Yanmar 2GM injection pump issue?

kcford · #1 (**permalink**) 05-01-2011

Thought I might find answer searching forum, but didn't.
The problem: No fuel to injectors.
Background: Clean tank, fuel, filters. Motor was running fine. Sucked air into fuel system (fuel tank issue, beyond scope of problem here). This has happened twice before recently. Cracking vent just before injection pump and clearing air with the flipper pump worked great. Then about 15 seconds of cranking would clear the balance of air and motor would start and run normally.
The problem: Last week, same issue - sucked air. Bled to injection pump as before. Motor did not start as before. Cracked fuel line at injector and used flipper pump for what seemed like 1000 strokes. No fuel. Then I tried cranking motor with fuel line cracked at injector. Lots of cranking, NO fuel. Verified had fuel to injection pump.

What could this be besides failed injection pump?
Would running out of fuel cause injection pump failure?
Is there any procedure short of injection pump rebuild/replace that could get me going?
Finally, if it is injection pump, what would be best DIY procedure to get going. No Yanmar experts around here. I've pretty much got to fix it myself. Fairly mechanically savvy... not afraid to dive in. Just want to be smart about it. Thanks in advance for any guidance.

denby · #2 (**permalink**) 05-01-2011

Are you bleeding the fuel line step by step starting just after the lift pump?

kcford · #3 (**permalink**) 05-01-2011

I'm bleeding only at the engine mounted fuel filter just before the injection pump. Bled until i got all fuel with no bubbles there, which has always worked bofore. I don't see the point in bleeding further back if I have fuel with no air at injection pump. Am I missing something?

denby · #4 (**permalink**) 05-01-2011

No, I missed read your post. You have to bleed all the way to the injectors. There are a couple of ways to do it. Let me find the thread that explains it. In the mean time I hope Mainsail chimes in or someone who is better at it then me.

denby · #5 (**permalink**) 05-01-2011

KC, try this thread, let me know if it is helpful.

http://www.sailnet.com/forums/gear-m...ar-engine.html

JimsCAL · #6 (**permalink**) 05-02-2011

If there is enough air in the lines between the injection pump and the injector, the air will just compress and the pressure won't increase enough to pop the injector. That's the reason for bleeding the system completely.

kcford · #7 (**permalink**) 05-03-2011

OK, I got it running last night. In the past, bleeding only to the engine mounted filter always worked. This time, there was still air in line from filter to injection pump. Cracked it at inlet to injection pump (didn't realize there was a bleed screw there), found air, bled. It then cranked with no problem. Don't know why this incident was different from past times, but it was. Now I know. Thanks for your input.

JimsCAL · #8 (**permalink**) 05-03-2011

Good to hear!

badsanta · #9 (**permalink**) 05-03-2011

Just a note. You cannot use the finger pump to get fuel through the high pressure injector pump. It is to get fuel to the injector pump but you cannot pump it enough or make enough pressure to go through the high pressure pump. You you have to crank the engine and loosen the nut at each injector to release the air. .

You also have to be careful with all that cranking that you don't fill up your exhaust with water and it backs up into the motor and hydro-locks it.

Most people that get water in their engine have caused the problem themselves from excesive cranking.

kcford · #10 (**permalink**) 05-03-2011

Make sense about not being able to pump past injection pump with the flipper. I tried it because a read a post stating you could. Also, I cranked way too long without closing the raw water seacock. Didn't get water in cylinders for some reason. I'm feeling pretty lucky right now. Gonna go sailing tomorrow after work. Thanks again everyone.