White Engine Smoke

[Daddyo]

As some of you may know, in the spring of 2013 when I was moving our DeFever 48 with twin Lehman 120s from Marathon to Maine I noticed an increase of white smoke in the exhaust. The boat had seen little movement for a couple of months in the keys. Immediately after getting underway I noticed the smoke. On day two I filled two of the tanks with fresh fuel from a known supplier. There were minor changes each day with humidity being determined to be of major influence. We all know that usually white smoke means steam, ie water in the fuel. This didn't seem likely given the quality of the supplier. After getting fuel several additional times the smoke increased. When underway a few days ago I had two shut downs from overheating. After much effort to find the problem by removing the cooling system and bench checking it I could not find the smoking gun, until I looked inside the seastrainer (not an easy thing when underway). The seacock was full of mussels. The steam was from a lack of adequate waterflow.

 

[Capt.Bill11]

Glad you found the problem. But for future reference, white exhaust smoke does not mean you have water in your fuel. It usually means incomplete or improper combustion. Brought about by things like, incorrect fuel injection timing, defective fuel injectors, low cylinder compression. It can also happen if you get water leaking into a cylinder head.

Where as getting water in your fuel usually causes an engine to shut down or damages injectors, injector tips and pumps.

 

[LaBomba]

Thanks Mark, good find and cheap fix. Got to like it! If I remember right you put a lot of Seafoam in the fuel tanks at the time with little improvement.

 

[motion30]

My 120 always had a little white smoke,' water temp was within spec and it ran well. I always contributed it to the water lift muffler

 

[bayview]

As Bill said steam has nothing to do with fuel and everything to do with inadequate raw water flow.
Check the exhaust hoses to make sure they weren't burned due to the restricted water flow.
On many boats reduced water flow will be apparent from a louder sound from exhaust.

 

[Ski in NC]

One quick check can save a lot of grief later in a cruise:

Once you get up to your normal cruise power setting, check the temp of the wet exhaust. You can do this a couple of ways.

If you have a swim platform, stick your hand in the exhaust flow, the water spilling out should be around 20 to 40F above sea temp, not hot enough to be unpleasant to the hand. Too hot to hold your hand in it, and not enough sea water flow. A restriction somewhere. Don't fall off the boat!!!

If no swim platform, in the ER check temp of water being injected into exhaust mixer. Should be cool enough to comfortably touch. Same with the rubber exhaust hoses, check the bottom (water is there more than the top, top will be hotter).

Some engines seem to run with marginal amounts of sea water flow even with everything good, so this check varies with different engines. The point is to detect when things are different (hotter).

Usually once at cruise, things stay stable. Best to check right at power up, then should have confidence it will stay that way.

On my Cummins, I can see the water spill out the tailpipe and have run enough to know what is normal.

If you see steam, that means exhaust may be hotter than normal. Can also mean atmospheric conditions are such that fog is near forming and engine can be normal.

 

[Captain K]

Had a very similar experience with my FL 120's. What I thought was white smoke was steam. The last thing I suspected was inadequate water flow as I had replaced impellers from on-board stores, and cleaned strainers on both engines only a couple of days earlier. Also curious was the fact that my engine temperature gauge showed only slightly warmer than normal. Shut down the port engine mid-way in a 22-hour crossing of the Gulf of Mexico to check oil. On start-up the overheat alarm sounded. Shut the engine down immediately, checked the "new" impeller. Found it had only one or two blades left. Replaced impeller with a recently purchased one. All was well thereafter. "Smoke," i.e. steam no longer visible. Learned not to trust new looking impellers I found in stores. Lord knows how long they'd been aboard the boat, as they were there when I purchased it.

 

[Ski in NC]

Yep, not good to trust old impellers. They age even in the box. I put a new one in every few years and keep the old ones as spares. The new ones I put in come right from the supplier, hopefully they are not that old, but who knows!!

 

[Billylll]

I assume you recovered the missing splines from the old impeller?
Bill

 

[Captain K]

BillyIII...yes.

 

[Billylll]

BillyIII...yes.

I thought so and didn't mean to imply you didn't know what you are doing. However I'm sure many newbies read these threads so I wanted to make sure what we consider to be basic is covered.
Thanks,
Bill

 

[Capthead]

I had a similar problem on my boat. I was crossing the channel to Catalina and the engine sound changed, it got louder and more popping. I turned around to look and white steam was barely visible at all, glanced at my temp gauge and it was rising fast.

I ran down to the Saloon and cut the engine off. Starboard of course and the raw water pump is on the far side of the engine meaning laying over a hot engine while underway and checking the pump. When I got to the pump I could see the connector had come lose. I have Dagenham Ford Lehmans and the drive is aft on that engine coming off the center mounted IP. I'm not sure the name of that drive but it has a center doughnut with cut out's in it. The drive that slides on the raw water pump's set screw wasn't there. Somehow it came lose and spun off.

Fortunately, I carry spares and replaced it. Once I was able to spin the pump, align the pieces and replace the set screw, I was back underway.

 

[SteveH]

Exhaust Temp Warning

Could save my bacon some day. Also installed on gen-set.

 

[Captain K]

BillyIII...excellent and useful idea.

 

[Billylll]

Steve H where did you purchase the exhaust temperature unit pictured? Who makes the unit? Thanks,
Bill

 

[Victoriana]

Had the same issue with steam and our lehman. We didn't notice any temperature difference or water flow decrease, but it was there and was really there at 2000rpm. Strainer was clear, impeller was good too. We were almost to the point of inspecting the heat exchanger (probably should have anyway) and possibly pulling off the exhaust riser. We lived with it for awhile and then finally upon a haul out for bottom new paint we discovered the hidden issue. The engine water thru-haul had a huge clump of sea growth covering it. I was amazed after seeing it how the engine temperature never increased. As soon as the boat was cruising again there was no steam.

 

[SteveH]

Exhaust Temp Warning

For the main engine I installed an Aqualarm system. Exhaust, Engine Monitors : AQUALARM, Warning Systems For Land And Sea I just added repeater lights and alarm from Radio Shack to the fly bridge. System powered though start bank battery switch. Total cost about $90.00

For the gen-set I got smart and purchased on Ebay a White-Rodgers snap disc (thermocouple), close on rise 180ºF, open on decline 160ºF. Attached it around the exhaust elbow with a SS hose clamp. At Radio Shack I purchased two LED lights and a piezo alarm. System powered through gen-set start switch. Tested everything with a heat gun and seems to works. Total cost about $20.00

SteveH

 

[markpierce]

How soon should I expect smoke (from a three-year-old John Deere 4045)? I've got 350 hours on the engine and the only visual/aural thing coming out the exhaust port is water and the sweet rumbling sound of a diesel engine.

 

[bayview]

with proper maintenance, never

 

[Billylll]

How soon should I expect smoke (from a three-year-old John Deere 4045)? I've got 350 hours on the engine and the only visual/aural thing coming out the exhaust port is water and the sweet rumbling sound of a diesel engine.

That's a loaded question. As someone posted if maintained probably not in your or my lifetime..........
Bill

 

[Daddyo]

Never unless something goes wrong BTW the Lehman brothers with over 5400hrs on the clock didn't smoke before nor do they anymore

 

[Daddyo]

Thanks Mark, good find and cheap fix. Got to like it! If I remember right you put a lot of Seafoam in the fuel tanks at the time with little improvement.

I did. I think Seafoam is great but it won't kill mussels in your strainer