fuel pump prime

« **on:** October 06, 2012, 09:43:21 PM »

Mrkv bbc stock.. when you start the boat cold; the second you start cranking shouldnt the fuel pump turn on or at least prime with key on? When i start my boat it will crank 5 to 6 times no start. No pump noise. Once i crank over again if it doesnt start after 5 cranks ... then the fuel pump primes. Then it fires right up. I have a rochester carb and it leaks fuel internally so it takes a while to fill the bowl back up. Is this normal?

« **Reply #1 on:** October 06, 2012, 10:03:48 PM »

im a rookie but its not normal first internal leak is bad cuz if u leak and dump to much fuel u can vapor lock the moto no bueno so rebuild and fix this now as fuel pump how is it wired does it have its own switch is it ran to to run termanal on key?

?? more info is needed or are u just jumpin in turning the key and not letting it prime help us out

« **Reply #2 on:** October 06, 2012, 10:43:33 PM »

im not sure how the pump is wired, but im guessing its wired in with this junk ... pics below. i jump in the boat, turn the key on and the pump will not prime at all. after a couple cranks it will make a loud buzzing sound which is the fuel pump and boom it fires up. once it fires up it runs like it should. when the boat sits over night , every time i go to start it, the first 6 cranks it will not start. yes i know its old school big block and cold start is a bit rough at times but once that fuel pump runs it will fire right up. but you would think the pump would prime and turn on once the key is on, and it doesnt.

« **Reply #3 on:** October 06, 2012, 10:56:01 PM »

so it doesnt have an exterior switch to start the fuel pump, did the fuel pump ever turn on when you would turn your key to the run position? If it used to turn on when you turned it to the run position and it doesn't now your fuel pump is probably going out or your ingintion switch is going out. Its hard to say because your pictures dont show where the fuel pump is getting its power from. You need to chase the hot wire on your fuel pump and find out where it goes. Make sure its hooked up properly, power and ground. If it is, again its your pump. Idk, its hard to tell until you do more homework.

« **Reply #4 on:** October 08, 2012, 02:16:21 AM »

Quote from: 80mphpls on October 06, 2012, 10:56:01 PM

so it doesnt have an exterior switch to start the fuel pump, did the fuel pump ever turn on when you would turn your key to the run position? If it used to turn on when you turned it to the run position and it doesn't now your fuel pump is probably going out or your ingintion switch is going out. Its hard to say because your pictures dont show where the fuel pump is getting its power from. You need to chase the hot wire on your fuel pump and find out where it goes. Make sure its hooked up properly, power and ground. If it is, again its your pump. Idk, its hard to tell until you do more homework.

The ignition switch is the first thing I would try. Those things are cheap, not only to buy, but cheaply made, and notorious for all sorts of similar and not so similar issues. One of the first things I replaced on all my boats when I got them whether needed or not. The one on Moo was new when I got it and stranded me at Bartlett Lake on her second trip.

Ray

« **Reply #5 on:** October 08, 2012, 06:34:43 AM »

I would guess that the fuel pump is powered through an oil pressure safety switch. Meaning that you have to have oil pressure before the fuel pump gets power. If that is the case you need to look into installing a momentary switch for priming.

« **Reply #6 on:** October 08, 2012, 07:23:48 AM »

Hey crewchief you are right, by the pic
I see its a marine power with a carter pump
And it does need oil pressure before the
Pump kicks on, if the carb is leaking it needs
To be rebuilt, usually the pump should start running
After a few revolutions of cranking.
I had lots of problems with mine "same set up"
I by-passed the oil pressure switch and ran
a holley red marine pump and problem solved.

« **Reply #7 on:** October 08, 2012, 08:29:11 AM »

I wired my pump that way too, off of the oil pressure. I jump the switch for a little if the boat sits for a while. I used a 2$ push button and ground it to the switch. Key on push it till it sounds like the Carb is full and then crank. I was worried that one day it would back fire and u know fire and gas all over.

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« **Reply #8 on:** October 08, 2012, 11:05:54 AM »

Quote from: crewchief22 on October 08, 2012, 06:34:43 AM

I would guess that the fuel pump is powered through an oil pressure safety switch. Meaning that you have to have oil pressure before the fuel pump gets power. If that is the case you need to look into installing a momentary switch for priming.

thats whyu i love this place u learn something every day

« **Reply #9 on:** October 08, 2012, 12:37:08 PM »

Quote from: crewchief22 on October 08, 2012, 06:34:43 AM

I would guess that the fuel pump is powered through an oil pressure safety switch. Meaning that you have to have oil pressure before the fuel pump gets power. If that is the case you need to look into installing a momentary switch for priming.

Bingo.

I keep a jumper wire with alligator clips so I can run my fuel pump off my battery if the oil switch stops working. The switch has failed before.

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« **Reply #10 on:** October 08, 2012, 12:39:14 PM »

Quote from: 80mphpls on October 08, 2012, 11:05:54 AM

thats whyu i love this place u learn something every day

The oil pres switch is above the oil pan and below the exhaust manifold on the left side of your motor toward the rear.

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« **Reply #11 on:** October 08, 2012, 07:16:40 PM »

Damn you guys are good

its def. Wired to the oil pressure switch. Makes total sense now. Thank you guys.. looks like i need a new ignition switch or tumbler and some jumper wires just in case it goes bad. Sounds like its normal so i will deal with the long cranks at cold starts. Thanks again

« **Reply #12 on:** January 23, 2013, 08:44:59 PM »

Nice to see I'm not the only one with that problem. Same set up (for the most part) all stock marine power sport pack, same problem. But I have an additional issue. I'll try and explain this as best as I can. After fueling the boat runs great! Issue is once the boat sits after a short period of time (5 min or so) fire it back up, let it idle, get on gas and it acts like it wants to stall, I pump the pedal a few times if I'm lucky the boat will run, and run great like I said.
Ive explained this to a mechanic, and he seems to think that that my fuel lines could be getting clogged. I do not have a inline fuel filter, and for whatever reason it happens to one tank more than the other.
Priming issue, fuel pump issue, carb issue? Any advice would be greatly appreciated.

« **Reply #13 on:** January 24, 2013, 06:47:12 PM »

Quote from: sevans01 on January 23, 2013, 08:44:59 PM

Nice to see I'm not the only one with that problem. Same set up (for the most part) all stock marine power sport pack, same problem. But I have an additional issue. I'll try and explain this as best as I can. After fueling the boat runs great! Issue is once the boat sits after a short period of time (5 min or so) fire it back up, let it idle, get on gas and it acts like it wants to stall, I pump the pedal a few times if I'm lucky the boat will run, and run great like I said.
Ive explained this to a mechanic, and he seems to think that that my fuel lines could be getting clogged. I do not have a inline fuel filter, and for whatever reason it happens to one tank more than the other.
Priming issue, fuel pump issue, carb issue? Any advice would be greatly appreciated.

About how much fuel is remaining in the tanks when the problem starts? If it runs great after fueling but starts having a problem after running the tank/tanks down, maybe it is sucking air at the fuel pick-up tube.

Good luck

« **Reply #14 on:** January 25, 2013, 07:03:24 PM »

After fill up and first run of the day the boat runs fine. As soon as I shut down that's when the problem starts, and progressively get worse as the tanks draw down. Left tank will fire and idle no problem ease my way into throttle and die cannot start the boat on left tank. Switch to right tank, once fuel gets to the carb boat will fire it'll run and I can switch to the left tank boat will run, as long as I don't shut down

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