Kubota D1105 Engine Knock

[LAchlan Fisher]

Hey all, I installed this Kubota engine in my sailboat to make a sort of "DIY" inboard. I have run it a handful of times and now and this time while running it I am noticing that it makes a knocking sound at idle. Last year it ran out of coolant while running and shut down due to the overtemperature switch shutting it down. I used an infrared gun to check the temp and it was around 210-220 range which is hotter than I'd like. Last year I was running it off a separate 5 gallon can of clean new diesel and this year I am running it off the 100gal built-in tank that has some ancient diesel in it that I'm guessing is older than 6 years. That being said I have two new quality filters and a water separator.

My question is what is the knocking sound coming from? It goes away as soon as I increase the RPMs and only occurs during the idle. This engine has around 300hrs on it. Any ideas? Rod Knock?

Here's the link to the video:

You can hear the knocking at times :07 and:22-:24


Thanks!

 

[Nicksacco]

Hey all, I installed this Kubota engine in my sailboat to make a sort of "DIY" inboard. I have run it a handful of times and now and this time while running it I am noticing that it makes a knocking sound at idle. Last year it ran out of coolant while running and shut down due to the overtemperature switch shutting it down. I used an infrared gun to check the temp and it was around 210-220 range which is hotter than I'd like. Last year I was running it off a separate 5 gallon can of clean new diesel and this year I am running it off the 100gal built-in tank that has some ancient diesel in it that I'm guessing is older than 6 years. That being said I have two new quality filters and a water separator.

My question is what is the knocking sound coming from? It goes away as soon as I increase the RPMs and only occurs during the idle. This engine has around 300hrs on it. Any ideas? Rod Knock?

Here's the link to the video:

You can hear the knocking at times :07 and:22-:24


Thanks!

Hi

I listened to the sounds over and over and I can't draw a confident conclusion.
I had a couple of questions since it seemed intermittent.
1) does the sound go away when hot (is it only there when cold?)
2) Have you disconnected any spinning items such as water pump, alternator looking for a change?
3) I don't know much about boats, but is there a clutch or something in the bell housing for output shaft that could be loose?
4) Have you tried running on fresh diesel again?

Here are videos I found that might help you out.

 

[lugbolt]

what is your compression pressure for each cylinder?