FL 120 smoking on start up

In the last few days, I noticed my engine is smoking a lot when I start it. It always did a bit of white smoke as any old diesel but now it looks like it's trying to tell me something. Looks to me like the smoke is kinda blue-ish so I'm assuming it's oil related. Didn't have a good chance to investigate yet.

I know there is probably a ton of threads on this subject. If you could just point me in the right direction that would be appreciated.

The old joke, which is actually true-ish, is that if an FL120 doesn't smoke on startup, it's got a problem. This is true of most British engines, diesel or petrol, of that era. What happens is that oil that's left in the rocker box after shutdown gradually seeps its way down into the cylinders past the valve stem seals, which usually wore out about about 15 minutes after the engine was manufactured, and sits there.

When you start up, the combustion in the cylinders also burns the lube oil off and you have blue smoke out the exhaust. Absolutely 100 percent normal unless...... the blue smoke doesn't go away after a minute or two as the leakdown oil is burned off. If it persists even when the engine is up to temperarture, then there is a problem that eventually will have to be dealt with.

We have two 1973 vintage FL120s in our boat, and like my 1973 Land Rover, they fart out some blue smoke on startup. But this smoke is virtually gone within a minute. What we have never seen in 17 years of running this particular boat--- and one of us goes to the stern on every engine srtartup to watch the exhaust and signal to the person at the helm that the water flows are normal-- is white smoke at startup. Once the engines get up to temperature we'll get some steam out the exhaust during the winter but that's normal as the exhaust heats up the exiting cooling water in a cold air environment.

I agree w Marin, and to add Diesels are heat engines and when started the engine is too cold to completely burn the fuel injected.

The older injection system has no regulation to control the mixture unlike the HPCR engines with electric injectors. Until the engine warms up to fully burn the fuel it will pump a bit of unburned and partially burned fuel out the exhaust (very light oil sheen possible in the discharge water) and a bit of dark smoke (incomplete combustion) from both lube. oil and fuel.

Should go away soon after startup with no sheen and unless under a load no real smoke, steam is possible under the right temperature conditions or if running very hot.

How is oil consumption?
When were the injectors last serviced?
Does the smoke go away?
Is the oil level correct?
Is there a sheen of oil/fuel in the exhaust water?
How does it start?
Any changes to the way it run?

Totally understand that. I'm just a bit worried now because it looks like it's a lot more than it used to be. But once I get underway it's fine. There is no smoke whatsoever apart from the normal exhaust fumes.

SCOTTEDAVIS said:

How is oil consumption?
When were the injectors last serviced?
Does the smoke go away?
Is the oil level correct?
Is there a sheen of oil/fuel in the exhaust water?
How does it start?
Any changes to the way it run?

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Great questions to start troubleshooting.

Oil consumption is minimal. I will add a few drops every other week. Note that this is from before this issue. It will be interesting to see if it changes in the next few days/weeks.
Never serviced the injectors.
Oil level is where it's always been.
I'll have to check for the sheen in the exhaust water.
It starts like a champ. Always has. I push the button and it turns for a second before starting.
I haven't seen any difference to the way it runs for now. I only went for 2 short rides over the weekend (about 1 hour each).

Thanks for the help.

Don't forget that the sheen on the water is unburned fuel, not oil, and it's totally normal for this kind of old-generation diesel. Until the combustion cambers get up to temperature not all the injected fue is being burned so it goes out the exhaust and forms the sheen behind the boat. This will be more obvious and greater in cold weather when the engines are colder at startup.

It may be that the slight increase of startup smoke you're seeing is simply an indication that one or more valve stem seals have worn out a little more. Personally, if everything else is normal--- oil consumption, engine starts promptly, smoke goes away after warmup, engine idles and runs at higher rpm smoothly I wouldn't worry about it.

How many hours since the injectors have been checked/serviced? One book I have says 4-5000 hrs for the FL SP135. My generator guy says check at 1200 hours. If the tips are warn?

I never had them checked or serviced. Had the boat for 6 years and not sure about PO. I guess that's something I will have to put on my to-do list.

I'm not a Lehman guy, but given the age and injectors never serviced, I would think sending them in to get tested would be a good thing... After that if they checkout and everything else is ok, then I agree with Marin on not worrying about it.

A good rule of thumb I use is to see if the smoke comes back at hot idle, after taking off a load. If it burns clean then, and burns clean under load, no worries. If smoke comes back at hot idle, then time to investigate.

It seems on certain days, they just feel like being smokey.

Ski in NC said:

It seems on certain days, they just feel like being smokey.

Click to expand...

They're British. They're not only British, they're old British. The joke among people who own things like Series Land Rovers and old MGs and Austin Healey's and whatnot is that they use what we call the total-loss lubrication system. This is an absolutely brilliant, albeit messy, way to lubricate an engine. The idea is this---

The engine is designed to leak oil. Maybe not when it's brand new, but that's simply because the seals and gaskets haven't reached the right condition yet. Once they have, the engines leak like sieves. Which means you as the operator have to keep pouring new oil in. Which means the oil in the engine is constantly being renewed. Which is very, very good for the engine if not for your driveway (or bilge).

The Ford Dorset diesel, the base engiine for the FL120, is from this era. Ironically the total-loss system isn't working on the engines in our boat which, other than the ubiquitous gasket leak from one of the lift pumps which we finally got around to dealing with the other year, don't leak any oil at all.

I attribute this to the fairly low number of hours on the engines (about 3,000) and the possibility that whoever assembled the engine in Dorset, England back in 1973 screwed up and used the wrong kinds of gaskets and seals. We bought the boat in 1998 and to date the oil consumption of both engines has remained the same-- less than one quart every 100-150 hours which is our oil change interval.

But we continue to hope that the day will arrive when our two Lehmans begin leaking properly so we can finally start enjoying the lubrication benefits of the total-loss system.

With that system you never need to change oil, only filters!!!
The oil is constantly being changed!

Ted

Mine weeps a bit around the valve cover, I could replace the gasket but why, I like giving Henry (it's a Ford after all) a rubdown with a rag every 25 30 hours or so.

4800+- hours, I sent the injectors and the injector rack off for overhaul last year and the difference was simply amazing.

Ford/Sabre 120 the FL120 done right.

You should see the smoke on Sunday morning in Roche Harbour when 100 or so Lehmans all start up at the same time at the end of GB Rendezvous. Makes you feel proud.

Marin is right about the smoke and the fuel on the water. When you have to worry is if it smokes at normal operating temperature. Then you only have about a dozen years left before an overhaul.

I did the injectors on my Lehman and the result was that it seemed to put somewhat less fuel in the water and seemed to idle a bit better, can't remember if it was more efficient (needing less fuel for a given speed) but I doubt it. Even before I overhauled the injectors you could probably start it with a pull cord!

Also, as Marin did, replacing the gasket on your lift pump will cure 95% of your oil leaks. It seems to get everywhere and it is often mistaken for valve cover leaks.

Unless you overheat the old Clamcrusher, it's healthy.