Bleeding Yanmar 2GM

[lockie]

I've successfully bled my 2GM fuel system many times in the past as described in the Yanmar manual. So I was mystified this time when despite bleeding fuel from the top of the filter, I could not get it at the injector pipes. The prospect of an injector pump overhaul was really starting to spoil my day, but then I spied a bleed screw I hadn't noticed before, and which the manual does not mention. It's where the pipe from the filter outlet connects to the top of the injector pump housing. After bleeding it I got fuel from the injector pipes, and then hey presto she fired up a treat.

I guess the pro's know about this, but for your average mug like me, it could have been a wasted couple of hundred bucks for a mechanic to show me, or even worse a needless pump rebuild.

cheers, lockie

[never monday]

Originally Posted by lockie

I guess the pro's know about this, but for your average mug like me, it could have been a wasted couple of hundred bucks for a mechanic to show me, or even worse a needless pump rebuild.

cheers, lockie

it's NEVER wasted money when you learn something useful.

[GordMay]

Good on yah. ✓

From Yanmar Help

Bleeding Air from the Fuel: (GM series)
“Open the small BLEED SCREW on top of the engine mounted fuel filter and operate the fuel lift pump by hand. After the fuel filter has been purged of air, close the bleed screw (don't do it too tight, it's only little) and open the one on the fuel injection pump. Again, after the air has been purged, close the bleed screw.
The engine should now start, if not you will have to bleed the high pressure side as follows: Crack the pipe nut at each injector, open the decompression levers and rotate the engine with the starter motor.
When the air appears to have been purged (the fuel looks clear, not whitish), tighten the nuts firmly, close the decompression levers and start the engine. Check for leaks and clean up any spilt fuel.”
➥ BLEEDING AIR

and

'E' series only GM engine fuel return line non-return valve
“... If the engine starts then dies and bleeding the fuel solves the problem, this check valve may be faulty. It could be corroded or worn. Part Number 128296-59940 and 22190-120002 Seal Washer Qty -2-“
➥ REGULAR MAINTENANCE

[never monday]

Gord,
I caution use of the small 10mm screw on the filter housing. I try to get people to use the larger 12mm screw.
The 10mm has threads that are cast into the housing. These threads also on some housings do not make a full circle. Rather they are 150ish deg sections with gaps at each end. With just a slight over torque they will pull out of the housing.
The 12mm has tapped threads and is much stronger.

[GordMay]

Originally Posted by never monday

Gord,
I caution use of the small 10mm screw on the filter housing. I try to get people to use the larger 12mm screw...
... The 12mm has tapped threads and is much stronger.

Pictured here

[never monday]

[GordMay]

Originally Posted by never monday

PERFECT! Thanks.

[lockie]

[QUOTE=GordMay;537490]Good on yah. ✓

From Yanmar Help

Bleeding Air from the Fuel: (GM series)
“Open the small BLEED SCREW on top of the engine mounted fuel filter and operate the fuel lift pump by hand. After the fuel filter has been purged of air, close the bleed screw (don't do it too tight, it's only little) and open the one on the fuel injection pump. Again, after the air has been purged, close the bleed screw.
The engine should now start, if not you will have to bleed the high pressure side as follows: Crack the pipe nut at each injector, open the decompression levers and rotate the engine with the starter motor.
When the air appears to have been purged (the fuel looks clear, not whitish), tighten the nuts firmly, close the decompression levers and start the engine. Check for leaks and clean up any spilt fuel.”
➥ BLEEDING AIR

Good stuff Gord, so someone else besides me knows!

But Yanmar don't tell us in either the user manual or the shop manual. Hence my post.

cheers, lockie