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Can two crusader fuel pumps fail within hours of each other? Could it be something else (not gas)

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boatingbob

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I have a 1994 Carver with twin Crusader 454XLs. Saturday I had one engine die when I brought it down to idle, and limped back to the slip on one engine. It would fire briefly, but by the time I got to the slip, it would crank but that's it. Pouring gas down the carb gets it to fire up, so I know it's not ignition. I disconnected the fuel line between the fuel pump and the carb, but do gas came out when I cranked it. The fuel filter was full of gas, and it had no water or crap in it.

I fiddled with it a bit, but have had no luck, and no indication that the fuel pump is getting power. I did learn that there's a pressure switch that keeps the fuel pump from coming on if there's no oil pressure in the crankcase. I haven't checked that (don't know how).

I decided to check out the starboard engine fuel pump, and disconnected that lead and jammed my voltmeter leads in, but go no power when I cranked that motor. After I reconnected the lead and tried to start that motor, it failed in the same way the port engine did!!! Once again, pouring a little gas down the carb gets it to fire, but that's it. I may have goobered up the contacts by forcing voltmeter leads in the socket, but who knows.

Here's one more clue: besides the 4 - 6v 'house' batteries, the boat has 3 Costco combo deep-cycle/cranking batteries which I assume are for the motors. Two of them are 10 years old, and may not be holding a charge very well. I did read on another thread that if there's a power drop across the fuel pump pressure switch circuit, it won't close and allow the fuel pump to start.

That said, if I have enough juice to turn the motor over, there should be enough to turn the fuel pump on, right?

I got tired of stabbing in the dark, so my local Crusader mechanic is scheduling a visit. If I can fix this myself, I'd be delighted, but right now, I feel like I'm stabbing in the dark. The mechanic wonders if one of my alternators isn't putting out enough power, but I don't see how that relates.

I wonder if I should try replacing the 10 yo batteries. They charge up when it's on the boat's trickle charger, but may not be holding a charge very well, as sometimes I have to switch to 'both' to get enough 'oomph' to turn the motor over.

I just can't understand how two fuel pumps can go tits up one after the other. Any thoughts?
 
Hi Mulletwagon!

This is really intriguing stuff; I'll go down to the boat tomorrow and try this trick to 'prime' the engine. It might make the difference, and explain things.

In the thread you gave the link to, one post mentioned 'prime' buttons. I have noticed on my control panel a clear soft rubber dome/button. I'm not sure it what it does. Could it be the same thing? I'll try to post a picture tomorrow.

I also do not believe two fuel pumps could fail simultaneously, but since both engines started acting up with an hours running time of each other, it implies that there is some common thread. One hypothesis I have is, since we can rule out fuel, is weather; we had some really dumping rain, and cold temps. The change in humidity and the cold could be a factor in how the engines start.

Will keep all advised; thanks for the tips!
 
Me thinks something killed them, something you need to discover or...

We engineers don't believe in coincidence, though they do happen.

Jeff
 
i think new cranking batteries ....and probably a stack of other maintenance...if batteries are 10 years old then what other loving care has been ignored...

''I did read on another thread that if there's a power drop across the fuel pump pressure switch circuit, it won't close and allow the fuel pump to start.''
 
''....another thread that if there's a power drop across the fuel pump pressure switch circuit, it won't close and allow the fuel pump to start.''
Click to expand...

The power drop is when the switch closes but the contacts are done which induces the voltage drop.....a quick check is to just bypass that switch with a jumper....10 year old batteries are likely to be on borrowed time; like it was stated, if they turn over the engine, the pumps shouldn't be lacking (from the battery anyhow). Another thing to check is the fuel pump relay.....
 
Bob,
Just another thought. Twin engines are almost completely independent. The most common culprit causing a double engine flameout is excessive water in the fuel tank (assuming both engines are feeding from the same tank). I know you said the sep was free of water but it may be worth rechecking. With all the rain some water may have gotten past the fuel cap. Please share your progress.
Have a Great Turkey Day - and don't get distracted by your nautical challenge !!
 
Thanks Mulletwagon! The mech from Gallery Marine (local Crusader spe******ts) came down today. He did some diagnostics, and wasn't familiar with the '94 454XL. He needed to go back to the shop for a schematic. He called me later and is of the mind it's either the pressure switch that keys off crankcase pressure, or switch that's off the ignition switches. Am monitoring the situation closely, as I won't pay for a 'fishing expedition'. I hired these guys 'coz they're supposed to be the best people in town working on Crusaders. Will keep all posted.

I'll also try to pull the fuel filter off the other engine in the next few, but it is clear that neither fuel pump is pumping for some reason. Why each would fail within a couple of running hours of each other is a real mystery.
 
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try running them off a different battery, that will eliminate that if they run. Like Mark said, replace the 10 year old batterys, they have live far beyond what they normaly would.
 
Bob,
Interesting problem. Do your pumps "run" but not move gas while the engine is cranking or the engine momentarily fires up ? Do you have voltage going to the pumps ? A good way to check is to open the electronics box on the right elbow and put a volt meter on the pump circuit breaker. To test the fuel pump you can put 12VDC to the CB (put the trans in gear or the starter will engage). Bad pressure switch is possible but more testing is necessary.
 
cold weather....cold oil don't flow as well...old batteries lose power..lower rpms while cranking ....i would change batteries as i said earlier...they need changing anyway...
 
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