What just happened?
I have an 1982 Oday 28 with a universal 5411 diesel. In 2007 I swapped out the motor with a rebuilt 5411 as I didn't want to change stringers or re-engineer the powertrain setup. The motor went in with no problem and it has been running well since then. I have changed the oil every year, and the fuel filters every 2 years. Last year I noticed that the water pump was leaking and the injector on the back cylinder was leaking also. So I planned to fix these 2 issues this spring.
Last weekend I took out the brand new Oberdorfer pump and all the fuel filters. I swapped out the pump and changed the filters. Bled the fuel system and she started up with no issues. I had also replaced the fuel return line as I thought that maybe that was the leak in the back injector. I ran the motor for about an hour, and the pump did fine and she sounded normal.However, the back injector was still leaking and the fuel was smoking off the back of the motor. So I started to look at getting the injectors serviced. In my research I found an article that showed the "5411" is really a Z500 Kabota motor, and the injectors are readily available and $44.00 plus shipping. Seemed like a great deal to me, so I ordered one. It got here yesterday and it looks exactly like the ones I have now. I measured and checked and it seems to be a perfect fit. So now I'm excited to get this project off the list.
At the boat I pull the old injector, install the new one and bleed the system. I make sure everything is tight and kick up the throttle and hit the glow plugs and fire it up. She stumbles for a second or two and then takes off! Runs smoothly and responds to the throttle just fine. I check to make sure I have water out the exhaust and I do. So I jump in and grab my spotlight to look for leaks and make sure everything is holding together. As I am looking at the back injector (it's not leaking!) there is suddenly a huge "WHACK" and then the motor starts knocking like it's coming apart. My heart tries to jump out of my chest and I pee my pants right there. In a huge panic I jump for the throttle and shut it down as fast as I can. It knocks badly all the way down until it stops.
I sit there for a minute, feeling my sailing season slipping away from me. I cannot fathom what is in store for me. My engine compartment seems like a deep dark hole that has just devoured my excitement for spring. So I guess I might as well check and see what was out of whack. I check the temperature gauge and it's sitting at 135 degrees just like it always does. I check the oil dipstick. Plenty of oil and I check it closely for metal. None. Check for water in the oil. None. I grab the belt and try to pull the motor over. It moves and I can push it through both the compression cycles. I am at a loss. For about 20 minutes I have no idea what to do.
So as I think about this, I figure that the only thing that changed was the new injector. So, with little hope I figured that I would just put the old one back and see if it hammers badly with that one, knowing that it couldn't be that and I am truly going to take a big hit on this one. So I pull the new injector, set the old one back in and tighten everything up. I say a small prayer, hit the glow plugs for 30 seconds, give her some throttle and hit the starter. I wince as she bangs back to life, skipping a little as I have just bled the system again. Then she takes off. I hold my breath as she comes up to speed, WITH NO KNOCKING! It's a damn miracle! I hold my breath for another 10 minutes and then start to relax just a bit. I throttle her up after 15 minutes and she is just running along happy as can be and the knock is nowhere to be heard. I sat there and watched her run for and hour and 30 minutes waiting for the knock to come back. I let her idle and ran her up to full throttle and she sounds just like she always has. Hope comes back and I say a small prayer of thanks.
Now, what just happened? Are injectors "blessed" to be in a specific cylinder? Did I get a bad injector? Is my motor happy with an injector leak and doesn't want to live without it? I am at a total loss, and am probably too scared to try to fix this stupid leak. Any ideas on what happened would be appreciated, and ideas on how to fix the leak would be appreciated also.
I have an 1982 Oday 28 with a universal 5411 diesel. In 2007 I swapped out the motor with a rebuilt 5411 as I didn't want to change stringers or re-engineer the powertrain setup. The motor went in with no problem and it has been running well since then. I have changed the oil every year, and the fuel filters every 2 years. Last year I noticed that the water pump was leaking and the injector on the back cylinder was leaking also. So I planned to fix these 2 issues this spring.
Last weekend I took out the brand new Oberdorfer pump and all the fuel filters. I swapped out the pump and changed the filters. Bled the fuel system and she started up with no issues. I had also replaced the fuel return line as I thought that maybe that was the leak in the back injector. I ran the motor for about an hour, and the pump did fine and she sounded normal.However, the back injector was still leaking and the fuel was smoking off the back of the motor. So I started to look at getting the injectors serviced. In my research I found an article that showed the "5411" is really a Z500 Kabota motor, and the injectors are readily available and $44.00 plus shipping. Seemed like a great deal to me, so I ordered one. It got here yesterday and it looks exactly like the ones I have now. I measured and checked and it seems to be a perfect fit. So now I'm excited to get this project off the list.
At the boat I pull the old injector, install the new one and bleed the system. I make sure everything is tight and kick up the throttle and hit the glow plugs and fire it up. She stumbles for a second or two and then takes off! Runs smoothly and responds to the throttle just fine. I check to make sure I have water out the exhaust and I do. So I jump in and grab my spotlight to look for leaks and make sure everything is holding together. As I am looking at the back injector (it's not leaking!) there is suddenly a huge "WHACK" and then the motor starts knocking like it's coming apart. My heart tries to jump out of my chest and I pee my pants right there. In a huge panic I jump for the throttle and shut it down as fast as I can. It knocks badly all the way down until it stops.
I sit there for a minute, feeling my sailing season slipping away from me. I cannot fathom what is in store for me. My engine compartment seems like a deep dark hole that has just devoured my excitement for spring. So I guess I might as well check and see what was out of whack. I check the temperature gauge and it's sitting at 135 degrees just like it always does. I check the oil dipstick. Plenty of oil and I check it closely for metal. None. Check for water in the oil. None. I grab the belt and try to pull the motor over. It moves and I can push it through both the compression cycles. I am at a loss. For about 20 minutes I have no idea what to do.
So as I think about this, I figure that the only thing that changed was the new injector. So, with little hope I figured that I would just put the old one back and see if it hammers badly with that one, knowing that it couldn't be that and I am truly going to take a big hit on this one. So I pull the new injector, set the old one back in and tighten everything up. I say a small prayer, hit the glow plugs for 30 seconds, give her some throttle and hit the starter. I wince as she bangs back to life, skipping a little as I have just bled the system again. Then she takes off. I hold my breath as she comes up to speed, WITH NO KNOCKING! It's a damn miracle! I hold my breath for another 10 minutes and then start to relax just a bit. I throttle her up after 15 minutes and she is just running along happy as can be and the knock is nowhere to be heard. I sat there and watched her run for and hour and 30 minutes waiting for the knock to come back. I let her idle and ran her up to full throttle and she sounds just like she always has. Hope comes back and I say a small prayer of thanks.
Now, what just happened? Are injectors "blessed" to be in a specific cylinder? Did I get a bad injector? Is my motor happy with an injector leak and doesn't want to live without it? I am at a total loss, and am probably too scared to try to fix this stupid leak. Any ideas on what happened would be appreciated, and ideas on how to fix the leak would be appreciated also.