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Author Topic: Chasing m25xp smoke  (Read 146 times)

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Chasing m25xp smoke
« on: July 23, 2020, 04:37:32 PM »

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:

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


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  • "Positive Impact" 1984 C-30 #3573 trbsfk M-25
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Re: Chasing m25xp smoke
« Reply #1 on: July 23, 2020, 06:39:54 PM »

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
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


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Re: Chasing m25xp smoke
« Reply #2 on: July 24, 2020, 07:45:08 AM »


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


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Re: Chasing m25xp smoke
« Reply #3 on: July 24, 2020, 08:16:01 AM »

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

See you out on the water


Ron Hill

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Re: Chasing m25xp smoke
« Reply #4 on: July 25, 2020, 12:32:28 PM »

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

A thought
« Last Edit: July 25, 2020, 12:33:10 PM by Ron Hill »
Ron, Apache #788
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