I have a 1998 Hunter 376. Never had any problems with the engine the past five years, but I cranked it up a few days ago and no salt water is being circulated and coming out. I replaced the impeller and water is definitely not clogged coming into the boat. Anybody know what the problem might be?
Sea water cooling water Not coming out of the exhaust
- Thread starter 1998Hunter376
- Start date
If you confirmed that water is getting to the water pump, and you have a good impeller, could it be that the water injection into the exhaust elbow is plugged?
You don’t mention what engine you have, so just guessing. The exhaust elbow on the 2GM20F is known to plug up. Usually the blockage affects the engine performance ( exhaust back pressure), but it could block off the water injection I suppose.
You could try pulling the hose off the HX exit and see if water comes out when the engine is running.
Muffler plugged up? if that was the case, you would not get any exhaust out the pipe...so probably not the issue.
If it was me, I would start at the thru hull and check each step to see where things are plugged up....
- thru hull valve
- strainer
- hose to water pump
- water pump / impeller
- HX
- exhaust elbow
- water-lift muffler
- hose to exhaust out,et
Greg
You don’t mention what engine you have, so just guessing. The exhaust elbow on the 2GM20F is known to plug up. Usually the blockage affects the engine performance ( exhaust back pressure), but it could block off the water injection I suppose.
You could try pulling the hose off the HX exit and see if water comes out when the engine is running.
Muffler plugged up? if that was the case, you would not get any exhaust out the pipe...so probably not the issue.
If it was me, I would start at the thru hull and check each step to see where things are plugged up....
- thru hull valve
- strainer
- hose to water pump
- water pump / impeller
- HX
- exhaust elbow
- water-lift muffler
- hose to exhaust out,et
Greg
Sorry I didn’t mention but it is a Yanmar model # 3JH2E... Not sure if that will change your answer but if so, I would appreciate your insight. At any rate thank you for your response and all the detail.
While I was changing the impeller I should have turned on the engine just make sure the post was turning.... The impeller is so hard to get to....I shutter to think about having to take it apart again but I may have to go that route!
While I was changing the impeller I should have turned on the engine just make sure the post was turning.... The impeller is so hard to get to....I shutter to think about having to take it apart again but I may have to go that route!
I am not familiar with your engine, so I hope someone else chimes in.
is the water pump belt-driven?
You may be able to remove the discharge hose from the pump and crank the engine over to see if you are getting water that far. If that is easier than removing the cover plate. On my 2 GM20, that would be the case....the cover plate is on the back of the pump, so you have to remove the pump from the engine mount to service it.
Good luck.
Greg
is the water pump belt-driven?
You may be able to remove the discharge hose from the pump and crank the engine over to see if you are getting water that far. If that is easier than removing the cover plate. On my 2 GM20, that would be the case....the cover plate is on the back of the pump, so you have to remove the pump from the engine mount to service it.
Good luck.
Greg
It’s not uncommon for the impeller post to separate from the hub. New impellers are not immune from this problem. Only way to be certain is remove the cover and look while engine is cranking.
The easiest method would be to work backwards from where the sea water enters the mixing elbow. Disconnect the hose and get someone to crank the engine and see what comes out. Nothing ? keep going back towards the pump until you find the blockage.
Maybe you have one of these ....................
Maybe you have one of these ....................
You say water not clogged coming into boat. Does that mean when you remove the hose from the water pump that water is rushing in there? If it is not, you could have an air bubble. I get these and what I do is use my dingy foot pump and blow out the line from the water pump back through the thru hull. It clears the air and water freely flows again.
Starting with the easiest. My injection point into the exhaust elbow clogs usually every season. I pull the hose off and jam a screwdriver in the fitting. There are deposits that completely occlude the opening. A bit of reaming solves the problem.
What ................... you listen at the other end
or feel for the blast of air (gas) ?
And it needs to be applied every minute if it's foggy. Remember while under sail it's one long and two short. Once the blockage is cleared the boat will move faster. You'll hear the bubbles under the hull. And when your hand gets frostbite the line is clear.What ................... you listen at the other end
Sometimes the seals on the raw water pump wear and do not seal enough to prime. You can test this by removing the impeller shaft and coating it with oil. If it suddenly works, because the oil makes the seal, you know what the issue is. Whether you need to replace the seals or the pump is another question.
This sounds like how the engine of an old English sports car used to work
.I had an occurrence a few years back where we picked up a plastic ice bag on the water intake which acted as a flap valve. With the engine stopped we had water flow, but once the engine was running the suction of the pump would close the flap and block the water flow. Another off the wall possibility would be a faulty impeller where the rubber comes apart from the metal center part, looking fine but not spinning. Look for soft collapsed hoses or any blockage along the water route including the thermostat, mixing elbow and the muffler.
Thanks for all your input! Through trial and error I found it. It happened to be the mixing elbow clogged, relatively easy fix. Thanks for all your insight and advice. Made it much easier to get to the bottom of this!