Mechanical Fuel Lift Pump Replacement

Dec 29, 2008
806
Treworgy 65' LOA Custom Steel Pilothouse Staysail Ketch St. Croix, Virgin Islands
OK, so our mechanical lift pump on our Perkins Ranger 6-135 diesel had been leaking into the bilge for a few months. For those unfamiliar, the mechanical lift pump resides on the side of the engine, and has a short little lever that you can manually pump with your finger to pull fuel from the tank and push it up to the injector pump - assuming your finger doesn't wear out first. When air gets into the fuel line on many diesels, either from a loose connection, removing the line to do maintenance, changing a fuel filter, or running out of fuel, many diesels require you to pressurize the fuel lines all the way to the injectors and bleed the air from the system before the engine will start and run again. The mechanical lift pump provides one laborious way of doing this. An electric fuel pump is another. When the engine is running, the mechanical lift pump is driven by a lever which protrudes into the side of the engine to be driven by a cam, providing the pressure to the system while the engine is running.

So, last week while I was running briefly the engine on the mooring the pump finally gave up the ghost and started spraying lots of fuel onto the side of the engine, and apparently little into the injector pump, and the engine quit (I should add here that our bilge is dry, and I completely removed all fuel so we would not be at risk of a "spill" should the bilge pumps have occasion to run in the future). I had previously ordered a new pump, but when it arrived and I prepared to install it, I discovered that our pump has four bolts to hold it to the engine block, and the new one only had two. So, now I had a two-bolt pump that was no use to me, and still had the leak. I was having little luck finding a four-bolt pump online, but eventually contacted Tradewinds Power in Miami, who found the four-bolt pump and ordered if for me from England. So, I received the new four-bolt pump much quicker than I expected, and of course, the shipping was more than the cost of the pump.

It took 2 1/2 hours to remove the old pump. The hard part was reaching the bolts on the back side of the pump, next to the starter. The other challenge, of course, is that the generator is mounted about three inches from the side of the engine, and of course you need about three elbows on your left arm in order to get a wrench on the pump from where you are sitting or laying in the doorway to the engine room.

I applied a little gasket goo to the gasket and stuck it to the new pump, and placed one of the bolts into a hole to prepare to mount it. Here is the tricky part - you have to line up the pump lever in the hole in the block, line up the bolt holes, and screw the bolt into the first bolthole on the block. All with your left hand - and of course, without being able to see the work, since you can either look at the pump or reach the pump, but not at the same time, unless you have an arm on your forehead. And of course, the way your elbow and wrist bend, you can't hold the pump in place while turning the bolt, let alone get the bolt started in the hole.

I've concluded that what is really needed are two arms on the left side, each with at least two elbows, an preferably with an additional thumb and forefinger on the back of at least one of the hands. Plus, an eyeball in the palm would be handy.

It took another 3 1/2 hours to finish installing the new pump, and after doing a one-arm half push-up for 6 hours while reaching between the engine and generator, I had nothing left. I had to return the next day to attach the fuel line, bleed the system and start the engine - in all, another hour.

Before I have to do this again, I'm going to look into getting a second right arm grafted onto my left side.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
22,800
CAL 35 Cruiser #21 moored EVERETT WA
Brian I feel your pain and I got a terrific smile, no laugh at the experience. While I have the much smaller sister 4.107 Perkins, The engineers were nice enough to give me the same wonderful design features.
Hope you have success with the grafts.. Let me know who the doctor was... I may need to search him/her/it out.:clap:
 
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Likes: NotCook
May 20, 2016
3,015
Catalina 36 MK1 94 Everett, WA
In situations like this it is often easier to install two (or 4) studs in place of the bolts. The studs will hold the gasket without the goo and alignment with the bolt holes is guaranteed

Les
 

capta

.
Jun 4, 2009
4,907
Pearson 530 Admiralty Bay, Bequia SVG
I've used electric fuel pumps on a number of installations without problems. Keep in mind that most inline fuel pumps are pretty cheaply made, though reasonably reliable. However, I've used a much more expensive pump made for diesels that are super well built and reliable. They are about the size as a Rule 1200 submersible pump and around $125.00. I can't remember the manufacturer and have extremely poor internet here, so perhaps you can find them w/some searching. Those are the ones I'd use, if I were you, as you'd want the best for your main engine application, I would think.
Leave the manual pump on the block to cover the hole to the cam, but disconnect the fuel lines. You could carry a cheap inline fuel pump as a back up, though I've never had one of the expensive ones fail, even on high speed turbo diesels in SF boats.
 
Dec 29, 2008
806
Treworgy 65' LOA Custom Steel Pilothouse Staysail Ketch St. Croix, Virgin Islands
Brian I feel your pain
John, I failed to mention the extensive scrapes and scratches that resulted on both arms. I was also reminded that I shouldn't have been wearing my wedding ring while my hand was down in there, based on the jolt I got when it crossed the connections on, I think, the generator starter. I know better.

In situations like this it is often easier to install two (or 4) studs in place of the bolts.
Les, that is a great idea. I hope I never again have occasion to try out your idea!

I've used electric fuel pumps on a number of installations without problems.
Capta, the mechanical pump only cost $48, but the shipping was about $60. We actually do have an electronic pump, which is the transfer/boost pump on our FilterBOSS fuel management system. That is not needed for running the main engine, be it can be used for that. That is what I really used to pressurize the fuel for bleeding the injectors, after I verified that the mechanical pump was, in fact, pumping. Makes bleeding so much easier! That pump serves both the main engine and the Westerbeke 10K 220/50A genset. But to your point, I also do carry a spare electric fuel pump, just in case.
 
Oct 9, 2008
1,742
Bristol 29.9 Dana Point
In these cases, specialty tools can be useful. The box-end ratchet wrench and socket knuckles come to mind.
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