel system and return fuel to the tank .
Will this work ok .
my reasons for whanting to do this is one its extremely hard to get at all the merc stuff on twins in a 28 ft boat plus boat sits for long periods and pumps seem to seiz up and need a few bangs to get them ticking again on my second set of pumps and I know there's better out there .
last of all there's a what looks like a second fuel Reg on the fuel rail but iam sure I was told by Bupe on here it's just a dappner even throw in my merc workshop manule there calling it a reg? Thank for any help and advice Paul
02-21-2018, 01:56 PM
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No expert on a 496 (That be BUP) but my opinion.
The current fuel pressure regulator is mounted on the cool fuel module (item 15). The damper/regulator (IMO is a secondary regulator) on the fuel rail which helps smooth the fuel pump pulses
Genuine Mercury & Mercruiser parts. Cool Fuel System
All of Merc's cool fuel systems work but are not designed very well. They all need to have the excess pressure go back to the tank, sending it back to the filter is dumb. Replacing the 2 pumps with one should not be an issue, folks here do it to their motors all the time. Installing a regulator up top should not be an issue, and might keep pressure a tad smoother.
My 502 came with to regulators, one on the fuel module and one on the fuel rail. The Reg one on the rail is adjustable. When the motor was rebuilt, the return line from the fuel rail goes back to the tank after the upper regulator. So right now the lower regulator is there but has no way of returning fuel back to the filter or anywhere else. the one on the fuel rail keeps pressure at 40 psi, and all is good
The current fuel pressure regulator is mounted on the cool fuel module (item 15). The damper/regulator (IMO is a secondary regulator) on the fuel rail which helps smooth the fuel pump pulses
Genuine Mercury & Mercruiser parts. Cool Fuel System
All of Merc's cool fuel systems work but are not designed very well. They all need to have the excess pressure go back to the tank, sending it back to the filter is dumb. Replacing the 2 pumps with one should not be an issue, folks here do it to their motors all the time. Installing a regulator up top should not be an issue, and might keep pressure a tad smoother.
My 502 came with to regulators, one on the fuel module and one on the fuel rail. The Reg one on the rail is adjustable. When the motor was rebuilt, the return line from the fuel rail goes back to the tank after the upper regulator. So right now the lower regulator is there but has no way of returning fuel back to the filter or anywhere else. the one on the fuel rail keeps pressure at 40 psi, and all is good
