Is anyone else irritated with fuel pumps?

[Hiliner222]

I have gone thru 5, yes five, electric fuel pumps in my 1998 Mercruiser 4.3 LH in the past 2 yrs since I have had this 1973 22' HiLiner cuddy. Great boat (needs tabs I think) but the fuel pumps have failed me at critical times.
Several hundred dollars has been spent pursuing this issue. I will pursue/continue this thread with those exact remedies but first, has anyone else had issues with Mercruiser/Sierra Product electric fuel pumps? I really need to solve this problem because new pumps are $220 locally.

 

[Don S]

Re: Is anyone else irritated with fuel pumps?

Used a Sierra pump last year on a boat, lasted about a month, and replaced it again, lasted 1 weekend. Replaced with OEM pump. The guy uses it all the time and it's still running.

That may not be your problem though. You can't have air or water in the system or the pump won't last. Not prefilling filters and running the pump dry hopeing it will prime will kill them quickly.
Check your fuel/water seperating fuel filter. If it's got a lot of water in it, it can and will take out any pump.

 

[Hiliner222]

Re: Is anyone else irritated with fuel pumps?

Thanks Don, I was hoping you would chime in. The first 2 pumps that went were because there was no backflow preventer on the gas tank. Fixed that and thought I was going to be OK. This newest pump is directly from Mercruiser so hoping it lasts. I always pre-fill the filter and had recently changed it out even though it did not really need it. Again, thanks for your response.

 

[JustJason]

Re: Is anyone else irritated with fuel pumps?

if the boats a 73 it's probably got a steel gas tank.
are you finding a lot of rust inside of your fuel filters?
and... and this may sound silly, but the fuel filter is in between the gas tank and fuel pump right? as in NOT in between the fuel pump and engine.

 

[Hiliner222]

Re: Is anyone else irritated with fuel pumps?

The gas tank is 4 yrs old and made of aluminum. You are correct- the filter is
between the tank and the pump. Think it is just the Sierra brand. I spoke with them (Sierra) at the Boston boat show over the winter complaining about their design and failure rate but all they did was shrug their shoulders and say we can't help you- it is common and some pumps are bad.

 

[JustJason]

Re: Is anyone else irritated with fuel pumps?

i guess you can try hooking up your ammeter in series with your fuel pump and see what it's drawing for current.

 

[hard-3]

Re: Is anyone else irritated with fuel pumps?

check the voltage at the pump with a good digital voltmeter. Low voltage will trash an electric pump real quick. the ammeter will also show it. electric fuel pump motors are cooled by the fuel running through the pump. If the fuel is hot , it will cause the pump to overheat, making the windings in the motor have more resistance. Any additional resistance in the fuel pump electrical supply can cause the voltage to drop. check all connections at relays,fuse blocks , circuit breakers and pressure switches

 

[Hiliner222]

Re: Is anyone else irritated with fuel pumps?

never thought of voltage drop- that may be it, time will tell. I replaced the pump and the engine would not turn over- old battery. Replaced it and everything is fine. Maybe the low voltage produced by the battery was the cause. Thank you very much to all that replied-each was helpful. Thsi problem has/had me stumped. Now I hope that Mercruiser honors the year warranty on the old one.