I am wondering whether or not you need to bleed the lines after changing the fuel filter(s)for my diesel yanmar 9hp. If so, where can I get information about how to bleed the lines? I understand how to do a car brake system but how do you do it with the diesel engines. Thanks,
Changing filter on diesel fuel line(s)
- Thread starter WayneC
- Start date
- Status
A source would be to purchase a service ....
manual for your engine, which would explain the process. Easy to do once you know the steps. Replacing the filters will normally leave air in the system, similar to a brake system, that needs to be bled off. On our engine it was on the low pressure (inlet) side of the pump, or also on the inlet side of the injector(s). Terry
manual for your engine, which would explain the process. Easy to do once you know the steps. Replacing the filters will normally leave air in the system, similar to a brake system, that needs to be bled off. On our engine it was on the low pressure (inlet) side of the pump, or also on the inlet side of the injector(s). Terry
The answer is yes,
On the 1GM10 you have two bleed screws, one on top of the fuel filter housing and the other one on the fuel injection (high pressure) pump. Locate the the fuel transfer (low pressure) pump and you will find a priming lever under it. Open the bleed screw on the fuel filter and pump the priming lever until no air bubles come out of the bleed screw. Repeat the process for the bleed screw on the fuel injection pump. If you are having difficulty drawing fuel with the priming pump you may crank the engine a few times to let it work the pump.
On the 1GM10 you have two bleed screws, one on top of the fuel filter housing and the other one on the fuel injection (high pressure) pump. Locate the the fuel transfer (low pressure) pump and you will find a priming lever under it. Open the bleed screw on the fuel filter and pump the priming lever until no air bubles come out of the bleed screw. Repeat the process for the bleed screw on the fuel injection pump. If you are having difficulty drawing fuel with the priming pump you may crank the engine a few times to let it work the pump.
Forgot to tell you the bleed screws
are different from the ones used in automobile brakes. The screws have a phillips patern on the head and the bleeding hole is down in the thread area and is not visible until you start turning the screw out a few turns.
are different from the ones used in automobile brakes. The screws have a phillips patern on the head and the bleeding hole is down in the thread area and is not visible until you start turning the screw out a few turns.
Depends on the Engine
Modern Yanmars are self bleeding. To prove this on my 37 HP 3JH2E I changed filters, including the big Racor water separator but did not bleed the system. Then I turned off the raw water seacock and just turned the ignition key. The engine ran briefly and stopped, using up the fuel in the injector lines. Then I turned the key again and after about 10 seconds it started and ran perfectly. This is not a procedure to be recommended as the starter motor is not rated for continuous running and the muffler will fill up with seawater if the seacock is not closed. It would help to pull the valve lifter but I didn't bother to. Why did I do it? Well, if motor sailing on port tack and the fuel level is low, the pickup tube can suck air and the engine will stop. It would be a nuisance, possibly dangerous, to have to bleed the whole system whilst underway. However it did prove the point and verified Yanmar's claim for a self bleeding engine.
Modern Yanmars are self bleeding. To prove this on my 37 HP 3JH2E I changed filters, including the big Racor water separator but did not bleed the system. Then I turned off the raw water seacock and just turned the ignition key. The engine ran briefly and stopped, using up the fuel in the injector lines. Then I turned the key again and after about 10 seconds it started and ran perfectly. This is not a procedure to be recommended as the starter motor is not rated for continuous running and the muffler will fill up with seawater if the seacock is not closed. It would help to pull the valve lifter but I didn't bother to. Why did I do it? Well, if motor sailing on port tack and the fuel level is low, the pickup tube can suck air and the engine will stop. It would be a nuisance, possibly dangerous, to have to bleed the whole system whilst underway. However it did prove the point and verified Yanmar's claim for a self bleeding engine.
what I do
When I change diesel fuel filters, I use a "squeeze bulb", the ones used on outboard engine fuel tanks, to get the air out of the filter. I disconnect the hose from the filter to the lift pump and insert the squeeze bulb and when I get fuel from it, I reconnect the line to the lift pump. Works great. I am tempted to leave a squeeze bulb permanently connected but I've heard they may not be rated for diesel fuel.
When I change diesel fuel filters, I use a "squeeze bulb", the ones used on outboard engine fuel tanks, to get the air out of the filter. I disconnect the hose from the filter to the lift pump and insert the squeeze bulb and when I get fuel from it, I reconnect the line to the lift pump. Works great. I am tempted to leave a squeeze bulb permanently connected but I've heard they may not be rated for diesel fuel.
Del...
the squeeze bulb I just bought (Attwood) says it can be used for transferring diesel and is alcohol safe. If that's the case, it should be OK to install in the fuel line to ease the burden of trying to move fuel with the Racor's pump or the lift pump lever on my Yanmar. I plan to install it when I revamp the fuel system feed over the winter.
the squeeze bulb I just bought (Attwood) says it can be used for transferring diesel and is alcohol safe. If that's the case, it should be OK to install in the fuel line to ease the burden of trying to move fuel with the Racor's pump or the lift pump lever on my Yanmar. I plan to install it when I revamp the fuel system feed over the winter.
- Status