Chasing m25xp smoke

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sloopdog

So I'm all in my head about the amount of smoke or vapor that is coming out of my exhaust.  It doesn't happen until the boat is warmed up and under a load of about 2200+ rpm.  The video is once the engine is warmed up and I'm cruising along at about 2500rpm.  I've noticed this  before but am unsure if this is a normal amount and nothing to worry about as other m25 motors I've had did not smoke/water vapor.

Just looking for some group wisdom here in chasing this down!

Short video:  https://youtu.be/uBJAgaRxaeY

Boat Details:
1988 Catalina 34
Universal M25xp W/ approx 2000 hrs (I know history on engine going back to about 600 hrs)
10x15 prop
Bottom cleaned a couple months ago
New injectors
Recently adjusted valves
New kubota freshwater pump
Rebuilt Oberdorfer N202m
Filters changed religiously
currently running a Kubota 160 thermostat

1988 Catalina 34

KWKloeber

Would you classigy it

white smoke
darker smoke
water vapor
Whats the air temp and humidity (vs other times w/ no "smoke".)

Att that can be important in answrig the questions
]-k
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

scgunner

Sloopdog,

When motoring along I get the occasional wisp of steam, and I have been since I got the boat in 1988. I couldn't run the video but from the picture it looks like yours is about the same as mine. Unless it's billowing clouds of steam I wouldn't worry about it to much. The important things to keep an eye on are the temp gauge and your coolant level, if those things are normal you should be good.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

britinusa

If you run the engine at those rpm while at the dock, the exhaust will be easier to see and examine.

Ours runs clean, no smoke or steam, at 2000 rpm (max of 2100 rpm on ours) but if we rapidly change engine speed then we get dirty grot blowing out.


We replaced the injectors and tubes last year and had the injector pump rebuilt at the same time.

Paul
Paul & Peggy
1987 C34 Tall Rig Fin Keel - Hull # 463

See you out on the water

Engine:M25XP

Ron Hill

#4
Sloop : As Ken points out - the color of the smoke ? is the key!!

A thought
Ron, Apache #788

sloopdog

Extremely late followup here but I've moved the video over to Youtube so everyone should be able to easily view. 

https://youtu.be/uBJAgaRxaeY

To answer some of the questions posed:
        - I would classify as white but take a look at the video.
        -Water temperature is about 50 degrees always (San Juan Islands, WA).  It seems to be present at all ambient temperatures I've been in but video was probably 65F to 75F
        -Only happens under load once the motor is warmed up.  Is constant unless I'm under 2000 rpm.
        -With thermal gun the temp of my exhaust tubing at the thru hull is less than 100F.  Temp on Engine thermostat area is right about at 160 regardless of rpm. 


I appreciate any ideas or thoughts even if it's "don't worry about it and go sailing", which is partially why I haven't been able to follow up!
1988 Catalina 34

Ron Hill

Sloop : I looked at the video on U-tube and it looks like steam to me!!  I believe that it's the atmospherics and wouldn't worry about it.

Probably is happening on your auto, you just aren't looking backwards to see it!!

A thought
Ron, Apache #788

Stu Jackson

Quote from: sloopdog on September 01, 2020, 02:42:20 PM

I appreciate any ideas or thoughts even if it's "don't worry about it and go sailing", which is partially why I haven't been able to follow up!

OK, I'll bite:  "don't worry about it and go sailing"  :D

Really.  Why?  We've had our boat for 23 years, sailed 1998 to 2016 in San Francisco, sailed up here in 2016.  Never had that "stuff" come out the back "down there."  "Up here", it's NORMAL.  Not an issue.

Go have fun, no excuses now... 8)
Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

KWKloeber

Quote from: sloopdog on September 01, 2020, 02:42:20 PM


        - I would classify as white but take a look at the video.




I'd buy a color wheel!  That's not white smoke, it's water vapor   No issue.
Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

scgunner

Sloopdog,

If you're looking for a problem it's possible you could have a vane broken off from the impeller. A few years back I had a couple of vanes caught in the  cooling system, it caused it to steam a bit more than normal but the engine temp never changed. When I pulled the heat exchanger to clean and paint it I also tracked down the broken vanes and removed them. The thing is I knew they were in there but didn't bother with them until regular maintenance provided an opportunity. Since you don't know and your running normally I wouldn't worry about it.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

sloopdog

Ha I guess that's all the confirmation I needed to file it under don't worry about it.  I appreciate the responses!

in response to scgunner I did burn up an impeller last year but replaced and also rebuilt the entire pump.  I'm pretty sure I pulled all the vanes out of the elbow but there could be more in exchanger.  Regardless, I've pulled hoses downstream and I have plenty of flow through there. 

Thanks all for the input.
1988 Catalina 34

Ron Hill

Sloop : You might think about pulling the HX and opening it up; and see what "treasures" are inside like impeller blades and old chunks of Zinc!!   :shock:

A thought
Ron, Apache #788

scgunner

I'll second Ron, if it's been awhile you might think about pulling the HX to check, clean, flush, and repaint the unit, but I'd probably tie it into your next 100hr service. Also, I'd check that zinc regularly, if it goes away corrosion will attack your HX and that's an expensive replacement. I check mine once a month, but I may be a little paranoid.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273

sloopdog

Thanks I will get to the HX during the winter. It has been on my list but hasn't quite risen to the top yet. I know it's a new 3 inch version installed probably 4 years ago and hasn't been pulled since. I replace the zinc at least a couple times a season as I've also heard stories of how they corrode rather quickly and break off in there.
1988 Catalina 34

scgunner

Sloopdog,

Regarding that zinc, a lot depends on where you're at(even in the same marina)and who your neighbors are. I've been moved around in my marina and had numerous boats of all kinds as neighbors in the 30 or so years I've been there. One thing I've learned is based on those factors and probably others is there's noway to predict how long the zinc will last, sometimes the zinc will be gone in a month or two and sometimes the zinc has lasted well over a year. That's why I check mine once a month.
Kevin Quistberg                                                 Top Gun 1987 Mk 1 Hull #273