Electric fuel pump.

pvb said:
For some reason, Beta engines seem to have a feeble lift pump. Beta say a suction lift of 0.25m is about the limit. I had a keel tank in my last boat, and Volvo Penta engine happily sucked the fuel up from about 1.0m down.
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I agree, the lift pump is poor, but I expect it is to do with the engines antecedents as a plant engine with a tank right next to the engine. Anyway, the electric pumps work well.
 
Graham_Wright said:
That was my experience until the piston pump became clogged. Encouraging to hear the diaphragm pump was a success.?
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The small inline see through filters before the pump ensured cleanish fuel reached the pump but the filters can clog, so a quick visual is needed from time to time.
 
WoodyP said:
The small inline see through filters before the pump ensured cleanish fuel reached the pump but the filters can clog, so a quick visual is needed from time to time.
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Those tiny inline filters would be pretty well useless in the event of any serious crud getting stirred up in the tank in rough seas. Even a proper primary filter can soon get clogged. Messing about with cheap electric pumps and tiny filters is a problem waiting to happen, as I said in post 10. The real solution is to tackle the air leak.
 
pvb said:
Those tiny inline filters would be pretty well useless in the event of any serious crud getting stirred up in the tank in rough seas. Even a proper primary filter can soon get clogged. Messing about with cheap electric pumps and tiny filters is a problem waiting to happen, as I said in post 10. The real solution is to tackle the air leak.
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I know, that's why I spent hours getting covered in diesel pumping out the tanks, cleaning them and filtering the fuel. Horrible job.
 
Bit of feed back. The pump failed to self prime when dry. With a little diesel down the inlet it pumped bu failed to lift 300mm. Lowered into the tank, it produced a very vigorous flow. Connected to the fuel system, it detected quite a few leaks. Once these were tightened up, the air detector filled and was bled. The engine is not currently runable (ashore) but the concerns, which I shared, related to the Chinaspacher heaters. They both seemed to work as before but the dosing pumps would not pull through the in-tank pump (as expected). There was no smoke from either and the in-tank pump did not pulse if the dosing pumps were off. Further tests needed but encouraging. I need to determine if the pump is liquid tight. If so, I will probably run it submerged in the tank.
 
A couple of thoughts spring to mind reading this, from my own experience.
  1. Get rid of any gauze on the end of the stand-pipes / pick-up pipes. In my experience these cause problems sooner or later, and a proper pre-filter(s) will do the job
  2. As mentioned, if you have enough debris in your tank to block something - remove it. You can get a fuel polisher for not much money, or rig something up. But trying to "manage" the problem without treating it will eventually come back to bite
  3. Also as mentioned, if you have air leaks - find & fix them. It sounds like you have done most of this so great job, but keep an eye on it (as you acknowledge it has been a persistent problem)
  4. Make sure the electric pump is not providing too much pressure. I have seen problem, especially on smaller consumers like diesel heaters where the internal regulating valves have struggled due to be over-pressured. A vane type pump is not ideal in this application due to this reason
  5. If you are only using the pump for priming/bleeding, consider installing it on a parallel line with some inline valves. That way it is only operated when needed and doesn't have to be run all the time. If pickup is an issue, a pump will be needed - in this case I suggest installing two in parallel so that you have redundancy should one fail on you.
 
Moodysailor said:
A couple of thoughts spring to mind reading this, from my own experience.
  1. Get rid of any gauze on the end of the stand-pipes / pick-up pipes. In my experience these cause problems sooner or later, and a proper pre-filter(s) will do the job. Please define pre filter.
  2. As mentioned, if you have enough debris in your tank to block something - remove it. You can get a fuel polisher for not much money, or rig something up. But trying to "manage" the problem without treating it will eventually come back to bite My tanks have excellent access thus easy to clean
  3. Also as mentioned, if you have air leaks - find & fix them. It sounds like you have done most of this so great job, but keep an eye on it (as you acknowledge it has been a persistent problem). One benefit of the pump is for finding leaks but it will not find this due to suction
  4. Make sure the electric pump is not providing too much pressure. I have seen problem, especially on smaller consumers like diesel heaters where the internal regulating valves have struggled due to be over-pressured. A vane type pump is not ideal in this application due to this reason. There is no regulating valve on my heaters. They are fed from dosing pumps.
  5. If you are only using the pump for priming/bleeding, consider installing it on a parallel line with some inline valves. That way it is only operated when needed and doesn't have to be run all the time. If pickup is an issue, a pump will be needed - in this case I suggest installing two in parallel so that you have redundancy should one fail on you. The engine lift pump could suck through the previous pump. I have not tried with the new one. I have two tanks each with their own pump and each with their own filter. Our departure from Lydney harbour would have been much less" exciting" if I had kept the pump running. The pump is designed to run continuously - it is the same as fitted to my MG.
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Pre-filter = 10 micron fuel filter with replaceable element located in the fuel line between the tank and any consumer (engine/heater, etc). Usually, a priming pump is positioned before this filter, but if you are having issues with blockage in the pump, and if the pump is used for supply then this can be placed after the filter. Separ and Racor are highly recommended, there are other types also. I added the (s) as you may want to have one filter for each consumer, however this is your choice 9

Tank access - if this is good, then can you elaborate on what is blocking the pump?

Air leaks - I advise to treat this as a separate issue. Place the pump in the position where it will do it's primary job best. Then tackle the air leaks. If you have a fuel shutoff valve at the tank you can isolate this, then disconnect the fuel intake at the engine and pressurize the line (only needs to be to 5-8psi) using a hand pump. This will test the entire fuel supply line from the engine to the tank without disturbing any fittings. Once you have found and rectified any leaks there, if you still have air getting in it is a small process of elimination to determine if it is from the fuel return or from the standpipe.

Pump type - the original pump you linked is a piston type, the latter one is a diaphragm type. I would advise to be very careful with the diaphragm type - definitely test with this before trusting it fully. Generally, the "facet" style plunger pumps are more common on diesel installations, although this one may work just fine. I echo my earlier words - as it's designed for the automotive market, definitely carry a spare.
 
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Every joint above the free surface level in the diesel tank will be at sub-atmospheric pressure when the engine is running or stationary. Sorry to state the obvious.
Less obvious is that the pulsating nature of the pump will mean that even some joints or components below the diesel level may be sub-atmospheric for part of each pump cycle. But once air gets in, there is no way out. So check joints and seals with a partial vacuum in mind. Good luck.
 
ianj99 said:
Just a thought.
Is there a return pipe from the engine filter to the fuel tank?
if so, is there an upward anti syphon loop in it?
My old Perkins 4108 was hard to start - just as if there was air in the system. No leaks were found but i discovered fuel was draining down the return pipe allowing air to get back up the pipe and into the filter.
Once the engine started, there was no running problems.
Forming an upward loop cured the starting problem.
(if the return pipe in the tank had been long enough to stay below the fuel level, this would have helped)
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sorry for quoting an older reply, curious to understand that.
Is there any diagram explaining what you typed?
I also have similar issues starting and no problems once running and I do have a 4m long return pipe but wasn't aware that fuel draining back to the tank could introduce air into the filter, how would that pass from the HP pump to reach the filter? confused!

cheers

V.
 
vas said:
sorry for quoting an older reply, curious to understand that.
Is there any diagram explaining what you typed?
I also have similar issues starting and no problems once running and I do have a 4m long return pipe but wasn't aware that fuel draining back to the tank could introduce air into the filter, how would that pass from the HP pump to reach the filter? confused!
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My return pipe was connected to the top of the tank, so it seemed that fuel was draining by gravity from the top of the engine fuel filter from where the return was connected. This then allows air to percolate into the filter over several hours, I only had starting problems when the engine had stood for several days.
 
ianj99 said:
My return pipe was connected to the top of the tank, so it seemed that fuel was draining by gravity from the top of the engine fuel filter from where the return was connected. This then allows air to percolate into the filter over several hours, I only had starting problems when the engine had stood for several days.
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Should the return be connected to the fuel filter?
 
pvb said:
Should the return be connected to the fuel filter?
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It's 6years ago, but I found a 4108 manual online to jog my memory. The return from the injectors is connected to the top of the filter with a restrictor in it and a connection for the tank return. This must loop upwards. I found the loop in a box of spares having been removed for some reason by the previous owner. It was then that I discovered it was the reason for the bad starting inspite of no fuel leaks and hence why there always seemed to be air in the filter.
(the restrictor stop excessive fuel being returned to the tank when the engine is running)
 
thanks, that explains.
An odd setup. My return pipe goes from one injector to the other and then a long pipe to the tank top (which btw is above the engine injectors not below). So no relation to my issues I guess.

cheers

V.
 
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vas said:
thanks, that explains.
An odd setup. My return pipe goes from one injector to the other and then a long pipe to the tank top (which btw is above the engine injectors not below). So no relation to my issues I guess.

cheers

V.
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No, doesn't sound like this is your problem. What engine do you have?
 
yanmar 2GMF on a Mase generator, so not mission critical, just annoying, although I think I found a tiny leak in the intake path and things are better. Haven't started it for a week now, will try tomorrow and see how easy it will be :)
 
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