My 25xp taking up smoking.....

Sep 25, 2008
464
Catalina 30 MKIII Varuna Boat Club
Before I start a project that might not be on the right track....I thought it might be a good idea to ask if anyone has this problem.

My Universal 25xp with 1,375 hours, has just started to smoke just a bit more than I am used to and is just a bit noisier too.

I've already changed ALL filters with no improvement and I'm not burning any oil. (smoke is light grey and somewhat whispy).

Any suggestions before I start adjusting valves?

Thanks all.
 
Oct 29, 2005
2,366
Hunter Marine 326 303 Singapore
Cancer cure smoking. :D suggest you remove the mixing elbow to check for fouling.
Just last week I noted higher vibration and some smoke and black stain on transom.
Removed the mixing elbow to reveal >50% blockage!
Clean it and problem solved :) :) :)
 
Last edited:
Sep 25, 2008
464
Catalina 30 MKIII Varuna Boat Club
...worth a shot. Thanks.

Cancer clue smoking. :D suggest you remove the mixing elbow to check for fouling.
Just last week I noted higher vibration and some smoke and black stain on transom.
Removed the mixing elbow to reveal >50% blockage!
Clean it and problem solved :) :) :)
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
bottom fouling can also make the engine work harder and run slower resulting in smoke. How long since the bottom got a cleaning?
 

RoyS

.
Jun 3, 2012
1,742
Hunter 33 Steamboat Wharf, Hull, MA
Water in fuel will give you a white smoke also.
 
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Universals do NOT have the exhaust elbow issues that Yanmars do.

Two completely different animals.

You have an exhaust pipe from the manifold back to the water injection nipple. Yanmars have a factory built elbow which is prone to leakage between the gas and water. On the Universals, what is called the exhaust RISER tends to rarely get clogged but does fail catastrophically from rust at the nipple or other joints.

Check the bottom first, it most likely isn't your exhaust riser.
 
Sep 17, 2012
115
Morgan 383 Fairhaven, NY
White smoke is typically unburnt fuel. Adjusting the valves can't hurt, (if properly done). Good place to start for sure. Fuel timing has to be right, and valve lash affects that to a point.
My engine responded to valve adjustment by starting quicker and perhaps a reduction in smoke at start up.

But I'd be prepared for a injector rebuilds.
What do you have for your fuel filtration system?
 
Sep 25, 2008
464
Catalina 30 MKIII Varuna Boat Club
Primary and secondary fuel filters are new. My first thoughts were valve adjustment in the hope it was not injectors......which are expensive.
But, I guess it is a distinct possiblility.
Thank you for the reply.
White smoke is typically unburnt fuel. Adjusting the valves can't hurt, (if properly done). Good place to start for sure. Fuel timing has to be right, and valve lash affects that to a point.
My engine responded to valve adjustment by starting quicker and perhaps a reduction in smoke at start up.

But I'd be prepared for a injector rebuilds.
What do you have for your fuel filtration system?
 
Sep 25, 2008
464
Catalina 30 MKIII Varuna Boat Club
Thanks Stu. I only changed my riser in 2012 and do not want to attack it again. You saved me quite a bit of time and effort.

Universals do NOT have the exhaust elbow issues that Yanmars do.

Two completely different animals.

You have an exhaust pipe from the manifold back to the water injection nipple. Yanmars have a factory built elbow which is prone to leakage between the gas and water. On the Universals, what is called the exhaust RISER tends to rarely get clogged but does fail catastrophically from rust at the nipple or other joints.

Check the bottom first, it most likely isn't your exhaust riser.
 
Sep 25, 2008
464
Catalina 30 MKIII Varuna Boat Club
Thank you for the thought. My bottom is clean.....except for the usual slime accumulation. The smoke does however seem to increase under progressive loading.
bottom fouling can also make the engine work harder and run slower resulting in smoke. How long since the bottom got a cleaning?
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
8,020
Hunter 430 Waveland, MS
All good operating diesel engines "smoke white". We normally quench and reduce the smoke/smell/noise with ocean water in a Riser.

I have about the same hours on my Volvo Penta, but my "white smoke" varies in intensity when...

1) Starting up and cold engine.
2) Idle rpm ( My sea water quench direct drive to engine)
3) Long duration between engine starts (3+ weeks )
4) New addition of fuel additives for injector cleaning, antibacterial, or water emulsifiers. (these treatments are to release and burn fuel contamination"stuff" in the engine.)
5) Perhaps a change in a fuel supplier, doing an antibacterial/water treatment on his tank.

I assume your engine gauges are about same now as "before". Oil pressure low and coolant temperature high would show you engine changes.

You engine hours are "infant" to have a major mechanical problem

Does the engine require a "longer" starts?

Most sea water supply systems have a siphon breaker, high point vent or other named back flow preventer of sea water back flowing through the riser into the engine open exhaust valve when engine is down. Whew that was a mouth full, lol.

Trace your sea water flow path you will find the siphon breaker ( high loop of hose above boat water line).

There is a "check valve" that bleeds air in and no water out. That valve should be cleaned and line cleared 2 times a year. If not working, water will "drip.... drip" water in to riser, fill the exhaust and get into your engine.

Last trick...
Engine coolant, sometimes called fresh water side, should be checked for volume and clarity.
If it appears contaminated then it could be an indicator of other issues.

Note: about surface corroded risers... this is a good thing if you Zinc anode is ok. Cast steel parts should corrode but not excessively. Never clean the protective "rust" off of the interior of your riser.
Jim...
 
Sep 23, 2013
5
ODay DS Sharonville
First requisite for all Diesel engines is clean fuel with no water.

I say again water in fuel is bad. To get water out of the fuel use a good new filter. Drain water from the filter often.

The second is injectors in good condition. Water ruins injectors.

The third run engine in proper rpm range. Do not idle. Idling kills the modern Diesel Engine.

The fourth use a good fuel additive (Marvel Mystery Oil, Sta-bil, Gumout, Stanadyne, Techron, etc.) to keep top end in good condition. Carbon build up between the top on the cylinder and first ring causes smoke.

Fifth keep the lower end clean change the oil and filter. When the oil looks dirty it is.

Last water is bad. Keep fuel filter clean. Carry an extra fuel filter. When engine runs bad drain the water from filter and replace the filter.
 

JamesG161

SBO Weather and Forecasting Forum Jim & John
Feb 14, 2014
8,020
Hunter 430 Waveland, MS
Ralph...
Sorry I missed your comment about "progressive smoking".

Check your sea water pump. It may be a worn/hardened impeller. Not enough water to Quench exhaust.
Jim...

PS: a guy named Diesel invented an engine to run on "crap" fuel. Water dissolved in fuel will not damage a diesel engine. Sucking separated off bottom of fuel tank is bad. Thus, a good fuel/water separator will show you if water has separated from fuel.
 
Jun 8, 2004
96
Catalina 30 Seabrook Texas
If raw water is restricted, white smoke (water vapor) will occur and will increase under load. Temperature should also increase. I had excessive salt build up (90%) at the HX inlet from the raw water pump. At 1500 rpm there was no smoke and the temperature was fine, increase to 1800 rpm and it began to smoke and overheat. I found the salt build up after I had salt water backup into the engine at the raw water pump. Now I clean it out every 3 mos.
 

slaume

.
Feb 21, 2014
105
Cape Dory 30 C Noank
Universals do NOT have the exhaust elbow issues that Yanmars do.

Two completely different animals.

You have an exhaust pipe from the manifold back to the water injection nipple. Yanmars have a factory built elbow which is prone to leakage between the gas and water. On the Universals, what is called the exhaust RISER tends to rarely get clogged but does fail catastrophically from rust at the nipple or other joints.

Check the bottom first, it most likely isn't your exhaust riser.
The Universal engine on my boat has an exhaust elbow. I had smoke issues a few years ago that cleared up when I replaced the exhaust elbow. It also made starting easier, Steve.
 
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
The Universal engine on my boat has an exhaust elbow. I had smoke issues a few years ago that cleared up when I replaced the exhaust elbow. It also made starting easier, Steve.
Steve, some do because of the configuration of the engine and the exhaust systems. No Catalinas that I know of do, though.
 

Waybad

.
Nov 12, 2011
25
Skookum 34 34 Custom DesMoines
a bit of noise

Steve, some do because of the configuration of the engine and the exhaust systems. No Catalinas that I know of do, though.
A bit of noise and smoke, bleed injectors it only takes a bit of air in the system to do both.
Note dissolved water in fuel is not good for any diesel engine. You lose lubrication to the tight tolerances in the injector pump. Also if it turns to steam at the injector tip it can blow the tip, (if the tip is extremely hot) and bits and pieces need to go out a valve, If your lucky. Drain water often and use a good fuel filters and do not use additive that dissolve the water and run it threw the engine.
Additives that break it up and then your filter traps are the way to go.
later
Waybad
 
Oct 9, 2012
10
Oday 27 Fairhaven, MA
Sure way to eliminate the smoke...

After dealing with old engines that smoke, make a ton of noise and SMELL, I've decided to go electric. A complete re-fit can be expensive, but I found a company that is pretty reasonable. Changing out just the power head for my OMC saildrive. Electric motor with a controller that will compensate torque to accommodate my existing outdrive. I will NOT miss the smell of an engine, or the fuel, grease and oil associated with it.

I know it's not an immediate remedy, but it will definitely get rid of the white smoke!