Overheat problem

[Barfly]

Last week I thought my boat was overheating, even though no sensor sounded. I replaced a broken ground wire and launched it tonight and sure enough after about five minutes the sensor let loose. I had the lower unit off the other day to change the impeller and found that it didn't need it. I wonder if I might have put the impeller in backwards when I put the whole thing back together? What else could cause it too overheat?
If you didn't read my post last week, here's the story in a nutshell. Went out (Lake Michigan), set lines, wind kicked up, pulled lines, hauled ass in until motor started losing power and wouldn't go over about 10 mph. I thought it was a loose throttle cable, but no. It wasn't a fouled plug or a fuel filter. Someone mentioned that it could be a rev-limitor caused by an overheating problem which leads me back to the beginning of this story.
By the way, the impeller looked good, no cracks or broken parts.
Oh, and it's a 1984 Suzuki DT115.
HELP!
Richard

[Barfly]

Forgot to say that there was no water coming out of the "pee hole".
Thanks,
Richard

[SalmonBum]

If the impeller was installed backwards, they will still usually pee out some water, if not right themselves.

If your not getting water Peeing, you must have a blockage. Try using compressed air to blow things out.

Thermostat????

[Damark Marine]

You have no water coming out of the tell tail hole after the water pump change. Just curious did you have water coming out before the replacement ? If you did then look for what might have gone wrong. You cant really put impellors in backwards, they just flip over if they are new to the correct way. If we have a good properly installed water pump & still no water peeing then we need to clean out the pee hole & snoop around a bit.


You need good compression, spark & a working fuel system to make it run did you verify good hot spark on all cyls as well as good compression? I can help but I need a little more info.

[Barfly]

The weather had kicked up very suddenly and I didn't notice if the tell-tale hole had a stream or not initially.
Even though it's overheating the engine is running well and starts right up.
I took out the thermostat and checked it on the stove in a pot of water. Opens at around 130 degrees. Does that sound right?
I'm going to leave the thermostat out and back flush the system with water from the garden hose through the thermostat hole. Maybe there is a blockage of some sort and that might cure it???
Any other help would be GREATLY appreciated.
Richard

[john warren]

have you in the past had to replace an impeller? was there chunks missing? did you get them all out? if not they are in a coolant galley somewhere and need to be removed. or..... your perfectly good ompeller,,, died,,,it happens. specialy if you did turn it the wrong way when putting it back in. if this is the case,,,,,refer back to the bits of imeller needing to be gotten out.

[Barfly]

Well, it seems as if when I put the impeller back in the little key slipped out and it wasn't able to turn. I put it back together correctly and fired it up in the driveway. I'm now getting water out of the tell-tale. Heading down to the ramp in a minute too see how she goes on the water, and I'm keeping my fingers crossed.
Richard

[Damark Marine]

Sounds great let us know how it turns out. I hope all is well now.

[TONGA]

Just a side note always a good idea to replace the tube seal also. And just because an impeller is not broken dose not make it good ,they get old ,hard and take on a set and they really need to flex to work properly.