White smoke from seawater outlet

[crieders]

engine running fine at 160 or so says the temp gauge. water coming into raw water filter and out to engine again, impeller pump working, water coming out of outlet in back of boat...so why white smoke? Thanks for any suggestions or thoughts.

[Ron Hill]

Cliff : Is it smoke or steam???  Watch how it dissipates!!   Did you get a blast of hi humidity and cooler air???

Steam or water vapor will rise and clear fairly rapidly!!  Smoke tends to stay closer to the water and takes longer to dilute.

A few thoughts

[Jon W]

Cliff, Per Ron's response, make sure you have steam and not something else. If it is steam, I had the exact same situation recently. After motoring for about 1 hour at 1800 rpm, steam would begin to appear from the raw water exhaust. Engine coolant temperature was fine. I have a 1987, with M25XP, 1/2" seacock for water inlet, and 5/8" hoses.

There was water exiting the discharge, but not enough water to cool the exhaust properly so the water turned to steam.

Check the thru hull is not clogged, the strainer is clean, and you have all the blades on the impeller.

Check that your hoses and HX are not clogged.

I changed to the Oberdorfer brand impeller. I found the blue Globe impellers didn't deliver as much flow.

Check that the injection nipple on the exhaust riser after the vented loop is not clogged. The ID should be around 7/16" to 1/2", but at least 3/8".

I changed my raw water pump from Oberdorfer N202M-15 to a N202M-16. In my opinion, and now experience, the -15 is too small for a M25XP.

Each of the steps improved water flow, and I no longer have any steam.

Hope this helps.

[Ron Hill]

Cliff : Jon made a good call!!  One of the things that C34 owners usually fail to check is the inside of the raw water face plate. The wear groves will hinder the pumps ability to move water - not a good seal!!!!

Check Jon's suggestions and your face plate before you purchase anything new!!

A few thoughts

[crieders]

i have an oberdorfer pump
i checked the impeller before I put the boat in
i did replace the strainer with a Vetus, as someone did on this page.

[Ron Hill]

Cliff : The question still remains - Steam or Smoke???

A thought

[Jon W]

Which Oberdorfer? A -15 with its' 3/8" NPT ports will barely work.

Check the ID of the hoses to and from your HX are not clooged. Remove one of the end caps on your HX. If it looks like this photo it's time to clean it, and may be the source of your problem.

Check the ID of the injection nipple on the elbow of the exhaust riser with a drill bit. Be very careful not to drop the drill bit into the hose/muffler. If you can't stick at least a 3/8" drill bit in there easily, the ID needs to be opened up to let more water through.

[scgunner]

Jon,

When it looks like that you can soak it in vinegar overnight then use pipe cleaners to open it up.