Purging fuel line from Racor to injectors (D2-40F)

[PaintedKite]

Hello! Can someone instruct me on how to purge/bleed a fuel system that's been opened up all the way to the injectors? I'm concerned there's a LOT of air in the system. This Volvo Penta D2-40F (saildrive) will not start.

I'm confident there's really nothing wrong with the engine and that I just need to systematically and correctly bleed the system all the way through the injectors.

I know how to purge the system after a routine maintenance (oil, oil filter, and fuel filter changes), using the manual pump and bleed screw. But I don't know how to purge downstream of the fuel pump.

Li'l help??

[Bellinghamster]

Purge everything up to and including the injection pump first. My preferred method is to use an electric fuel pump in line after the Racors but you can use the manual engine mounted lift pump as well. Disconnect the fuel inlet to the injection pump and run it into a bucket. Pump until you get clear fuel with no bubbles. This can take a LONG time if your Racors were empty and the fuel ran back down the pickup line from the tank. You can speed things up by manually filling your Racors filters with clean fuel.
Next reconnect the fuel line to the injection pump, open the bleeder fitting on the injection pump and manually (or electrically) keep pumping until clear fuel/no bubbles come out. Close the bleeder.
Now crack open the nuts (or bolts) on all of your injection lines at the injectors about 1/4 turn. Crank the engine (make sure stop solenoid or cable is in the "run" position) until fuel dribbles out the injection line-to-injector joint with no bubbles (fold a paper towel up under it to keep from making a mess). Once you have no air bubbles coming out, stop cranking the engine, tighten the injection line fittings back up and the engine should start right up. If it runs rough (not on all cylinders), crack each injection line one at a time while the engine is running to let any more air bubbles out of them. The ones that cause the engine to slow down when they're cracked open are fine. Any that don't cause the engine to slow are not getting fuel through the injector and probably have a bubble in the line (or a bad injector)

[DougR]

Bellinghamster has it mostly correct, so I’ll just add a few engine specific points....

The hand primer pump on the top of the engine fine filter should do the job for you...open the bleed screw on the top of the fine filter housing and pump the hand primer until you get solid fuel from the bleed screw, then close the bleed screw.
Now go to the high pressure injection pump. There is no dedicated bleed screw on the injection pump, but thats OK. If you follow the fuel hose from the engine mounted lift pump to the injection pump you will see that it attaches with a banjo fitting, and on the top of the banjo bolt there is another small steel bleed line that runs up to the #1 injector. This bleed line is attached with a 6mm banjo bolt, and this small banjo bolt should be loosened to act as a bleed point. Now pump again with the hand primer pump. This will push fuel from the hand primer, thru the lift pump on the side of the block and over to the injection pump. When you get solid fuel from the small banjo bolt, screw the bolt back down and snug it. Now you have bled to the injection pump.

Now go to the high pressure fuel line nuts at the injectors, and loosen all of the nuts a turn or so and give the hand primer another 6 or 8 strokes. Now you have to bleed the high pressure lines, and this is done by turning the engine over with the starter motor. First, close the seawater thru hull valve on the saildrive so you don’t fill the exhaust system with seawater, then place the throttle at about 1/2 throttle. Crank the engine over with the starter motor and watch for fuel spurting around the nuts at the top of the high pressure pipes. Rags or paper towels here will help prevent a mess. After you see fuel spurting at two of three of the injector nuts you can stop cranking and tighten all the nuts up. Now open the thru hull water valve and continue cranking the engine. It should start and might run rough, but should pick up the remaining cylinders without problem. As mentioned, if they all don’t pickup you can crack the nuts one at a time while running and clear any remaining air.

This should do it for you, but if it doesn’t you might consider that there is a problem with the stop solenoid system. The stop solenoid is an “energize to stop” design and normally won’t prevent the engine from running, but if for some reason it is energized when it shouldn’t be, then it will prevent the high pressure lines from filling with fuel. This could happen if a problem occurs with the MDI box, and that’s not unheard of on your engine. If the fuel lines fill, don’t worry about it.

[PaintedKite]

@dougr and @bellinghamster, thanks so much, guys! I will ask my first mate to help me try these procedures here in the pouring rain this afternoon.

BTW, I checked and yes, she's got the 2 banjo bolts atop the injector pump, exactly as you've described!

One follow-up question, if I may: what if the guys DID crank & crank the engine with the seacock open? How will I know if that happened? How big a problem is it?

[Now that I'm looking at it, it's a real pain to reach that seacock, plus the handle's up against a vent hose, so it's very difficult to operate. I'm reasonably certain they did not close it.]

[Sailor 99]

Originally Posted by PaintedKite

Hello! Can someone instruct me on how to purge/bleed a fuel system that's been opened up all the way to the injectors? I'm concerned there's a LOT of air in the system. This Volvo Penta D2-40F (saildrive) will not start.

I'm confident there's really nothing wrong with the engine and that I just need to systematically and correctly bleed the system all the way through the injectors.

I know how to purge the system after a routine maintenance (oil, oil filter, and fuel filter changes), using the manual pump and bleed screw. But I don't know how to purge downstream of the fuel pump.

Li'l help??

Your gonna laugh but I have been using these for years. The trick is to find one that is ok with diesel fuel.

https://www.amazon.ca/gp/product/B07...?ie=UTF8&psc=1

You have a leak at the fuel filter gasket and you will be a long time getting any pump after the fuel filter to let you know its leaking.
The engine pump with its little lever will never let you know Ever!

Put these upstream of the fuel filter and have an oil rag underneath .

[Bellinghamster]

Bummer about the engine intake seacock location. It amazes me how boat makers position them so poorly for something that should be exercised regularly and easily accessed in an emergency.
Many water lift mufflers have a drain plug in the bottom. If yours does, ull the plus and drain the water out into the bilge (may be yucky.. do at your own risk). You can leave the plug out when you crank to prevent water from backing up into the exhaust manifold. Pause cranking periodically to let the water drain. It will blow yucky water + exhaust when the engine starts so be prepared (with a rag over it) and don't run long with it out or you'll get sleepy...

[captmikem]

A bulb is fine, but for about the same cost, here is what I use.

a simple valve in parallel with the pump, easy to prime the filter including the final up to the HP pump on the engine. Quick and easy.

M

[Bycrick]

I use the same arrangement as Captmikem except I’ve inserted a small inline filter just before the electric pump so that nothing ugly gets into the pump. It’s worked that way for 20 years. Close the valve, loosen the top of the Racor, turn on the pump, wait until the bowl is "full", tighten the cap. Then keep pumping for a couple of minutes. The electric pump will fill the fuel bowl on the engine and any excess will go back to the tank through the return line. The pump switch should be near the filter so you can stop it when the filter is full. I don’t even remember having to bleed the downstream lines, even when I took I took out the injector pipes for painting.

[Madehn]

if you do have to drill the hole in the water muffler, you can close it by simply putting a large enough stainless steel screw in the plastic muffler- they are not under enough pressure for this to be a problem- you DONT want to get water in a cylinder and then bend a connecting rod trying to start it-- turns a minor issue into a real PITA. and very $$$$

[PaintedKite]

Just got a surprise I can't explain. Historically, I've always been able to hand-pump that little, black bulb atop the fuel filter to bring fuel up and out of the bleed screw. It's my understanding that this primes the fuel pump.

Just tried it now and, after only 2 or 3 pumps, all the "travel" went out of the black bulb. It doesn't pop back up after being depressed. I can still pump away at it, but the travel's gone from maybe 5-8mm (normal) to just a mm or so. Doesn't feel like anything's happening when I pump it. No fuel or air comes out of the bleed screw.

Never encountered this before. Any ideas? I've got a full tank of fuel, and the isolation valve is open. Racor was just cleaned and reinstalled with a new element. [I *believe* the Racor is full of fuel, but it's in an awful spot, and I've got a sprained back, so I'd rather not have to take it apart if I don't have to.]

[PaintedKite]

Just in case anyone's still here, I'd like to tell you what the problem was.

Got an excellent, certified Volvo tech in here this morning, and he performed a thorough, systematic diagnosis. He KNEW the problem was a blockage in the Racor before even opening the Racor.

When changing the element in the Racor, the guy who did the maintenance shoved a gasket in the annular space between the outer wall/housing and the internal element.

Well, of course, that annular space is where the fuel flows. So of course we couldn't prime the engine.

Buttoned-up everything. Drained the exhaust line (it was fine). Primed the engine up to the injector pump*, and she turned right over and ran fine. Totally smooth-as-silk.

Many thanks to all of you for increasing my knowledge of the system!

*P.S. -- How come nobody mentioned the bleed screw right at the inlet to the injector pump?? That's a pretty sweet feature.

[George DuBose]

[QUOTE=Dark Horse;3264383]Your gonna laugh but I have been using these for years. The trick is to find one that is ok with diesel fuel.

I also installed a bulb pump between my fuel tank and my primary fuel filter.

Boy...did that make bleeding the engine a pleasure.

The "tickle" on the fuel pump isn't nearly as effective or fast.

...but how does one know if the bulb will last with diesel fuel?

[Compass790]

[QUOTE=George DuBose;3268085]

Originally Posted by Dark Horse

Your gonna laugh but I have been using these for years. The trick is to find one that is ok with diesel fuel.

I also installed a bulb pump between my fuel tank and my primary fuel filter.

Boy...did that make bleeding the engine a pleasure.

The "tickle" on the fuel pump isn't nearly as effective or fast.

...but how does one know if the bulb will last with diesel fuel?

I didnt worry about it as rightly or wrongly I assumed that petrol ( gasoline) was more aggressive than diesel when I bought a bulb for $3 frm China.
It looks exactly the same as the Amazon one in the earlier link. Bought another one to use as a pre-oiler in the oil pump circuit but put hose clamps on it as didnt like the wire loops sealing the hosetails.
6 years later both bulbs still going but I did put isolation v/v's on either side as I'd been scared by all the fear mongering.
Better to have the electric pump for fuel as you can use if for backup to mechanical.
Bought an electric pump as shown in earlier post but it's in the spares locker to ensure the mechanical never fails whilst I'm alive.