2qm20 starting help

[brownoarsman]

Actually if you know of a good video for removing the injectors, please share it! I haven't been able to find a good how-to; lots of common rail stuff but little in the way of very basic stuff like: this is how to disconnect the fuel line, here's how to get the injector off, etc.


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[Wotname]

Going back to my first post, the easy way to check fuel supply problems is to rig up a simple gravity feed to the engine.

It can be simple as a clear tube connected to the inlet side of the engine mounted fuel filter and a funnel jammed into the other end. Hold vertically and fill funnel with clean diesel from a pint jug, bleed the fuel filter and try it out. If it runs for a minute or more then fuel supply is the issue.

Now move the funnel and tube further back down the supply line towards the tank until the engine fails again. Now you have the source of problem located.

Good luck and remember this is a simple engine.

[sammyo]

There are three locations to bleed on the 2QM20. In sequence, the small filter on the engine, the injection pump way down to the left side, and at the injectors. Take lots of rags and paper towels and pump lots at each point in sequence. Did you check the condition of the small filter?

[BurningDaylight]

Wotname, that sounds easy enough and will be what I try tomorrow. I can only hope its just dirty fuel. Would make me super happy

[BurningDaylight]

Sammyo,

The points I bled are the screw on top of the filter on the engine, screw that's on the left side towards the bottom of engine, where the fuel line goes to. Then the flare nut on the right side behind the air intake.

I read you are supposed to turn the engine by hand, but my hand crank chain is missing. Any suggestions? Thanks

[Wotname]

Originally Posted by BurningDaylight

Wotname, that sounds easy enough and will be what I try tomorrow. I can only hope its just dirty fuel. Would make me super happy

Just bear in mind the engine fuel filter may also be clogged up. In that instance you can try your temporary fuel supply funnel straight into the injector pump but do that as a last resort as the fuel is unfiltere. With clean fuel and only a short time, no real damage will occur.

Originally Posted by BurningDaylight

Sammyo,

The points I bled are the screw on top of the filter on the engine, screw that's on the left side towards the bottom of engine, where the fuel line goes to. Then the flare nut on the right side behind the air intake.

I read you are supposed to turn the engine by hand, but my hand crank chain is missing. Any suggestions? Thanks

Turn it over with the starter motor with the decompression lever(s) operated.

[BurningDaylight]

Originally Posted by Wotname

Turn it over with the starter motor with the decompression lever(s) operated.

That would be with the lever down (pushed toward back of engine), correct? I noticed when I had it down today and tried to start the engine they moved back up while cranking.

[Wotname]

Originally Posted by BurningDaylight

That would be with the lever down (pushed toward back of engine), correct? I noticed when I had it down today and tried to start the engine they moved back up while cranking.

Gosh, can't remenber but easy to work out. One way the engine is hard to turn over because of the compression and the other way it spins over really easy and fast and never starts. The lever holds the exhaust valve open so there is no compresion.

Primarily use is when hand starting. Operate the lever and start turning the crankhandle faster and faster until the engine builds up momentum (energy contained in the flywheel), put lever back and hopefully there is enough stored energy to turn engine over past compression and hey presto, it fires

Also useful when needing to turn engine over during maintenance without the engine starting.

Be aware that one shouldn't turn the engine over for too long (say 30 seconds) without it firing as the cooling water is still being pumped through the engine and being dumped into the exhaust system without any exhaust gasses to push it through the exhaust system. It can fill the waterlock etc and run back into an open exhaust valve - not good. If you have to operate the engine for longer, first disconnect the water feed into the exhaust elbow and just let it run into a bucket or bilge or whatever.

I hope I'm not telling you how to suck eggs but there some differences between this engine and motorcycles

[sailorchic34]

Verify that the stop pull is all the way in and not partly out. How new is the diesel fuel. You might check if it runs with one or the other decompression levels open.

From personal experience, if one cylinder has low compression, the engine will tend to die once the start button is released. This as there is still compression to slow the other cylinder down but not enough to fire off the fuel in the compromised cylinder.

The QM series is a stout engine and a bit heavier duty then the newer but still old GM series.

[brownoarsman]

If you are on your own and need to hold the decompression lever while starting the engine, terra nova shared the tip with me that you can bridge the starter solenoid between the ignition circuit and the cable from the battery. This way you can be at your engine, holding the decompression lever while cranking rather than in the cockpit. It will spark a bit, so is a fire risk if you have fumes in the bay, and also watch out for drive belts and moving things


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[charliehows]

When I got my 2qm20 6-7 years ago, it had a few problems. The fuel tank taps leaked air - engine stopped. The fuel lift pump gave up - engine stopped. When i replaced the fuel filter i wasnt careful enough about fitting the seal correctly - engine stopped. The steel washer on the bleed valve leaked air - etc (replaced with a teflon washer, hasnt been a problem since.). By the time I'd finished i replaced everything that could leak air between the tank and the main injector pump. Since then shes run like a train. My guess is that this engine has come to you with at least one or two of these problems. They are simple and inexpensive to fix. I'd recommend doing the lot including new fuel hoses, at least to the injector pump. Even if you dont fix the problem, you've removed a lot of future ones. (maybe leave the lift pump - they dont usually break, I think I replaced mine unnecessarily because something else was leaking - at least i've got the old one as a spare)

[lockie]

Not sure if this is relevant, but might be of use. My 2GM has, in addition to the air bleed screw on top of the fuel filter, a second bleeder, located where the flex hose from the filter enters the top of the injector pump.

This second bleeder is not mentioned in any of the bleeding instructions I have seen. Usually I don't need to bleed, but a couple of times I have had to do so to get the engine to run.

Cheers, Graeme

[charliehows]

oh yeah - before i even started working on the engine i fitted a new hand crank chain so i could turn her over by hand - i got my chain from Tsubaki, just took in the top crank fitting and matched it up. Buggered if i know how you'll ever bleed it otherwise. You can be about 99% sure your problem is an insignificant air leak in the fuel supply system.

[charliehows]

Lockie is right - actually bleeding is a 3 step job - I think its (1) bleed at the secondary filter, (2) bleed at the injector pump screw and (3) bleed at the end of line injector banjo til fuel comes out. Its written pretty well in the old user manual.

[Wotname]

Originally Posted by sailorchic34

Verify that the stop pull is all the way in and not partly out. How new is the diesel fuel. You might check if it runs with one or the other decompression levels open.

From personal experience, if one cylinder has low compression, the engine will tend to die once the start button is released. This as there is still compression to slow the other cylinder down but not enough to fire off the fuel in the compromised cylinder.

The QM series is a stout engine and a bit heavier duty then the newer but still old GM series.

For the OP, all of SailorC's post is very good advice.

If you have indeed lost one cylinder, then maybe a possible solution would be talking to AllenH in this thread http://www.cruisersforum.com/forums/...lp-145601.html
(post 11), could be cheaper than a rebuild and possibly simply bolt in.

Nevertheless, let's hope for a more simple solution!