No water coming out

[John]

A few days ago I changed the impeller and the alternator belt on the Universal M35B engine on my boat. I checked to see if everything was okay, and it seemed to be - no leaks and I thought that I saw the raw water coming out. This evening I went to take the boat out and no raw water was coming out. I took the pump apart, and the impeller seemed to be fine. I took the hose off the heat exchanger - the hose that leads out the boat - and when the engine ran there was water pumping out the heat exchanger. I was thinking that that last hose is blocked, but there's one odd thing: When the engine runs, however, I can see that there is air coming out as I can see a depression in the water right under the water outlet.

My plan is to run a snake through that hose, but if that doesn't do the trick does anybody have any suggestions?

 

[SEMIJim]

Well, if you had a straight raw water cooled engine, I'd suggest perhaps the mixing elbow is clogged, but I don't know fresh water cooled systems as well.

Jim

 

[John]

I should add that I ran the motor for about 3-5 minutes (I think). Long enough for it to start to get warm.

In reply to Jim: I thought something might be clogged, but what's strange is that air seems to be coming out.

 

[eliems]

I changed my impellor last week but when I tightened the drive belt on the water pump I didn't notice it wasn't riding on it's drive pulley. Result ... no water coming out. Fortunately my wife noticed the error right away.

 

[John]

not belt

I changed my impellor last week but when I tightened the drive belt on the water pump I didn't notice it wasn't riding on it's drive pulley. Result ... no water coming out. Fortunately my wife noticed the error right away.

The belt is fine and, as I said, there is water coming out up through the heat exchange but not from there out of the boat.

 

[petersea]

if there is air coming out the exhaust then water is capable of running thru the hose. ( it may have a partial clog but some water will exit if air exits ) since u said water is coming out the engine with no problem then somewhere between the engine and exhaust outlet you have a water leak, did you check the muffller/water lift for leaks ?? check bilge for water ?

 

[RAD]

Also did you change the impeller cause it failed or routine maintenance if it failed and there were piece's did you find them all.....common mistake people make is not looking and the broken impeller piece finds it way into the HX or oil cooler downstream

 

[John]

routine

Also did you change the impeller cause it failed or routine maintenance if it failed and there were piece's did you find them all.....common mistake people make is not looking and the broken impeller piece finds it way into the HX or oil cooler downstream

I changed the impeller for routine maintenance.

 

[emilbec]

is water coming into the boat? Take the hose off the seacock and open it and see if water coming into the boat under pressure. Over the years I've had one or two experiences where a fish or barnacle got into and clogged the engine inlet. You can either clear with a "snake" down the water inlet or by diving on the boat.

 

[Maine Sail]

John,

The air is engine exhaust and is separate from the water. Check your intake seacock and hose for an obstruction and then move down the line..

 

[John]

intake

John,

The air is engine exhaust and is separate from the water. Check your intake seacock and hose for an obstruction and then move down the line..

I started at the intake into the raw water pump. there is water flowing through there into the pump. Then I took off the hose going to the heat exchange at the pump end. When the motor runs the water gushes out of the pump. Then I took off the hose going out the boat from the HX end. Again, when the motor runs there is water coming out there. Is it possible that there is some sort of air lock in the mixing elbow or something like that?

Question: I know that you're not supposed to crank the motor for more than about 20 or 30 seconds or you can get water into the engine somehow. What exactly causes this? Could it be something similar that is happening in my case?

 

[zeehag]

are your water strainer and water filter clean??? or has the filter filled with some thing??/ or is there a critter living in your intake thru hull????
if your riser is correct then shouldnt have incoming water into engine from cranking.......
do you have wet muffler?? is it actually working with water in it??
did you check for impeller failure in new impeller?? can happen,, as many have had experience with the center of impeller turning and the working rubber part standing still......... check it out to make sure -- gooodluck...

 

[rdowall]

You could have a faulty impeller or the key fell out as you installed the impeller. Suggestion: remove the coverplate on the pump and turn the engine over with the starter. Check to see if the impeller spins.

 

[John]

impeller &

are your water strainer and water filter clean??? or has the filter filled with some thing??/ or is there a critter living in your intake thru hull????
if your riser is correct then shouldnt have incoming water into engine from cranking.......
do you have wet muffler?? is it actually working with water in it??
did you check for impeller failure in new impeller?? can happen,, as many have had experience with the center of impeller turning and the working rubber part standing still......... check it out to make sure -- gooodluck...

I didn't check to see if the impeller is actually turning, but the fact that it pumps out water (as seen when I take off the hose) indicates that that's not the problem. Also, yes I checked the raw water strainer. It seems to me that the problem has to be somewhere from the heat exchanger to the outside of the boat, as water comes out of (the HX) when the hose is removed and the engine runs. No, I didn't check the muffler or anything past the HX. In fact, I've never done anything with those items and really don't know anything about how the mixing elbow works. Excuse my ignorance, but is that the same as the muffler? Can there be some sort of air lock in it? If so, what is the solution? (I was thinking of taking a hand pump and pumping water into the hose going to it. Any thoughts on that?)

 

[zeehag]

mixing elbow is different from water muffler--- mixing elbow could be problem, is a cast piece on the manifold. muffler is more toward the exit of the entire system. if mixing elbow is clogged-- sometimes it can be short term fixed by cleaning it out with muriatic acid..... goood luck. the mixing elbow can last only 5 yrs --sometimes longer sometimes shorter depending on use and such.....i was told by yanmar that item should be replaced every 5 yrs.......some have been cleaned after 7 and still in use-- see nice n easy--he did that last year or yr and half ago with good results.

 

[SEMIJim]

I think some of y'all are missing something:

I took the hose off the heat exchanger - the hose that leads out the boat - and when the engine ran there was water pumping out the heat exchanger.

Now, if I understand what he's saying, and if this system works like I suspect it does, that means that everything is good up to (probably) the mixing elbow, which is just prior to the water lift muffler. (The hose could be clogged, but that seems unlikely.)

That "air" he's seeing is exhaust gas. That's what actually forces water out of the water lift muffler--if there's any water in it.

Jim

 

[John]

Yes

I think some of y'all are missing something:
Now, if I understand what he's saying, and if this system works like I suspect it does, that means that everything is good up to (probably) the mixing elbow, which is just prior to the water lift muffler. (The hose could be clogged, but that seems unlikely.)

That "air" he's seeing is exhaust gas. That's what actually forces water out of the water lift muffler--if there's any water in it.

Jim

Yes, Jim seems to understand what I've done. I have plan "a", "b" and then "c". Plan "a" is to run a snake up that hose as far as it will go. I did this once before and it resolved the problem then. I was thinking of getting in a dinghy and running the snake up from outside the boat, too. Plan "b" is to use a hand pump to pump water through that hose. Plan "c" if all else fails is to... Well, actually, I don't have a plan "c", except to write back to this forum. Any thoughts on plan "b" or other suggestions?

 

[zeehag]

i would remove the mixing elbow and clean it out before putting a foreign object up into the system and possibly puncturing something sensitive.....

 

[John]

Incidentally, I should mention: I had left the water pump taken apart for 24 hours. (I inow that's not a good idea, but I got lazy and didn't want to bother putting it back together and taking it apart again.) I was wondering if during that time the water could have all drained out or in some other way it's possible for the muffler or the mixing elbow to have some sort of air lock.

 

[RAD]

The shaft key might be the problem....even though it pumps water it might be spinning without the key but not fast enough for the whole run