Bleeding the fue lines on a Yanmar 3YM30

chesapeakesailor · 16-09-2006, 15:15

I am having ALOT of trouble bleeding my fuel lines on this engine after replaing the primary fuel filter. It is my first time doing this and have thus far been unsuccessful getting diesel to flow out of the loosened fuel injectors. I am using the priming pump and am having no luck even when pumping for half an hour at a time. I was also dumb enough to run the engine after that without priming the filter with diesel first - so I have no fuel left in my lines. Any suggestions...

Wahoo Sails · 16-09-2006, 17:23

I just did this. Buy, and add an outboard motor primer bulb in the fuel line where it exits your tank. A few quick pumps, with the apropriate bleeder loosened & your done. Worked so well for me, it made me wonder why all diesels don't have this arrangenment!
Bob & Lynn

EagleSailTwo · 16-09-2006, 19:54

You do not bleed the fuel system via the injectors. There is on the IP a 10mm bleed valve, just open it one turn CC and pump the fuel pump until you see no more air bubbles.

chesapeakesailor · 16-09-2006, 20:33

First suggestion sounds like a really good one. The second one also, but what is the 'IP' an acronym for? Thanks again!

Tropic Cat · 16-09-2006, 23:07

There is a 10 MM screw on top of the secondary engine mounted fuel filter which should be loose as you are operating the lift pump. Email me directly and I'll send you the Yanmar bleeding instructions.

Rick in Florida
rick@thepracticalsailor.com

Tropic Cat · 16-09-2006, 23:07

There is a 10 MM screw on top of the secondary engine mounted fuel filter which should be loose as you are operating the lift pump. Email me directly and I'll send you the Yanmar bleeding instructions.

Rick in Florida
rick@thepracticalsailor.com

billangiep · 17-09-2006, 04:18

From Yanmar Help...... http://www.yanmarhelp.com/s_bleed.htm

EagleSailTwo · 17-09-2006, 09:29

Quote:

Originally Posted by chesapeakesailor

First suggestion sounds like a really good one. The second one also, but what is the 'IP' an acronym for? Thanks again!

"IP" Injection Pump.

Alan Wheeler · 17-09-2006, 12:42

OK Chesapeaksailor, I think if I understand you correctly, you are trying to uise the lift pump to bleed air from the injectors. No it doesn't work that way. The lift pump is to bleed air from the fuel system to the injector (IP) pump. From the IP on, the fuel is at high pressure and the pump itself takes care of the air.
So you crack that bleed screw on top of the filter that Eaglesail noted and use the lift pump till all air bubbles are gone from there.
"Some" IP's have a small bleed screw on the body which allows the air to be removed to the pump. Some you have to crack the fuel line where it enters the pump body. From there on, the pump should be able to cope. It is usually older pump desings that need to have the injector bleed as well.
To bleed injectors, you have to be turning the engine over as you crack the nut at the injector. Modern engines can usually cope and you just need to turn the engine over for a slightly extended time till the engine fires into life. It may run ruff for a few seconds till all air is bleed through.

Chrisc · 18-09-2006, 00:38

Further to Wheels advise, and something I learned the hard way..
Don't crank the engine for too long without it firing up otherwise you run the risk of flooding the water-lock and without the exhaust gas from a running engine to ecacuate it, the water's got only one place to go...unfortunately.

Chris

Vasco · 18-09-2006, 05:55

Chris,

Good point and you can never be reminded of this too often. Usually when the engine won't start it happens at the worst time, like at two in the morning, a bad squall, and having to get out of someplace fast. In these circumstances it's easy to forget and keep cranking away at the engine. If the engine won't start after two or three cranks, go down below and shut off the engine cooling water intake! When it starts you can open it again. If you don't do this you run the risk of "hydrolocking" your engine and if it starts with water in the cylinders it'll bend your piston rods and shear your crankshaft and god knows what else. Don't ask me how I know.