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Capt Andy · 28-05-2023, 10:02

I replaced the black foam air/noise filter in my engine before going out yesterday. Sea condition was fairly bumpy going out but the engine ran fine w/o problems for a good hour before getting the sails up. Coming back when we powered up the engine it ran fine for about 10 min at 3000 rpm then I noticed periodic drop and recovery in rpm's and the engine sounding a little rough. I was suspecting some contamination in the fuel after the bumpy start. After 30 mins the engine was struggling more until, about 50 yrds from the slip and at the marina entrance the engine quite all together and wouldn't restart. Luckily we were able to float to a guest pier and tie up. After a tow into our slip I looked into the air intake there was no filter. Suspect it got pulled into the engine. Engine temp was steady at 160-170F, oil pressure was fine. How bad could this be? Fuel injectors fouled? Engine rebuild? Can anyone recommend a diesel mechanic in the Everett, WA area? Thanks!

capt jgw · 28-05-2023, 10:19

I'd start by taking the intake manifold off, hopefully you find the filter inside mostly intact and blocking the air flow. I don't know what would happen if it got sucked into the cylinders.

DougR · 28-05-2023, 10:37

As mentioned, could be that the filter blocked the inlet passages and the engine died from no air.

I have also experienced something similar on other engines where the foam filter got torn up and small pieces of the foam were hung up and able to hold the inlet valves just a little off the valve seat, causing a loss of compression and the engine quit running. I suppose it could also happen on an exhaust valve as well if a piece of foam made it thru the combustion chamber.

Picked the foam out with tweezers and no further problems.

Capt Andy · 28-05-2023, 11:12

Thanks for the replys. My mind goes to the worst case scenario. I'll pull the intake and see what I can see.

Capt Andy · 01-06-2023, 07:20

Well, I didn't kill the engine. I looked in the air intake and there was nothing there. No obstruction. Started up the engine and it ran like there was no problem. Ran it under load in the slip and it ran fine. Not even a cough. Still would like to know why it stalled. Anyone know a good diesel mechanic in the Everett, WA area?

Cheechako · 01-06-2023, 07:51

Well, it ingested the foam. Hopefully it didn't stick in an intake valve long and now it's cleared somehow. Or on top of a piston and burning up gradually. There should have been a perforated metal inside piece to restrain the foam, Was it put back together wrong? None of my boat diesels have ever had anything but metal in the intake. A "filter" is not necessary like a lawn mower or etc has because there is no dust to speak of really for a boat engine to ingest.