Nissan 25c2 cooling issue

[mcrean]

I just replaced the thermostat and rebuilt the water pump in my 1987 Nissan NS25C2. However, I still have no water coming form the outlet nozzle. Now, I don't have a temp gauge, but I let it run what should be a sufficient amount of time to see flow occur from the outlet.

So I have two questions:

1) I don't think this motor has an overheat alarm or a high temp shutoff, nor do I see a temp sending unit to hook a gauge to. How will I tell I it's overheating or rig up a gauge to it?

2) Where else might I look for the cause of no water flow form the outlet if the thermostat is new and the water pump as been rebuilt?

 

[TOHATSU GURU]

Re: Nissan 25c2 cooling issue

1) Aftermarket heat sensor kits and if you put your hand on the block and leave skin its too hot.

2) Is your engine actually getting hot? The majority of the water is expelled through the propeller where you can't see it.

 

[mcrean]

Re: Nissan 25c2 cooling issue

Elvin,

1) Any source/recommendation you can point me to for the aftermarket heat sensor? Thank you, but I need all my skin intact

2) I'm running it with the flusher. Plenty of water spewing through the prop. Again, without a temp gauge or indicator I have no idea if it's running hot. I don't think this engine has an audible alarm, either. As I understand it, if all is working well there should be a visible stream from the outlet (or as my son put it: it should be peeing out the little hole.) My assumption then is there is a problem. Is that an incorrect assumption?

 

[TOHATSU GURU]

Re: Nissan 25c2 cooling issue

1) iboats

2) I think you just have a stuck pee tube. Poke a wire up through the tube while the engine is running and see if you get flow.

 

[mcrean]

Re: Nissan 25c2 cooling issue

Okay, I checked for obsturction at the pee port and followed the tube back to the motor and tried there. Even tried running it without the tube attached and nothing comes out the motor either. I suppose then it doesn't appear that water is getting up to the motor.

Perhaps I need to pull the foot again and check for obstruction in the water tube?

 

[TOHATSU GURU]

Re: Nissan 25c2 cooling issue

You need to check and see if the engine is getting hot before you do anything else. Hand on block...No burn, not hot...If you scream, its hot and then you find the problem. If your a sissy you can throw some water on the block and see if its hot before you put a finger on it

 

[mcrean]

Re: Nissan 25c2 cooling issue

I'll try the water trick. Burn scars won't go well with my high heel shoes

 

[mcrean]

Re: Nissan 25c2 cooling issue

Elvin,

Okay, I tried the water on motor trick. It boils, so I guess the motor is getting hot. Recommended next step?

 

[TOHATSU GURU]

Re: Nissan 25c2 cooling issue

Put back on your high heels and take the boat to the ramp and run it in the water rather than on a hose or tub. Do the water on the block again. If it's still boiling off your looking at:

waterpump
restriction in the system
thermostat
block/head issue

Look in that order.

 

[mcrean]

Re: Nissan 25c2 cooling issue

Okay, since I couldn't find a purse to match my shoes, I went ahead and pulled the foot in the driveway and peaked at the impeller. It was chewed to bits. I pulled the water intake vents (where the ears go) and found shards of the old impeller clogging the input shaft up to the water pump.

Stupid me, I should have checked that when I replaced the impeller the first time. I now suspect that when I fired it up after initial replacement these shards were draw up into the water pump and blocked water flow, thus cooking the new impeller.

Elvin, you were probably going to say that's what I get for trying to be a mechanic in drag, so I said it for you to prevent your incrimination. :redface:

 

[TOHATSU GURU]

Re: Nissan 25c2 cooling issue

Actually I commend you for sticking with it. Many a mechanic has had to pull a L.U. back down to fish out a vane off of an impeller Oh and try ebay for a matching purse.