or so I thought-well, spent the weekend over around the Daytona area with no issues, ran fine.....we got back home on the trailer and I wanted to flush the salt, had planned on putting in the river but got back to late....so I grabbed the muffs, Keep in mind I have a 1/2 closed system and I also have two raw water pick ups: the foot and a thru hull. I turned off the thru hull, fired it up and looked to see that I had water coming from the back and was good so went about some other business in the cabin when I heard it start squealing- I was right by the key so I turned it off. I looked to make sure nothing had happened on the water supply side and was good so I fired it back up- looked underneath and no water flowing. Now, from the start of working on this pump, I have always been concerned that since it has two water pick ups and the thru hull looks like the largest supply source for water, did I just prove myself right, in a very painful way?
Ras, i tried to find an answer for you, but really didn't. what i did find was a couple of people saying the thru hull was to make sure you had enough water coming in at all times to keep everything cool . there was also several people with the same set up with out the ability to close a seacock as they did not have one. when you say you seen water coming out the back for how long did you observe it for?
Ras, the sensor where the raw water enters the power steering cooler is measuring water pressure, not temperature. There are three temperature sensors:
* one Engine Coolant Temperature (ECT) sensor measures the temperature of the closed-cycle coolant. This is what's shown on the gauge. The sensor is next to the thermostat.
* two Engine Manifold Coolant Temperature (EMCT) sensors measure the temperature of raw water exiting the port and stbd exhaust manifolds. Temperatures over 212 deg F will trigger an alarm and reduce power.
Have you tried disconnecting the pump output hose to verify that it's pumping?
JC- The motor ran for probably 2~3 mins- as soon as it started I looked to make sure the water was coming from it's exit, I went back to doing other things assuming either it's working or it's not! I have not pulled anything apart yet, the last time I went through this I pulled the intake hose off and put a hose in and it moved the water ok but that was only because I was force feeding it I suppose...and then rebuilt the pump and thought I had it solved. As far as not having a seacock for the thru hull, what would they do if they had a leak in the hose with no way turn it off? Good info on the sensors LaRea, that makes a lot of sense.....the only other thing I need to check is to make darn sure I have the sea **** on the thru hull all the way closed- I 'd suppose if it were not eventually the air would be easier to pull then the water and perhaps loose the suction on the water but I'm pretty sure it is. What happens to a new impeller that over heats? Would it de form to the point it would not keep suction? Certainly I need to find an explanation as to why it stopped pulling water to it, it's a pretty simple pump! A couple weeks ago I was on the river and got into some shallows and must of sucked up some mud as the pump screeched for just a couple of seconds and then cleared- ran it afterward and had no apparent over heat issues but as LaRea points out that only means the water exiting is less than 212 degrees. Also, my speedo is not working anymore so must of sucked up some gunk into where ever that goes through the foot, where is that by the way and could that be a factor in this?
The speedometer pitot tube is a separate inlet on the leading edge of the outdrive (not connected to cooling water circuit). It'll get clogged any time the drive touches a bit of mud.
If an impeller overheats from running dry, the ends of the vanes will turn to dust and it'll be unable to move water.
(A thru-hull with no seacock?! No boat-builder would sell a boat that way. Gotta be a user installation by somebody that doesn't know boats.)
I will verify the seacock was closed completely and if so, next stop is pulling that pump off again....I'm am concerned to do that and just have the problem again...if it was pumping water, what would have caused it to fail? I have good pressure, never moved the throttle. Would not seem likely that I could have pulled anything through the foot that would have caused a failure and I have a sea strainer for both the thru hull and the foot....so I'm puzzled how this would happen. I guess when it stop screeching then the damage is done, we'll see....
well, good news is I figured it out, bad news looks like I did it. The seacock was open 1/8 or so. Please don't ask. I'm guessing the water seen coming out was in the system, valve was open enough to suck air and not water and I'm guessing, almost hoping, burned the impeller as being the problem. I took the cover off my sea strainer and stuck a hose in there and no pumping going on. I am my worst enemy sometimes...
sorry to hear that Ras. that was where i was going with my previous question on how long you watched it for, trust me your not the only one ever to do that.
well, that makes me feel a little better, not much but a little! thanks for the kind words...I'm pretty sure that's what I did, a 35 buck repair which is getting off pretty cheap in the boat world so I won't be complaining- it's a mess here weather wise but hope to pull it off tonight after work and check it out...
there is no way that is near all the pieces.....water came out of the hose and I assume lot's of pieces but will be reading up on how to back flush the heat exchanger......
Well, it's pretty easy to clear the heat exchanger. Take off the end cap (one bolt, and pry it off with a screwdriver) and you'll see any pieces that made it that far. If any small pieces made it into the tubes, they should get flushed downstream when you repair the pump. Or you can take off both ends and go after it with compressed air or a hose nozzle.
Larea- doesn't the water go through the tubes? If I take the end caps off I'm into the coolant, not the raw water correct? I need to blow out those tubes to get to the little pieces??
The heat exchanger has tubes for both coolant and raw water. The end cap gives access to only the raw water inlet, not the coolant. It's a 10-minute operation to pop the cap off and clean out any debris.
I re ordered the whole "kit" as when the impeller went, the metal became exposed and looks like it grooved the new plate pretty well so don't want to take any chances.....should be back on the water by the weekend I hope!
The condition doesn't look too terrible -- I've seen worse. But you can't really tell much from engine hours. Wear is dictated more by how much sand and debris have been run through the pump.
If you replace it, consider the Hardin Marine pump, which has a replaceable wear plate.
Comments
or so I thought-well, spent the weekend over around the Daytona area with no issues, ran fine.....we got back home on the trailer and I wanted to flush the salt, had planned on putting in the river but got back to late....so I grabbed the muffs, Keep in mind I have a 1/2 closed system and I also have two raw water pick ups: the foot and a thru hull. I turned off the thru hull, fired it up and looked to see that I had water coming from the back and was good so went about some other business in the cabin when I heard it start squealing- I was right by the key so I turned it off. I looked to make sure nothing had happened on the water supply side and was good so I fired it back up- looked underneath and no water flowing. Now, from the start of working on this pump, I have always been concerned that since it has two water pick ups and the thru hull looks like the largest supply source for water, did I just prove myself right, in a very painful way?
* one Engine Coolant Temperature (ECT) sensor measures the temperature of the closed-cycle coolant. This is what's shown on the gauge. The sensor is next to the thermostat.
* two Engine Manifold Coolant Temperature (EMCT) sensors measure the temperature of raw water exiting the port and stbd exhaust manifolds. Temperatures over 212 deg F will trigger an alarm and reduce power.
Have you tried disconnecting the pump output hose to verify that it's pumping?
If an impeller overheats from running dry, the ends of the vanes will turn to dust and it'll be unable to move water.
(A thru-hull with no seacock?! No boat-builder would sell a boat that way. Gotta be a user installation by somebody that doesn't know boats.)
Well, it's pretty easy to clear the heat exchanger. Take off the end cap (one bolt, and pry it off with a screwdriver) and you'll see any pieces that made it that far. If any small pieces made it into the tubes, they should get flushed downstream when you repair the pump. Or you can take off both ends and go after it with compressed air or a hose nozzle.
If you replace it, consider the Hardin Marine pump, which has a replaceable wear plate.
http://rinkerboats.vanillaforums.com/discussion/comment/8788#Comment_8788