Need to install an electric prime pump

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Boater On Thames

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Like I mentioned in another thread. The port side engine suddenly stopped and can't restart while I drive my boat on the way home this morning. It looks like the fuel pipe has air in and can't prime anymore even with a small electric fuel pump and hand prim pump working together.

The port engine is now back to normal after prime it a few more times after mooring. Obviously, the small electric pump I installed last year is useless, it can't prime by itself, so still need a hand pump. I think I need to replace it with a bigger electric pump to make it can prime by itself solely. So if this situation happens again I will be able to restart the engine easier right away.

What electric pump will you suggest for this prime job? Thanks.
 
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I have tracked the fuel hose from the engine to the fuel tank. I can't see leaking or a crack, and all clamps are so tight. I can't found why yet. But it may happen again sooner or later. In case that happens while I am on the water, so add one bigger electric prime pump seems not a bad idea.
 
Question is, is the system sucking in air when running, or are you losing the fuel pressure by air slowly seeping in when at rest? I would have thought that any air getting in after the pump when the engine is not running, would be leaking fuel when running, so easy to spot. If the engine runs for a while before cutting out, especially if it's not been run for a while would point to a leak in the pipework somewhere between the tank pick-up and the lift pump (I'm getting a feeling of deja vu - I think we've done this topic before :-) )
 
Haven't start it for more than two months while she was on the hardstanding. Tried to start two days ago but failed, prime and started eventually. today starting ok, I let the engine run for about 10 minutes before I leave the marina. Driving for around 15 minutes, the engine was off suddenly.

No leaking was found after a double-check today. I see the air bubbles come up in the primary filter when priming. I will keep running the engine tomorrow to see if it will be off or not.
 
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check the fuel pre filter lid is tight etc…

if it cuts out again….see how much fuel is left in the prefilter or if it sucked it empty
 
The spin on .When you changed it did you check if you removed the little 0 ring in the centre where it screws ?Often this is hidden out of sight under the hood / spin on bracket .
Some OEM have them , some after market do not .Anyhow it’s possible to get into a muddle and effectively double O ring it .
Still nips up tight ish .Because they are mounted high leaks out ( Marc s point ) are hard to spot .But sooner or later running the Vac sucks air in.It’s near the pump = stutter and stop .
 
Lucas Gan said:
No leaking was found after a double-check today. I see the air bubbles come up in the primary filter when priming. I will keep running the engine tomorrow to see if it will be off or not.
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I think this statement certainly narrows down where the problem is, you're sucking in air. No need for priming pump, just find the leak. Porto's suggestion in a great place to start. Next would be all pipe joints from the tank to pre filter. Last option is pick up in tank, maybe you can switch feed from the other tank to check?
 
I am now actually using the port side tank to feed two engines. The starboard engine has no problems keep running even when the port engine was stopped yesterday. So the only possible air gets in is between the distribution valve to the port pre-filter as I saw air bubbles. There is only one hose from the valve to the pre-filter. Not found leaking or crack over there yet. Or maybe like Mr Googler said the filter lid. Will check again both. The port engine now starting normal, so need to keep monitoring for a few days to see.
 
The air gets in the fuel hose continuing. The air bubbles are seen inside the pre-filter at the orange circle point show in the attached picture when priming. I already refitted the pre-filter inlet hose and the outlet hose from the distribution valve as well. Still no better. The port engine will stop after around 15-20 minutes. Prime it then will see again air coming up from the orange circle point insiders pre-filter. The two engines are feed by the same tank. The starboard engine never had this problem. So that means thank pickup hose no problems. Is it possible just the problem is the distribution valve? Because no others I can think of already, see the system diagram. Look like the only way to find out is to replace the distribution valve. Any advice? Thanks

Sorry for my terrible handwaving on the system diagram on my phone.
 

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I already checked the o ring and it looks good and tight. The fuel inside the filter is quite full. And the bubbles clearly come out from the orange point which is the input point inside the filter. So looks like the lid is ok, and this is not caused by the lid I think.

Is the lid leaking air, or the part after pre-filter leaking will cause bubbles to come out from the pre-filter input point? I don't know. Any idea?
 
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I have to mention there is no fuel leak found in the whole fuel system. All hoses, connectors, and valves are dry. So it is a bit confusing how the air gets in.
 
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The screw in fittings into the racor filter on the input side of the unit may have been removed and refitted without thread seal/lock. Could be worth taking them off cleaning it all and re-sealing. Rubber hose between filter and valve and tank is porous? replace it all with new. Possibly replace the fuel valve too. You may not find which piece has failed but you should be able to stop the air leak.
 
Lucas Gan said:
@markc I am using one tank feed two engines, only one engine has this air in problem.
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Yes I totally get that - which means the air is being sucked in in an easily identifiable number of places. Good suggestion by kashurst. I would also replace the Racor filter, making sure to remove the lid gasket, clean mating surfaces and put in a new one, the same with the o-ring for the t-handle. On my Racors I have vacuum pressure gauges and if I hand prime, the gauges get a really high reading - i.e., there's a lot of sucking going on!
 
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