Adding an electric fuel lift pump on older Hunter's with Yanmar diesels,

[swshogren]

Has anyone considered the addition of a small electric fuel lift pump on old Hunter's with yanmar diesels? have a 1984 Hunter 34 with a yanmar 3gmf. I have changed filters, bled air, and looked for leaks, etc. For the past week when trying to run upriver against the current of the Columbia River my motor is dying usually in the shipping channel. Some times it takes minutes, done tribes a couple of hours. My mechanic thinks I need to add an additional pump. And apparently, before I bought the boat or had one that the broker removed. Any ideas, suggestions or experiences to share? I am polishing the fuel while I write this to see if I got bad fuel. Help.

 

[kloudie1]

Has the little screen on the tip of the fuel pick-up tube been removed? Check that first..
I know that some folks have put a little Facet electric pump close to the tank so that it is much easier to bleed.
Kinda like this:

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[Alan Gomes]

Has anyone considered the addition of a small electric fuel lift pump on old Hunter's with yanmar diesels? have a 1984 Hunter 34 with a yanmar 3gmf. I have changed filters, bled air, and looked for leaks, etc. For the past week when trying to run upriver against the current of the Columbia River my motor is dying usually in the shipping channel. Some times it takes minutes, done tribes a couple of hours. My mechanic thinks I need to add an additional pump. And apparently, before I bought the boat or had one that the broker removed. Any ideas, suggestions or experiences to share? I am polishing the fuel while I write this to see if I got bad fuel. Help.

If the 3GM uses a mechanical lift pump (which I believe it does), then you do not want to add an extra pump in line with it. Rather, disconnect that pump altogether and *replace it* with an electric pump. By "disconnect" I mean leave it bolted to the engine but simply remove the input and output hoses from it and hook up the electric pump in its place.

The mechanical lift pumps can develop leaks in the diaphragm, which will in turn dump fuel into your crankcase. By disconnecting it you elimiate that potential failure.

There was a recent thread about this, which I'm sure you can dig up using the search function.

 

[Johnb]

If there is a useful gain from modifying your engine ( e.g. bleeding becomes much easier) then do it. I question whether you really will improve your reliability by changing something that has worked for 36 years. A new crankshaft activated fuel pump is a cheap and easy replacement. That is what I did about 10 years ago.

If you go electric do it right including proper wiring design and installation.

 

[Alan Gomes]

If there is a useful gain from modifying your engine ( e.g. bleeding becomes much easier) then do it. I question whether you really will improve your reliability by changing something that has worked for 36 years. A new crankshaft activated fuel pump is a cheap and easy replacement. That is what I did about 10 years ago.

If you go electric do it right including proper wiring design and installation.

If that is the original 36-year old pump then that alone is a good reason to make this mod. When the diaphragms fail with age the pump can dump fuel into the crankcase. No bueno.

With the electric fuel pump you can set it up with a diverter valve, with one side going to the high pressure injection pump on the engine and the other side going to the fuel return line. Add a switch to energize the pump from the engine compartment. Then, to bleed, just set the diverter valve to go to the return line and energize the pump. This makes priming a new filter and bleeding the engine a breeze.

Wiring up a new Facet electric pump is trivial.

 

[alexco38]

Change the diaphragm once every 30 years or so isn't too bad. Just don't wait until it break.
Diesel engine suppose to run with no electrical power at all.

You have to change the stupid timing belt on cars every 5 years or less and cost a lot more money.

 

[Alan Gomes]

Change the diaphragm once every 30 years or so isn't too bad. Just don't wait until it break.
Diesel engine suppose to run with no electrical power at all.

You have to change the stupid timing belt on cars every 5 years or less and cost a lot more money.

Of course, switching to an electric pump not only completely eliminates any worry of diaphragm failure but also makes priming the engine and new fuel filters a joy (with a minor wiring and plumbing change) vs. a tedious chore. The priming lever on the Yanmar mechanical lift pumps doesn't work worth a darn. I'm so glad to be done with it.

 

[Mike Oldak]

I also have an 84 H34 and had similar engine cutout problems. it turned out to be algae in the tank getting stirred up and clogging the filter. I had the diesel polished to remove the algae and always use an algae killer when I fill up.

 

[Johnb]

I wrote crankshaft driven and it actually is camshaft.

 

[artboas]

I wrote crankshaft driven and it actually is camshaft.

Was wondering about that. I have a crankshaft water pump on my Yanmar, but couldn’t conceive putting a fuel pump there

 

[Secret sail]

I had bleed problems too and thought about an electric fuel pump. I finally settled for an in line pear pump the same as on out outboards. Pump it three times and its done
Then I learn't how to bleed the yanmar by opening the decompression levers. Its a doddle. I wired a push button to crank the engine on the side of the engine compartment. Open the 3 decompression levers. Then with a 10mm spanner open the bleed screw and crank the motor for about 3 to 5 seconds... the diesel spurts out so just reclose the bleed screw. Close the compression levers and just restart the engine
I've since installed the fuel filter in front of the engine compartment for easy access
You can see the starter button just behind the coolant tank. The fuel filter in front for easy access.

 

[swshogren]

Secret Sail - Thank you for sharing the photo. The relocation of the fuel filter off the engine and on to the bulkhead is brilliant! Mine is down low on the starboard side of the engine requiring me to jam myself down into what little space I have in the galley to access it. The previous owner cut away part of the engine compartment to make it more accessible. Your solution is much more elegant and I am going to guess quieter when the engine is running.

Update: So what did I do? When I wrote my first post on this topic I was stranded 35 miles from home upstream on the Columbia River where tides and a strong current are both present and on the wrong side of a railroad bridge and a major interstate highway bridge. Following the advice of my diesel mechanic, I temporarily installed the electrical life pump AND ran the fuel pickup and return lines to a 5 gallon can of clean fuel. That got me safely through the bridges and almost home when I lost power in the river with barge traffic approaching - luckily we were at a point that sailing was an option - so up went the sails and we got home.

Discoveries: A bad case of algae in the tank as suggested above by Mike, a decaying hose line (at the ends where the clamps meet the engine) between the mechanical fuel pump on the engine and the fuel filter that was letting air into the system, a decayed bladder inside the original pump (any leads on rebuild kits??) and electrical issues with undersized started cables and cable runs that are too long and maybe a starter that needs replacing and the need to install an inspection hatch on the original fuel tank.

Good thing the winter rains have settled over Oregon as I'll now have time to sort this mess out at my home marina!

Any additional suggestions, advice or comments are welcome.

 

[Secret sail]

I had algae/bacteria too thick sludgy gluey substance in the diesel tank. Just stopped the engine on the way into the harbour!
Took out the fuel sender and had a look inside... fuel seperator blocked. It was quite easy to unscrew the rear bedroom to gain access to the fuel tank. Syphoned out the dirty contaminated diesel. Then took the tank home cleaned with detergent and pressure washer, dried it under the sun then used a gallon of bleach to clean each surface inside the tank at a time. I should be ok for a couple of years but i'll check this every season. Fuel additif everytime i fill up too !!!!

 

[Claude L.-Auger]

The priming lever on the Yanmar mechanical lift pumps doesn't work worth a darn. I'm so glad to be done with it.

I used to think the same until I realized that for it to work properly, the lift pump actuator has to be at the proper position on the camshaft. If you pump more than 2 or 3 times and do not get anything, rotate the cam 1 third turn (easy if you decompress the engine: I can do it manually). Chances are it will then give you good flow. If not, rotate one more turn and you're good to bleed easily. Of course I'm talking about the 3-cylinder 3GM30 Yanmar.

 

[Alan Gomes]

I used to think the same until I realized that for it to work properly, the lift pump actuator has to be at the proper position on the camshaft. If you pump more than 2 or 3 times and do not get anything, rotate the cam 1 third turn (easy if you decompress the engine: I can do it manually). Chances are it will then give you good flow. If not, rotate one more turn and you're good to bleed easily. Of course I'm talking about the 3-cylinder 3GM30 Yanmar.

Hi, Claude. Yes, I'm already aware that the position of the cam affects the pump. My statement takes that into account. By moving the cam into the right position it goes from completely unusable to merely terrible. At least this has been my experience on the two different 1GMs I've owned; perhaps it's different for other engines with different pumps. Plus, bear in mind that when you change a filter, there's no way you are ever going to be able to fill up that filter from completely dry to full. It simply doesn't produce enough suction. (Again, I speak of the pump on the 1GM. But I *think* that's the same pump the original poster has. Could be wrong about that, though.) So that means you've got to come up with a container of clean diesel somehow and prefill the filter (or filters, in most cases) even before you could think about using the lift pump lever to bleed out any air. That, and the fact that when/if the diaphragm fails on the lift pump, you can get fuel in the oil. No thanks.

With an electric fuel pump, a diverter valve, and a few minor plumbing changes, you get a system that is not only more reliable but far simpler to operate. And it does not come at great expense in either time or money.

Seriously, the way I have my system plumbed now with an electric pump, I actually look forward to changing my fuel filters! And if for some reason I ever had to do it in a seaway, I'd be especially happy for having made the mod.

 

[SabreToothedEngineer]

Some four or five years ago I was having a terrible time starting the Yanmar 3GMF in my '83 H34. The local Yanmar mechanic diagnosed a worn out fuel pump and recommended adding an electric pump after the primary fuel filter. We (the mechanic and I) couldn't get anything out of the mechanical pump using that little lever at all (and I know about the cam position). The new electric pump is wired to the ignition switch and to a breaker, so it runs whenever the key is turned on. The difference has been startling. The engine starts absolutely reliably in 1 - 2 seconds, and as has been pointed out, bleeding the system is dead simple instead of an ordeal. We had a reminder this summer of how important that pump is when we couldn't start the engine one morning at anchor in a remote spot. It took almost an hour to get the engine running, and when we did, we beetled straight for home instead of stopping for another night in a favourite spot, for fear of not being able to get it started again. The next day I diagnosed that one of the crimp connectors right at the pump had worked its way loose. I fixed that, and all's well.

The short summary is I'm a big fan and would heartily recommend adding one to an old engine.

 

[alexco38]

Amazing that people would spent all the effort, money and worries to replace filters, add chemicals and fuel polishing but ignore the O-ring on the deck fill.

After a fuel issue almost crashed my boat on a rocky shore 13 years ago. I removed and clean the fuel tank completely and treat it as clean as surgically possible.

Ever sine than I started to replace the deck fill o-ring every time I open the fuel cap. Not a single drop of sediment for all these years. Never replace the primary Racor filter, the fuel pump screen or the engine mounted filter. Engine never had a fuel issue.

At work our Standby generator store their diesel for years.

You can get a bag of dozen O-Ring at industrial supply for $10. I don't expect it to last longer than a single fuel interval.

 

[Globe Pilot]

Resurrecting an old post with my 2 cents. Last summer my alternator failed on the start of a long passage across Lake Ontario. With the light winds I would have been turning around if I only had an electric pump. An electric pump sounds like a useful addition, after rebuilding the mechanical pump.

 

[MFD]

Resurrecting an old post with my 2 cents. Last summer my alternator failed on the start of a long passage across Lake Ontario. With the light winds I would have been turning around if I only had an electric pump. An electric pump sounds like a useful addition, after rebuilding the mechanical pump.

I agree - make sure your mechanical pump is in good shape and consider the other pump a useful accessory.

Yammer 4JH4AE, came from the factory with an electric pump. Very useful for everyday stuff like (maybe) keeping a little load off the mechanical pump and obviously very handy when bleeding the fuel system. Meanwhile - the electric pump died one time a few years ago and the engine was a no-go. I had it fairly isolated and was thinking to simply bypass it with spare hose, but given closeness to shore/rocks, no sails on the boat at that time, and other things ended up getting towed in.

This was with the 'factory' pump (~10 years/1000-hours) from Yanmar. I replaced it with another factory unit, picked up a spare - but still have to test out if everything works bypassing it. The fuel tank is about 2-3 feet below the engine mechanical pump, the first filter about a foot above.

 

[jssailem]

You should be golden. Those pumps usually have a 4 ft plus lift capability.