SoCal Jet Boats
Discussion => The No Wake Zone => Topic started by: badcapri2004 on July 15, 2008, 10:49:27 PM
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ive had a couple of elec fuel pumps on my tahitti, each one ive tried feels hot after 10 minutes idling in my driveway. ive got the duel tanks. its pumping fine,im just concerned because it feels awfull hot.
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Is the fuel pump an inline or a coupled pump, the inlines are cooled by fuel flow, the coupled pumps are cooled by air and tend to run hotter to the touch, how hot is hot?
The first thing to check is make sure you have a really good ground, seems to be the weak link on running an electric pump in a boat, I actually mounted my Holley blue pump to the engine mounts to ensure a good connection to ground (-), also in an effort to reduce the voltage drop I have a small relay running the pump at the back of the boat near the battery. Otherwise the power for the pump goes from the battery to the dash and back again, that's like 30' of wire in my boat, not to mention the fuse, switch, and the other connections..
Thats my .02c
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BTW, quik electricity lesson here.
As voltage drops, amperage goes up and vise-versa.
If you have signifigant voltage drop (1-2 volts) you would have a 10-20% increase in amperage (approximate), amperage is what generates heat, if a motorized electrical component draws too many amps it will overheat and eventually fail. The easiest way to fight voltage drop is to make as few connections and as short of wire length as possible, and make sure the charging system is up to the task.
Some (not all) boats use a single wire alternator (Delco) and these tend to "undercharge" when the engine is idleing, especially when using a larger pulley to prevent overspinnig the alt. (not needed under 6000 rpm or so) they basically generate their own "exciter" circuit, which is weakest at idle.
Sorry for the verbal diarreah, but seemed related.
OOOH! almost forgot, Welcome to this disfunctional but very fun place >:D
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thanks great stuff! its an inline,got it mounted down on the engine stringer,gorund wire to the eng block,pretty short wire! my ingnition switch also gets warm, i had my ground wire from the dash to the motor short before and melt. i replace it,but i dont think i used a heavey enough gauge, actually it was like to speaker wires wrapped together(lol). id better go with a bigger gauge than that hah! thanks guys!
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If your switch is getting warm, it is pulling too many AMPS through it lowering the voltage (the switch and wires are acting like a big resistor) which in turn is making your pump have issues.
A fire waiting to happen in my opinion.
Go buy a relay, and wire it in so the current + wire turns on the relay instead, and the pump gets its power from the battery through the relay.
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If your switch is getting warm, it is pulling too many AMPS through it lowering the voltage (the switch and wires are acting like a big resistor) which in turn is making your pump have issues.
A fire waiting to happen in my opinion.
Go buy a relay, and wire it in so the current + wire turns on the relay instead, and the pump gets its power from the battery through the relay.
X2
I used a relay designed for driving lights, (Hella) its cool, looks like a black cube.
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Hey badcapri!, does your boat have an ammeter or a voltmeter?
If its an ammeter, I would ditch it for a voltmeter, mucho' betta!
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ita an ammeter,ill do that. im also going to install a relay! thanks guys for all the great info,shure helped me a bunch !!!!!!!!!!!! ive got to relay all this great info to my neighber whos got the same set up!