Diesel smoke

[Chrisc]

As succinctly as I can:
The engine is a 3cyl Perkins Perama, either 24 or 27 hp depending on what paperwork you read. The hours are unknown but not too many judging from the condition and the engine is a little under propped. Our normal motoring is at 2000 rpm.
Recently we had to motor home for three and a half hours due to a lack of wind. There was a short steep sea right on the nose and the boat was pitching quite a bit. H28s are notorious for hobbyhorsing. The last half hour to our mooring was in flat estuarine waters. The estuary is very shallow and it was a hot day so I would guess that the estuary waters were 2 or 3 degrees warmer than the sea outside. On the mooring with the engine at idle, it began to produce an amount of light grey smoke. Apart from the smoke, all engine operating parameters were normal. I shut down and went home to sulk. Next morning we motored the boat for half an hour or so, and have run the engine on the mooring a few times subsequently with not the slightest trace of smoke from the exhaust - everything is as it should be.
Engines make me nervous and I am wondering what was going on here. My wife's take on this is that the engine thought it would take up smoking. Tried it, didn't like it, gave it up.
I don't think its that simple.

[irwin37]

May have been a sticking/dirty injector. If it dribbles instead of squirting a spray the fuel does not burn completely. Might have to have the injector checked if it happens again. not too big a deal.

White smoke occurs when raw diesel comes through the exhaust completely intact and unburned. Some causes of this include…

• Faulty or damaged injectors
• Incorrect injection timing (could be a worn timing gear or damaged crankshaft keyway).
• Low cylinder compression (eg caused by leaking or broken valves, piston ring sticking, cylinder and/or ring wear, or cylinder glaze)

When white smoke occurs at cold start, and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing.

[mub]

I agree with Irwin as that is the most likely thing.

There is a possibility that with the steep sea the prop became unloaded and the injector pump got "stuck" full open. In the estuary it might not have been noticeable.. but at idle.. it would have smoked lots.
Going through the start - advance sequence could have reset it.

I would consider having the injectors serviced. If your local shop is good they will tell you what state the injectors were in which will give you fix confidence.
Of course if they say there was no problem have them do the pump.

I payed 35 per injector and 300 for a pump rebuild this winter. That was on a Perkins prima.

Mub

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[westwinds]

Overheating? Check intake, screens, impeller, elbow, hoses
Heat exchanger. Is there good water flow out exhaust?

[Chrisc]

Thanks for the replies.
Ive got a bunch of those little plastic fuel line and injector tip protector thingies so I will take your collective advice and pull the injectors and get them serviced.

[irwin37]

Sounds good, I want to know were your getting the pump rebuilt, Im looking at 600 - 900 to have my 4108 injector pump done.

"I payed 35 per injector and 300 for a pump rebuild this winter. That was on a Perkins prima."