alistairmx
Member
How do you bleed the fuel system on this engine as I can't find a lift pump
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Detroit 8V71
- Thread starter alistairmx
- Start date
davidsharp
New Member
The marine versions don't have a priming pump. The fuel pump is a gear pump on the back of the block. If you have the filters full they will usually fire and work the air out.
buckfever
Senior Member
I have put low air pressure in the fuel tank and crack a line going to the injector pump and bleed the air out.
Ah, the memories of the old 318 running out of fuel. What really works well is obtaining an old primer pump from a refer engine or some other and constantly force feeding with fuel until it picks up. In the absence of a primer pump I have plumbed a hose into the top of one of the fuel filter housings, and the other end into a bucket or large funnel. Then while cranking keep fuel running into the fuel filter housing via the hose. This will require a helper to crank. Do not let air get back into the filter housing by letting your source run dry. Be patient, only crank for 20 or 30 seconds at a time, let the starter cool down, and repeat. If you do have some sort of primer pump that you can plumb into the fuel filter housing you basically do the same thing.
All the old 2 stroke detroits (53, 71, 92) were are difficult to prime unless an auxiliary pump was added.
Good luck!
All the old 2 stroke detroits (53, 71, 92) were are difficult to prime unless an auxiliary pump was added.
Good luck!
Birken Vogt
Charter Member
Last one I did was by pressurizing the fuel tank with air (blower nozzle and a rag, be gentle on the tank) (2 man job) and loosening the nut at the inlet to the gear pump, then tightening the nut up as fuel was still pushing out so as to not allow any air to return back in if the air was released from the tank.
I think it will pretty much start up on its own at that point, though if you want to be more thorough you can also loosen the jumpers at the injectors while cranking (rack in off position) and bleed them there too. If you do that it is pretty much guaranteed to start right up.
I think it will pretty much start up on its own at that point, though if you want to be more thorough you can also loosen the jumpers at the injectors while cranking (rack in off position) and bleed them there too. If you do that it is pretty much guaranteed to start right up.
if you can get hold of a Cat priming pump they are awesome for priming Detroits. You need to make a plate to bolt to the pump with the gasket, then some fittings for hoses, 1 suction hose to fuel supply then another with the same fitting as your secondary fuel filter inlet. I have one of these made up from a 3508, with a ball valve on outlet line and a pressure guage tee'd in. That way you can pressurise the fuel system to operating Psi, close valve and check injector lines for leaks, especially after injector change.
leaking fuel lines on these girls = fuel dilution in oil. (to do this you need to prime first, then block the return line)
But to answer your original question, the best way is to feed fuel into secondary fuel filter, (the supply for secondary is direct from fuel pump driven off blower) then it will flow through secondary, then into fuel rails in the cylinder heads, and return to tank. If there is a spare plug on the inlet of filter head it's even easier, remove that plug and feed fuel in there with some kind of pump. Of course you must make sure there is adequate fuel supply in tank, and filters full. It will fire straight away as injectors are full of fuel. A bit more complex setting it up, but it's also a one man job this way, and once you have it set up you have it forever.
leaking fuel lines on these girls = fuel dilution in oil. (to do this you need to prime first, then block the return line)
But to answer your original question, the best way is to feed fuel into secondary fuel filter, (the supply for secondary is direct from fuel pump driven off blower) then it will flow through secondary, then into fuel rails in the cylinder heads, and return to tank. If there is a spare plug on the inlet of filter head it's even easier, remove that plug and feed fuel in there with some kind of pump. Of course you must make sure there is adequate fuel supply in tank, and filters full. It will fire straight away as injectors are full of fuel. A bit more complex setting it up, but it's also a one man job this way, and once you have it set up you have it forever.
There is no place to bleed fuel on a detroit 2stroke.If you are changing filters on one,its best to do it on a warm engine,remove the old filter,replace with a new one,fill the filter with fuel,reinstall.When ready to start set the engine at 50% throttle,and hit the starter,it will sputter a bit till the air is worked out,but rarely will it stall doing this.Never try to restart at an idle,guaranted to stall,and plenty of cranking to regain the fuel supply.
oldtom
Well-Known Member
- Joined
- Oct 15, 2012
- Messages
- 115
- Location
- Australia
- Occupation
- diesel equipment maintenancesuperviser
you can remove fuel line coming from fuel tank to filters should be marked remove plug if fitted with two inlet ports and just pump fuel in can screw off filter 1/2turn to bleed air will flow though and to injectors and back to tank
Idaho Logger
Member
I made an adapter to screw into the secondary fuel filter and then screws into the hose of my fuel pump on the slip tank of my pickup. Screw them together start the pump and hit the starter. Works a lot of the time