Diesel Fuel Leak on Yanmar 3JH4E

[sailoysterbay]

I have a slight fuel leak in the top of my Yanmar 3JH4E near the injectors. This is a on a 2009 Catalina 375 with just under 900 hours. Trying to pinpoint the leak and resolve it. Could be the injectors, the return lines or hose clamps. Any other suggestions or ideas welcome.

[S/V Illusion]

Could be from each of those points. Should be easy to pinpoint if you start with cleaning the engine and then observe.

Crush washers aren’t intended to be reused.

[skipperpete]

The leakoff line tee has to be contestant #1, it could be as simple as a slightly loose hose clamp and there’s a vague possibility that the return to tank pressure is too high. Those little injector tee pieces are very fragile and to the best of my knowledge, not replaceable.
A leak from the hp union should be fairly obvious and a leak from the joint between the nozzle and the nozzle body would be highly unlikely..... but still a hidden contender.

[Ballsnall]

Degrease thoroughly and dry, then dust it with a dry white powder to show the leaks. I find dye penetrant developer spray ideal for this but you could try crushed chalk or maybe flour etc.
It is most likely the return line hose so I would just replace that anyway just to eliminate that first.

[sailoysterbay]

First I want to thank everyone for their suggestions.
I replaced the two suspect fuel return lines and the end cap with all new clamps.
When I attempted to tighten the hose clamps on the adjacent fuel line back to the tank via the filter, the clamps wouldn't tighten.
Alas, the clamps were stripped. I replaced the stripped clamps with the clamps I removed from the other return lines and ran the engine.
Since the boat was already hauled for the winter, I ran a fresh water hose to the seawater intake to cool the engine.
I did this two days in a row before winterizing the seawater intake with antifreeze.
I checked the engine for any fuel seepage three days in a row and so far it's all good.
Apparently the previously owner or mechanic overtightened and stripped the clamps.
It’s possible that the fuel was leaking due to the stripped clamps and tracing down the other lines and dripping off.
If anything changes in the spring, I’ll let you know.