Heat exchanger

[gonesailing13]

Would a bad heat exchanger create any smoke problems ? Our boat has what I believe to be the original heat exchanger and was wondering if this would contribute to any smoking issues. Looking to replace it anyway so I know where I start from. BTW I’m talking about a white smoke issue.

 

[O C Diver]

Is it smoke or steam? Reduced flow can limit the amount of raw water getting to the exhaust elbow. You may have enough to keep the engine running at the correct temperature, but not enough to keep the water from turning to steam in the exhaust elbow.

Ted

 

[gonesailing13]

I’ll have to check this weekend if it’s smoke or steam. I do notice though that I have a little bit of a sheen on the water. Could the heat exchanger be the cause or maybe the elbow. ( this is all pretty new to me )

 

[O C Diver]

Ford Lehman?
How many hours on the engine?
Need to know if it's smoke or steam. When running, can you see lots of water out the exhaust, moderate amount, almost none? When was the last time you changed the raw water impeller?

Ted

 

[gonesailing13]

Ford Lehman 135, new raw water impeller, moderate amount of water coming out. As for the hours I’m not sure, the PO installed all new gauges so not clear on the hours.

 

[O C Diver]

You need to figure out if it's smoke or steam. May be as simple as cleaning the tubes in the heat exchanger. I would rather figure out what the problem is than keep changing parts until it's fixed, maybe.

Ted

 

[OldDan1943]

Get a diver out to clean the bottom and all clam shells. Could be restricted water flow.

 

[Pete Meisinger]

F.L.s dump a LOT of cooling water, even at idle. You don't say if the engine is running hotter than normal but it very well could be in which case you are looking at steam, not smoke.

People always say that F.L.s dump a bit of a sheen on the water. Not necessarily true. Mine used to, especially when docking after a run, the last two miles of which are at idle due to no wake zone coming up the river. Since I had the engine totally rebuilt, no more sheen on the water, and no more smoke.

pete

 

[C lectric]

Diesel smoke vs steam can be determined by the nose/eye test in many cases. Improperly burned diesel will have a strong smell, acrid and will 'grab' your nose and maybe cause eye watering. It also won't dissipate readily without a strong wind, often leaving a long trail as you travel..
Steam may look the same but there is usually minimal odour AND it will dissipate readily NOT leaving a long trail.

At certain times of the year steam can form as a natural byproduct of the water release by the combustion process. If that is all it is then once running and the engine heated up it should disappear.

If it continues or gets worse, is persistent, as the engine heats then you may have a cooling system problem.

THe guage may not show anything wrong, YET, as the heat exchanger can still get rid of the heat but it is losing it ability to do so.

I have added my tome below. Read it through for information at this point and see if it jogs any questions.

 

[Xsbank]

Happens every year as soon as the temperatures drop, the warm exhaust water makes vapour (not steam) and the dreaded smoke issue rears it's head. However, if you have never had your exchanger off, all bets are off. That's a periodic maintenance item.

 

[catalinajack]

How old are your exhaust elbows? They have a useful life. And, they are cheap and fairly easy to replace.

I’ll have to check this weekend if it’s smoke or steam. I do notice though that I have a little bit of a sheen on the water. Could the heat exchanger be the cause or maybe the elbow. ( this is all pretty new to me )

 

[kchace]

He said he has a FL135 which uses a Stainless Steel elbow (mixer) they have a much longer life than the cast iron models, but still should be checked periodically.


Ken

 

[catalinajack]

Missed that important fact. Sorry guys.

He said he has a FL135 which uses a Stainless Steel elbow (mixer) they have a much longer life than the cast iron models, but still should be checked periodically.


Ken

 

[gonesailing13]

Actually the boat has an cast iron elbow.

 

[kchace]

Actually the boat has an cast iron elbow.

Then its definitely something to check.

 

[OldDan1943]

Engine manufactures will quietly change the alloy of exhaust elbows w/o telling current owners'. Found that out with the exhaust elbow of my generator.

 

[SoWhat]

Is is an easy task to pull the front off the heat exchanger and check. Anything that gets past the raw water strainer will end up clogging the tubes. Maybe pieces of broken impeller vanes. It's worth a look.

My starboard engine smokes a little. Assuming it's rings but won't know for sure until I adjust the valves and eliminate that potential cause.

 

[AquilaCat]

In my case the smoke was from a wrong sized prop. The MarineMax charter CO installed a different size prop to get back on charter and adjusted the throttles to match. After purchase I spent may thousands on the engine before having a prop shop spec the props. No more smoke.

 

[PeterMcK]

Suggest you have a read of Tony's Tips -
https://www.sbmar.com/articles/what-is-white-smoke/

 

[jleonard]

If this were my boat, I would take off every heat exchanger and flush them out and inspect them. Rod them out f necessary, flush them out with Barnacle Buster, or CLR, or whatever.
Put new zincs in, paint them and reassemble. Change out the hoses if they are old and brittle.
ADC has all the parts you need and they ae cheap.
Flush out the old antifreeze and put in new.
Now you know everything is good.
Did I mention a new impeller as well? I should have.

 

[catalinajack]

So, what is the consensus? Are the DST 800/810s problematic or do they just require a bit of maintenance?