Injector noise?

[Warby12]

Hi, I know I'm maybe taking a risk posting a question that may be covered a million times but I can't find an answer, and you guys are so clever

Perkins 4108 was running perfectly but we have swapped in a new Bowman heat exchanger and with other activities it hasn't been run for about 8 months. Got her going today and all was fine, ran for about 20 mins under power up to normal temp and the only issue was grey smoke. Oil pressure, temp fine. I did change and flush out the first filter as it was full of gunk.

Suddenly a pronounced banging/taping louder as power increased.
Could this be a blocked injector? Maybe air? If so how should I deal with it?
If not an injector.....?

[model 10]

Oh yeah, they can make noise. They have some internal parts that can be sticky. Air can be a problem, so let it out. If cracking the nuts doesn't help, use a screw driver to your ear on each one. If one of them can be stuck, you should think about having them all serviced.

[sartorst]

Sounds like a fouled or bad injector not spraying the fuel properly , with the engine running open each injector line one at a time and note the rpm decrease the one or more that have the least rpm drop is where you need to start looking for problems you may be able to use a cleaner or have to remove and clean or send out for repairs, whatever the case don't run the engine too long with this problem because the raw fuel will wash down the cylinder and could cause damage long term
The grey smoke is raw fuel that has not been burnt which would account for the knocking also

[Warby12]

Thanks guys

Would it be safe to run the engine for an hour or two with some injector cleaner added to the mix to see if sorts itself or should I stop fiddling and get the spanners out?

[DeepFrz]

First of all change the second filter even if it looks clean. You also may have sticky valves.

[sartorst]

All the wear adds up I would not won't run it that long if its banging as you said depending on the situation I would find out which one and clean it ,most of the time cleaners are more for maintenance than a fix

https://www.youtube.com/watch?v=qb6Y0RuQye8

[shakey doug]

Sounds like a sticking valve.

[Warby12]

:bigg rin: Noise has gone !!!

I thought I better not blow this engine up like my old Hilux and went to the marina mechanic. From my description he said "sounds like air, run for another 20mins and if it doesn't go away, he'd take a look".

I went back started it and the noise had gone I hope it was air, not a sticking valve. It would be strange for valve to be unstuck and then stick when the engine warmed up wouldn't it?
We only need a few more months from this engine. We need to relocate so I can take up a job and join my wife as a worker again. if it keeps playing up with a job we can look at other options but I'm growing attached to it.

Pretty exciting, we've had this boat for a year and a half and only been for a test sail and to the fuel dock. We have a boat again!

Of course there's a definite exhaust leak, boat stinks haha next job has arrived

Thanks all, very much appreciated