Hunter 27 yanmar SB8. No water is coming out of the exhaust. Trying to troubleshoot, could use some help. New boat owner making my way down ICW to FL. Thank you!!
Yanmar SB8 no water out of exhaust
- Thread starter HOLLYALYSSA1288
- Start date
Is your water pump functioning? Did the engine overheat? Is the alternator working?
Welcome to the forum!
Welcome to the forum!
Simple things first.
Is the sea cock open?
Is the raw water filter clean?
Is the through hull clean, not filled with barnacles etc or weeds and grass?
When was the the water pump impeller last serviced/replaced?
Is the sea cock open?
Is the raw water filter clean?
Is the through hull clean, not filled with barnacles etc or weeds and grass?
When was the the water pump impeller last serviced/replaced?
Hi Holly
Here is a simplified diagram of your raw water cooling system.
Starting from water in you have the valve.
This could be closed.
Blocked with marine growth or waste like a plastic bag.
Strainer. This could be blocked and just needs a clean. It takes a big load to block a good strainer.
Pump. this could have a slipping belt (you should hear the squeal)
A broken or jumped off belt. (easily noticed)
A damaged or worn impeller. ( this like a rubber internal propeller)
Disconnect the hose at X and turn over the engine.
No water?
Disconnect at points leading back to valve.
gary
Here is a simplified diagram of your raw water cooling system.
Starting from water in you have the valve.
This could be closed.
Blocked with marine growth or waste like a plastic bag.
Strainer. This could be blocked and just needs a clean. It takes a big load to block a good strainer.
Pump. this could have a slipping belt (you should hear the squeal)
A broken or jumped off belt. (easily noticed)
A damaged or worn impeller. ( this like a rubber internal propeller)
No water?
Disconnect at points leading back to valve.
gary
Last edited:
Is there a small fitting on the mixing elbow where the water is injected into the exhaust? Mine had a small bronze elbow that would clog up with salt crystals. I would pull the hose and ream out the fitting with a small screwdriver. Sometimes I needed to remove the fitting to get to both sides of the elbow. I finally replaced it with a straight fitting. It was much easier to clean out. While the hose is off, crank the engine. Lots of water should come out. If not, I'd take my hose off the input side of the strainer and put my air horn on it. A couple of honks would clear the line back to the through hull. You'll hear the bubbles under the boat. If that still doesn't result in water flow then as suggested above check the strainer basket and finally the raw water pump.
it would help to know the following : (I note your 1st email was sent at 2:22 am)
were you motoring w/ engine on when you 1st noticed no water coming from exhaust? for how long?
how soon after you noticed no water out of the exhaust did you shut down the engine ?
did the engine overheat alarm ever sound ? (on some Yan panels the overheat alarm tests itself when you turn the key to ON before starting the diesel)
how long after alarm sounded did you shut down the engine ?
do you have a spare water pump impeller for this engine , and either some pliers or a jabsco impeller puller ?
last question --what's the harbor closest to you with a diesel mechanic?
were you motoring w/ engine on when you 1st noticed no water coming from exhaust? for how long?
how soon after you noticed no water out of the exhaust did you shut down the engine ?
did the engine overheat alarm ever sound ? (on some Yan panels the overheat alarm tests itself when you turn the key to ON before starting the diesel)
how long after alarm sounded did you shut down the engine ?
do you have a spare water pump impeller for this engine , and either some pliers or a jabsco impeller puller ?
last question --what's the harbor closest to you with a diesel mechanic?
Thank you all! Worked on the engine yesterday and got it sorted out (the elbow was blocked up with debris). Appreciate the feedback, it was super helpful 