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#1
04-19-2014, 10:24 PM
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fuel tanks
Okay here's the scoop .. I have two 75 gallon tanks with 3/8" pickups... I am going to run twin150 s on my 23.. My question is can I run both engine on one tank at a time and if so how do I valve them... I have two fuel separators for each engine. I need your input guys.. Thanks Martin
PS there is only one pickup in each tank 
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#2
04-19-2014, 10:52 PM
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I have two pick ups on each tank and two fuel filters. So one line comes from each tank to rack fuel filter. This is my setup. I'm not sure how the best way to set it up with one pickup per tank?
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#3
04-19-2014, 11:16 PM
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Two pickup from each tank would ideal. But i only have one... I see you have two valves and anothernipple on the top what is that for.. Are you running twins ? Are there two picup tubes or just one with a y manafild
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#5
04-20-2014, 12:52 AM
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Quote:
heres a digram of it{sorry for the crude artwork)
__________________
1973 20' seafari ob "old Yeller" sold 1972 25' seafari W/ 150 mercs {under renovation}
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#6
04-20-2014, 09:19 AM
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This is the way my set up works...single engine two tanks... you can get the general idea and just adapt for twins.
__________________
[SIGPIC][/SIGPIC] "If You Done It...It Ain't Braggin" my rebuild thread: http://www.classicseacraft.com/commu...ad.php?t=18594
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#9
04-20-2014, 03:56 PM
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Do I understand your proposed filter setup correctly - 2 filters in series between the tank and EACH engine? Seems that is just adding additional restriction on a setup that may already be marginal, trying to suck enough fuel for 300+HP through a single 3/8" line and 4 filters. You're probably OK because they're older carb'd engines that run a fair amount richer than the newer low emission DI 2-strokes and EFI 4-strokes. All the "clean tech" motors are lean enough that there is very little margin for any fuel starvation! Leaning out a cylinder dramatically increases combustion and piston temperatures, leading to scuffed pistons and scored cylinders if not outright piston failure. E-10 gas burns even hotter because of the extra oxygen content of the ethanol, so I'd definitely try to avoid running E-10. Your engine setup is particularly vulnerable to excessively lean operation because you'll have enough power on that rig that you might not notice a slight reduction in output due to a leaned-out engine until it's too late!
You can do several things to minimize fuel restriction and risk with this setup: 1. Use only one Racor type filter per engine. (An additional on-engine filter is OK as long as it's downstream of engine lift pump. You could run a 10 micron filter here and a 30 micron Racor to minimize restriction on suction side of pump.) 2. Carefully check all fittings to make sure the internal passages are drilled out to 3/8". Years ago I heard of a boat that failed a couple of powerheads because one of the 3/8" elbows in fuel system was only drilled out to 1/8" internally! 3. Minimize use of 90* elbows; use 45* fittings or straight fittings and extra hose instead to avoid tight radius turns in the fuel flow path. 4. Tee in a temporary vacuum gauge between last filter and engine, and check vacuum reading at WOT. Also use some clear hose on the fuel side of the "T" to check for air leaks. Don't know how much restriction Merc allows in boat's fuel supply, but BRP specifies a Max Allowable pressure loss of 4"Hg for the E-TEC's, so you should be OK if you don't exceed 4" on a carb'd motor.
__________________
'72 SeaFari/150E-Tec/Hermco Bracket, owned since 1975. http://i188.photobucket.com/albums/z...Part2019-1.jpg
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#10
04-20-2014, 08:03 PM
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Quote:
__________________
1973 20' seafari ob "old Yeller" sold 1972 25' seafari W/ 150 mercs {under renovation}
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Linear Mode
