Ford Lehman bleeding/priming fuel system?

[Caribe]

Hi! I just changed filters and now won't start...I thought there was some air in filters so I refilled and tried bleeding with the manual pump lever. Getting fuel from top of filters and at front of injector pump. But no fuel at top of pump with lever or by cranking...Does injector pump need to be primed?
thanks!

 

[FF]

The lever on a fuel pump that uses (like most) a lobe of the cam shaft may not work, IF the cam is lifting its drive lever.

Just bump the engine and you may feel the manual fuel pump lever work better.

Simply loosening the nuts on the injectors (just a bit) will usually allow the injection pump to push any air out at the loose nut.

When fuel, with no air bubbles spurts out , tighten the nuts and it should run.

 

[jleonard]

See below for bleed screw location

 

[Caribe]

thanks Jleonard and FF. The lift pump seems to be working but no fuel coming from bleed screws...I'm going to try priming the pump w fuel from bleed screw holes...I'll let you know...

 

[Caribe]

Lever on pump working but still no fuel coming out of pump bleed holes or top of pump when lever depressed.

 

[Capt.Bill11]

You very rarely have to bleed the injectors on a Lehman. Bleed the filters on the engine one at a time starting with the one that might be slightly down hill from the next one and first in line after the fuel pump. Then bleed the second filter. After that bleed the the injector pump.

You can roll the engine over to bleed the pump if you have a second person handy. Have them hold the throttle about 2/3 advanced while starting the engine. The instant the engine fires off, back down the throttle to almost idle and close the bleeders. Then let it run for at least 5-10 min. To make sure you have all the air out.

 

[Capt.Bill11]

Lever on pump working but still no fuel coming out of pump bleed holes or top of pump when lever depressed.

Bleed one thing at a time.

Start at the fuel filters just down stream of the pump. One filter at a time.

The lever can move freely but if the cam is not in the right position you will not pump any fuel.

 

[what_barnacles]

It takes lots of pumps to fill the primary filters with that little lever.

 

[BruceK]

It takes lots of pumps to fill the primary filters with that little lever.

My Racor primaries have their own pumps.

 

[av8r]

The lift pump lever should always move, but if the camshaft is in the wrong position the pump lever will move and feel like it is pumping but nothing will happen. Use a tie-wrap to hold the fuel shut-off solenoid in the off position and use a wrench on the crankshaft bolt to turn the crankshaft 1/2 turn. Pull a bleed screw on the filter and try again. If still nothing at the filter, turn the crank another 1/2 turn and try again.

 

[Bay Pelican]

Several Lehman owners, including myself, have put a 40gph Walbro pump into the fuel supply system for the Lehman. Thus when I have to bleed the Lehman I turn on the electric pump and the fuel flows.

My set up allows me to bypass the electric pump or have it on line depending on what I am doing. Thus it can serve as a replacement for the on engine fuel pump if necessary.

A third virtue of the electric pump is that it allowed me to temporarily overcome an air leak in the system by virtue of the pressure from the pump.

 

[what_barnacles]

My Racor primaries have their own pumps.

Yeh, not sure why the racors with the priming pump arent standard equipment on boats. They are on diesel rv's even going back 20+ years.

 

[catalinajack]

Several Lehman owners, including myself, have put a 40gph Walbro pump into the fuel supply system for the Lehman. Thus when I have to bleed the Lehman I turn on the electric pump and the fuel flows.

My set up allows me to bypass the electric pump or have it on line depending on what I am doing. Thus it can serve as a replacement for the on engine fuel pump if necessary.

A third virtue of the electric pump is that it allowed me to temporarily overcome an air leak in the system by virtue of the pressure from the pump.

I did the Walbro "upgrade" earlier this year. No more bleeding nightmares! I elected to by-pass the mechanical pump completely. I may, in fact, replumb it to allow the use of the mechanical pump in the event a Walbro fails. Walbro pumps are highly reliable but failures do occur from time-to-time.

 

[RT Firefly]

Greetings,
Mr. C. In lieu of cranking the engine over by hand, buy one of these:

12 Volt Remote Starter Switch

 

[SCOTTEDAVIS]

Lots of great advice given above!!

You must bleed any air out of the injector pump if you changed the on engine fuel filters or the engine won't run. Air is compressible and will not allow the pressure to build up enough to overcome the springs in the injectors (it acts like a cushion) so you really need to follow the advice given and bleed from the furthest filter to the injector rack according to the given instructions. Air in the rack will not work itself out until the engine starts on at least a few cylinders.

Opening the throttle from half to full while cranking after all bleeding is complete this is important and will not cause a fast screaming engine but will allow it to start and then you can reduce throttle as it picks up RPM.

Be careful with too much cranking as you are adding water to the exhaust system without the combustion gasses purging it out, some systems will allow water to reach a high enough point to flood the entire system and run back into the open exhaust valves of the engine. This can happen if the high point of the system is lower then the point where the exhaust leaves the boat. If this is the case close off the intake for the cooling system while cranking, remember to open it at the first sign that the engine is ready to run.

Don't worry it will start and then you will know how the next time. We have all been there at one point or the other.


I love my electric priming/running pump. Makes this easy peezy.

 

[Caribe]

Thank you all for such great information. As it turned out I am such a dunce and completely to blame! I left the o ring off the mandrel on the last fuel filter and that pretty much choked the fuel. Once I found that, I purged the air and she started right up...Calypso takes care of me in equal measure to to my efforts...If only she had a real mechanic for an owner...

 

[kulas44]

You still need the Walbro pump. If you had it you would have seen the leak from the missing o ring. I will not own a diesel engine without an electric priming pump.

 

[what_barnacles]

I did the Walbro "upgrade" earlier this year. No more bleeding nightmares! I elected to by-pass the mechanical pump completely. I may, in fact, replumb it to allow the use of the mechanical pump in the event a Walbro fails. Walbro pumps are highly reliable but failures do occur from time-to-time.

I would buy a spare walbro.

When it fails you just stop. When the mechanical fails it can flood your crankcase with fuel.

 

[what_barnacles]

Thank you all for such great information. As it turned out I am such a dunce and completely to blame! I left the o ring off the mandrel on the last fuel filter and that pretty much choked the fuel. Once I found that, I purged the air and she started right up...Calypso takes care of me in equal measure to to my efforts...If only she had a real mechanic for an owner...

thats easily rectified. Simply sit down next to the engine and smash your forehead on the fuel filter. You will gain both the ability to never forget an oring and the socially acceptable (at least in our circle) forehead branding of "I'm a bonifide mechanic now".

 

[Capt.Bill11]

I would buy a spare walbro.

When it fails you just stop. When the mechanical fails it can flood your crankcase with fuel.

You don't have to have one or the other. You keep the mechanical pump as your main pump and plumb the electric (it doesn't have to be a Walbro) so you can valve it in and out of the fuel line system as needed.

 

[what_barnacles]

You don't have to have one or the other. You keep the mechanical pump as your main pump and plumb the electric (it doesn't have to be a Walbro) so you can valve it in and out of the fuel line system as needed.

When (if) the diaphram cracks on the mechanical it can flood the crankcase with fuel. That is impossible to do with the walbro or any external pump.

 

[markpierce]

A small pump for now-disconnected fuel polisher is plumbed to prime the engine (as well as to transfer fuel among tanks), assisting the engine-housed thumb pump.

 

[Capt.Bill11]

When (if) the diaphram cracks on the mechanical it can flood the crankcase with fuel. That is impossible to do with the walbro or any external pump.

That doesn't change the fact that you can have both pumps if you wish.

Besides, failure of the mechanical fuel pump on a Lehman is fairly uncommon. At least that is what I've found in my 30+ years of dealing with them.

 

[Marin]

Replacing the FL120's engine-mounted, multi-piece CAV canister filter setup with the spin-on adapters and spin-on filters makes it much faster to blleed the fuel system after a filter change because the spin-ons can be filled with fuel before installing them.

I hated the original CAV setup and when Bob Smith told me one day about the spin-on adapters jumped at the chance to ditch the CAVs once and for all. According to Bob it's one of the four best improvements that can be made to an FL120.

 

[Wxx3]

Several Lehman owners, including myself, have put a 40gph Walbro pump into the fuel supply system for the Lehman. Thus when I have to bleed the Lehman I turn on the electric pump and the fuel flows.

My set up allows me to bypass the electric pump or have it on line depending on what I am doing. Thus it can serve as a replacement for the on engine fuel pump if necessary.

A third virtue of the electric pump is that it allowed me to temporarily overcome an air leak in the system by virtue of the pressure from the pump.

Yep, I also have done exactly that.

To clarify, it is plumbed as an extra loop in the line, so under normal conditions, it's still gravity feed, but when changing filters, I close the one valve and open the two in the loop so the pump, pressures the system.

Even with all my fuel shenanigans, I've never had to prime injection pump.

 

[catalinajack]

I would buy a spare walbro.

When it fails you just stop. When the mechanical fails it can flood your crankcase with fuel.

Which is another reason I bypassed the mechanical pump. I think I even have a spare one aboard which I should sell to be replaced with a spare Walbro.

 

[catalinajack]

Replacing the FL120's engine-mounted, multi-piece CAV canister filter setup with the spin-on adapters and spin-on filters makes it much faster to blleed the fuel system after a filter change because the spin-ons can be filled with fuel before installing them.

I hated the original CAV setup and when Bob Smith told me one day about the spin-on adapters jumped at the chance to ditch the CAVs once and for all. According to Bob it's one of the four best improvements that can be made to an FL120.

Did this too. It is a tremendous improvement. Between the Walbro pumps and the spin-ons, the process is now quite simple. Plus, you don't have to mess with the top and bottom square o-rings.

 

[Bay Pelican]

Replacing the FL120's engine-mounted, multi-piece CAV canister filter setup with the spin-on adapters and spin-on filters makes it much faster to blleed the fuel system after a filter change because the spin-ons can be filled with fuel before installing them.

I hated the original CAV setup and when Bob Smith told me one day about the spin-on adapters jumped at the chance to ditch the CAVs once and for all. According to Bob it's one of the four best improvements that can be made to an FL120.

Replaced the multi-piece CAV canister filter setup with a Racor 500 filter assembly, thus using the same filters cartridges for both secondary and primary fuel filters. Also very easy to change and monitor.

 

[Larry M]

You don't have to have one or the other. You keep the mechanical pump as your main pump and plumb the electric (it doesn't have to be a Walbro) so you can valve it in and out of the fuel line system as needed.

Very easy. Use one 3 way valve or two ball valves on either side of the electric pump.

 

[Capt.Bill11]

Changing to spin ons is a great improvement. You can also make the engine mounted filters self bleeding like on the 135 Lemans.