Impeller?

[Twins 57 Fan]

Just had my boat on the water. It was only sputtering out water a little bit when idling or going slow. After I would speed up then steady stream would come out.

Is this an impeller or water pump?

Help!!!

[john.wells]

It could be the impeller, or also possible restriction in the water jacket. A lot of times, there might be a little bit of weeds or grit where the water spits out, as this tends to be the smallest opening in the system. Take the cover off and follow the tube from the cowling to where it connects to the engine. With the lower unit submerged or with "muffs" on, start the engine and let idle, then pull the tube off from the outlet port of the engine to see if the flow is better. If it is, clean the gunk from the cowling port. If it still just sputters out, you might only have to flush the water jacket. If you flush the jacket and still have poor flow, the culprit is most likely the impeller. When was the last time it was changed?

[john.wells]

Also, check the inlet area for obstructions.

[Twins 57 Fan]

not sure. just bought the boat.

Wouldnt the obstruction happen even at fast speeds?

[john.wells]

Not necessarily. Is the stream nice and strong at faster speeds, and in good stream form, or does it kind of spray?

[Twins 57 Fan]

the stream is very nice at faster speeds.

[john.wells]

what kind of outboard? size and make.

[Twins 57 Fan]

75 tracker by mercury 1996

[john.wells]

I would look at the impeller, givin the age of the motor and not knowing if it has been replaced. It wouldn't hurt to flush the water jacket, either.

[Twins 57 Fan]

what exactly is the water jacket? thanks for your help, this is my first outboard.

[john.wells]

the water jacket is the plumbing in the engine itself that keeps the engine cool.

[Twins 57 Fan]

How would a guy go about flushing that on his own?

[john.wells]

I'm not too terribly familiar with that engine, but if it is like most Mercury's, there is should be a small plug, about the size of the lower unit lube drain plugs, and is marked "flush". It has been awhile, a long while, since I have flushed an outboard so I run the risk of steering you in the wrong direction. On that note, I am sure someone will get the right info to you. However, I believe it is as simple as making sure you have a good water supply at intake on lower unit and running motor with the flush plug removed.

[boatfixer]

I would change the impeller without hesitation for no other reason than piece of mind. There is also a thermostat. Did you run the motor long enough to heat all the way up? If not, this could also explain no flow at idle right away. When you rev it up enough it will force the thermostat open. But as I said before, replace the impeller first and lets go from there.

[Valv]

Replace the impeller before anything happens to motor. $ 20 part that will save $ 2000 motor.

Once you have it apart, you can see if it's the whole pump that needs attention, which will involve getting a kit which cost around $ 50 and includes impeller, new housing, new wear plate, gaskets, woodruff key, etc.

[marine_man]

Replace the impeller.. and see how things are looking after that. Bruce mentioned the thermostat as well, which can get gunked up from time to time.. but if you aren't sure when the impeller was last replaced, now is as good of a time as any.

Good Luck!

marine_man

[MuskieJunkie]

I had a 94 Merc 60 hp and it use to clog a couple of times per year. It was always in the same spot too. The last rubber hose that leads to the indicator (pee) hole. I would undo the 2 hose clamp, take it out and use a coat hanger to reem it out.

Everytime it happened to me it would completely clog, not the symptoms you described. I would change the impeller, especially since you just took ownership and you don't know the history.

[Twins 57 Fan]

I replaced the impeller... Still nothing. I the took off the thermostat and checked it and it was working fine.

Correct me if I am wrong here... The impeller is pumping water in to the motor to cool it off, it is holding on to the water until it reaches 130 degrees and then the thermostat opens up and pees out the hole. Is 130 degrees the running speed for this motor? why wouldn't it want to pee out all the time?

Help!!!

[boatfixer]

I would verify the engine temp. I use a laser thermometer, you can use thermomelt sticks also. Another simple but not as precise way is feel the top of the block. If you can keep your hand there, it's cooling.

With Mercs with thermostats under normal function, when you first start up you won't see any (or much of) stream until:

1. You increase RPMS forcing the poppit valve open

2. The engine reaches temperature and the thermostat opens.

Basically, the thermostat is keeping water in until it warms up. However, if the rpms increase the popit valve will open to release water pressure in the block.

Some how, verify you are cooling.

[marine_man]

Now that you're certain you've got a good waterpump, have you checked to make sure there's not something blocking the telltale water stream tube?

marine_man

[Twins 57 Fan]

Checked that. everything seems to be fine. I guess it just needs to get to a good running temp before the thermostat opens up. Who would of thunk it.

Thanks for everyones help

[delcecchi]

The water comes out the hole all the time (or is supposed to), regardless of the thermostat being open or not.

[marine_man]

Well, since you replaced the water pump, and you said you had a good stream at higher rpm's I'd run it this weekend a bit and check the water stream at idle then and see what it's like.

marine_man

[Twins 57 Fan]

Del...

How can it get water through the thermostat if it isnt open? there is no where for it to go?

[delcecchi]

I think the water for the "telltale" comes from before the thermostat, or there is some bypass. Every motor I have had or seen starts shooting water out as soon as it is started. That is how you can tell the water pump is working. And the water is cold at the beginning.

So if you don't get water out of the telltale then either you messed up the impeller installation somehow, or something is plugged (not unheard of for crud or bugs to get in the little hole), or maybe the tube came loose under the console.

Your car allows some water through the thermostat when closed.

I would think an outboard would do the same. Look at any outboard that starts up on a local lake. you will see.