Change filter and bleed. Scared!

[SV Bacchus]

Originally Posted by a64pilot

The other thing is hear about that gives me the willies is that some people will use straight injector cleaner thinking sending it in pure is a good thing.

A very salty old Diesel mechanic told me to place the new filter in the bowl and fill with ATF out of a sealed (new, not used) bottle. He said it is as clean as can be and the ATF will take care of some of that lubrication and valve cleaning business people always talk about..

[thinwater]

Just a few things for discussion:



"... There IS one caveat. If when you crank the engine to bleed the injectors, try not to crank too long. Crank too long and you might suck water into the engine. If needs must you can TEMPORARILY close the engine water.html" target="_blank">raw-IRJDSUNE9932123321222xxeww-water hull.html" target="_blank">thru-IRJDSUNE9932123321222xxeww-hull. Just remember to turn it back on when the engine fires...."


How long can a diesel crank and/or idle without water? The pump will be dry, but a few minutes at low RPM should not be a problem, since it will be wet. Heat generation at idle is pretty minimal.





"... We've been instructed to NOT allow unfiltered fuel to a diesel engine. "Clean" new diesel is not filtered. Might be overkill, and I know bazillions of folks use "clean" (but unfiltered) diesel to pre-fill a new filter... but we've chosen to follow the more cautious instruction...."


You could filter the diesel. A coffee filter is about 40 micron. I have a set-up in my shop using a gallon jar with a bottom fitting, an in-line fuel filter that is 2 micron, some hose, and a valve. I used it for numerous tests (long story--don't ask) but it would also be handy for something like this. I also suppose many fuel polishing systems have a bleed somewhere that can supply filtered diesel. Obviously, meticulous cleanliness is vital.

[trikola]

I would add one point to the start of your list: make sure your start battery is fully charged and in reasonably good condition. You may need to crank more than normally. Best to have shore power during the procedure.

[Primal Alliance]

My 3YM 20 never needs the injectors bled. I remove both the primary and secondary filters, fill their holders with fresh clean{you don't need to filter it-that's what the filters are for in the first place}fuel, close the big filter not mounted on the engine, push up and down on the hard to get at little pump handle after opening the bleed screw on the small engine mounted filter, and pump until no air bubbles come out{if nothing comes out rotate the engine because the lobe on the hand pump is off from the lobe on the cam from the engine that drives it},and then crank. Yes, the post that says you shouldn't crank too long is correct. But my Yanmar has always started after hiccuping for a few moments{you may and probably will have to crank more than once}and then it will run rough for 10 or 20 seconds and then after that always runs smoothly.

[a64pilot]

Originally Posted by boatpoker

It is filtered by the time it gets to the engine unless you bypass your new filter and I can't see why anyone would do that.

You bypass the filter by filling it, filters usually filter on the outside of course, not the inside, the reason is there is more surface area on the outside. By pouring the fuel on the inside it bypasses the filter.

But there is no need, every Diesel I have ever had, had a manual pump to bleed filters, and many add an electric pump to make it even easier. It’s just open the bleed valve and pump until fuel flows out and your done, there is no need of pre filling a filter and maybe spilling fuel etc, and working the little manual pump is easier than pre filtering fuel.

[Boatyarddog]

Originally Posted by joeniver

I am kinda nervous to do my first "on engine" fuel filter change. Please let me know if the following steps are correct for doing the change and bleeding the line to the filter and to the injector pump. I was told by PO that I should not have to bleed at the injectors.

Any comments, critiques, suggestions, Hell-Nos sincerely welcomed.

Yanmar 3HM F


Step 1:
Turn off engine. I know it is working.

Step 2:
Presoak the new fuel filter in a clean jar of diesel fuel. I know that they recommend to fill the cup with diesel after putting the new filter in, but I am adding a little insurance by doing that and pre-soaking.

Step 3:
Take off fuel filter cup from engine. Remove old filter, trying not to add air to fuel left in the cup.

Step 4:
Put new filter into container and add diesel fuel to the very top.
Go slow so no air gets into the container or into the filter. Tighten container.

Step 5:
Open bleed screw on fuel filter and pump lever on lift pump till all bubbles stop coming out. While continuing to pump, close bleed screw on fuel filter cap. I believe that the bleed screw is the one in the back, nearest to the block?

Step 6:
Open bleed screw on injector pump while pumping lever on lift pump. Continue pumping til no more bubbles come out of the bleed screw on the injector pump. Close bleed screw while pumping.


Step 7:
Start engine

See pictures below

That's a Yanmar, no big surprises for these.
You've got the procedure down.
Yanmars are generally forgiving, will tolerate a Little air, and will self bleed well.
If you should get some air or no start, that's not likely, but usually they run for 45 sec then die, if you've got air in the injection lines.
If so then crank, and loosen the injector coupling nut till you see clear fuel.
Be sure to make sure you close the water uptake till she starts. Then open.
Then enjoy!
SV Cloud Duster !

[Capt.Don]

You usually don't need to bleed the injectors, step 6. You may have to bleed the primary and try starting a few times.

I painted the bleed screws with red nail-polish. Makes it easier to find, especially while underway.

On the Yanmar, the manual bleed pump is dependent on the orientation of the crank shaft. If you pump the lever and there's little or no pressure, turn the flywheel a bit (or crank over the engine). You should have a good stream.

Be sure to let the engine run for about 15 minutes after you change the filters, to make sure there's no air remaining. If the engine stalls, rebleed.

This is something everyone needs to know how to do -- we had to cut short a trip because I didn't know how to bleed the engine (long time ago).

Don

[Redline452]

Originally Posted by Capt.Don

On the Yanmar, the manual bleed pump is dependent on the orientation of the crank shaft. If you pump the lever and there's little or no pressure, turn the flywheel a bit (or crank over the engine). You should have a good stream.
Don

What he said. I've changed filters on my 4JH2TE then priming with only the manual pump - if you don't run the engine, no air will get to the injectors. What isn't used by the injector pump is returned to the tank, so just keep pushing the little lever, making sure it's not on the "high spot" of the crank - a friend pumped that for a half hour to no effect. You should hear/feel the squirt of the fuel moving through.

[MarkSF]

Step 8 : run the engine in gear for 20 minutes.

Mine often cuts out after about 10 mins. Despite my best efforts to bleed the system, it seems there's often a little air left that must then work its way through.

I then do one more quick bleed at the HP pump, and all is well after that.

[Cheechako]

Your method sounds about right. I've never presoaked a filter but highly recommend fill the filter with clean fuel for sure.
-Trying to pump fuel with that little lever is not often very effective. Most of the time it stopped pumping and you could feel it not pushing any fuel. If you fill the bowls well you may find that you can just start your engine. My Yanmars always started fine.
-If not sure, start the engine and crack each injector nut a touch until fuel comes out. -Or have someone crank the engine while doing that if it doesn't start right up. (be careful you dont crank too long without it starting or you can get water in the engine if the muffler fills up!)

Finally, make sure you run it a long time at the dock before going out. Sometimes unfull filters will let the engine run for a while and then sure enough... right when you almost get out of the marina the engine starves for fuel and dies!

[CassidyNZ]

Like I mentioned in post #5, I have a squeeze bulb as used on outboard motors, installed in the incoming line between tank and 1st filter. It is a simple, inexpensive addition that far and away exceeds the Mickey Mouse little lever on the lift pump.

A few quick squeezes with the filter bleed screw open primes the system beautifully.

[roverhi]

On my 3GM only have to bleed at the engine filter. Yes, the bleed screw is the inboard one that's partially obstructed by the engine to make it a PITA to get at. The manual pump on both my 3 and 2 GM seems like it's not working with a very short stroke and little resistance but it is. Fortunately it works after a fashion and with my tanks above the engine fuel will syphon after a little pumping. Only once have I had to bleed all the way to the injectors but that was after running completely out of fuel.

[desodave]

Originally Posted by ChrisseH

I have never bleeded my Yanmar 3JH4E when changing fuel filters. Just run your engine warm, stop the engine, change one of the filters and restart. In 15 to 30 seconds the fuel pump has sucked out all air from the fuel line and the engine is running smoothly again. This works both when changing primary and secondary filter, at least when changing one filter at the time.

Caveat - I fill the changed filter housing with diesel first. Being relatively non-mechanical, I was scared to do it on my 3JH4E the first time, but it really is an easy process. Biggest issue has been not spilling fuel into the bilge changing the primary and putting absorbency sheets in the right places.

Warm engine first, turn off fuel at tank, drain filter housing on primary a bit through bottom of bowl(I use small yogurt containers because they flex around obstructions), take old Racor off carefully (with o-ring), drain rest of fuel, re-attach bowl to bottom of new filter, fill with diesel, lube o-ring on new filter, put back on tightening by hand, turn fuel back on at tank, start engine and let it run for a few minutes. Then do the secondary filter, which is way more accessible, effectively the same way - doesn't have a bowl on it so just take it off, get the new one and fill with fuel and screw back on by hand. Don't do them too tight or they will be difficult to take off next time. I've never had to bleed the engine after doing it this way.
Get used to the process - rough seas can stir up debris in the tank and clog the filters. It's comforting to know that you can pull off a quick change, if necessary.

Go for it !!

[Boatyarddog]

Originally Posted by cabo_sailor

Are you sure about Yanmars self bleeding? Mine was a 3 cylinder from maybe the early 80’s and it certainly had to bleed the injectors. My current Westerbeke 46 supposedly doesn’t need bleeding but for a couple minutes with a wrench it sure helps.

But your definitely right to suggest don’t overthink it. Apologies to the OP but I had this picture of a bomb disposal procedure with sweat pouring all over [emoji849]

Quite correct, however don't think you can just plug in a filter an go.
You MUST bleed the filter can of air.
If you don't you will have to bleed the system of air most certainly.
If you miss a bubble or two the engine may stall, it may stumble and recover, or be just fine.
At this point you'll most likely see air at the injectors.
Bleed this and you'll be on your way.

Bares repeating do not over crank the engine without it starting.
The danger is backing water into the Engines back cylinder, and Hydrolocking.
Cheers,
SV Cloud Duster

[sailcrazy]

Following. Even though I've watched mechanics change the filter(s), they have never done any purging the air out of the lines.....they just hit the start button and my 4JH-TE starts! Like the OP, I've always been nervous and reluctant to change the filters....just in case. To assist, I bought a small free-flow faucet pump and installed it between the 2 filters. And so far, no issues!!!