HOT LIGHT

[slxtra]

Hi, I have a 99SLX with a 1050 with about 17hrs on it. Recently the HOT LIGHT warning keeps coming on at about 5500 rpm and over and then cuts out the engine to low rpm range. Can't go top speed for long! I check the engine and pipe for heat but it seems cool.
I've flushed the engine and checked and cleaned thermostat. ANY IDEAS?
P.S. I only do lake water, NO SALT. THANKS, MIKE [img]/graemlins/angryfire.gif[/img]

[Bryan Glynn]

Replace your overheat sensor, they go bad.

[John Sharp]

I have 00 SLX with abotu 7 hours on it anf the Hot light keeps coming on also. I think I may have a bad sensor also.

[slxtra]

Is it located on the pipe? I'm not sure. If it is, is there a easy way to get it off because it's hard to get at.

[pcalonge]

The overheat sensor for a 1050 motor is located on the side of the exhaust manifold, underneath that big red expansion chamber, and yes, it is very difficult to get to unless you remove the waterbox (muffler), and the expansion chamber.
Even if you can pull the hold down bolt and the keeper (10 mm head on the bolt), (and it is possible), the rubber sensor is very difficult to work out of the manifold even with the pipe removed. (I use a hooked pick).
I don't know if your hull has relief cutouts over the port side expansion chamber bolts or not- my 98 SLXH had them, I had to cut some with a dremel & sanding drums on my 97 XL 1050. It sure makes it easier to remove the bolts.
Anyway, pull your muffler. Loosen the 4 bolts on the top of the expansion chamber. The 2 inner bolts can be removed, the outer (port) bolts have to come out and go back in with the pipe. Work the pipe out toward the rear of the boat. With the pipe removed, remove the sensor keeper with a 10mm wrench. Remove the formed rubber sensor, carefully working it out of the exhaust manifold with a pick or a couple of jewelers screwdrivers. Looking at the maze of wires coming up on the starboard side of the rear of the engine, tug gently on the sensor wire untill you identify the correct wire going to the "brain box" over the battery. Work the correct wire and the sensor under the motor. they typically run between the engine cradles. If you have a late model, the wire goes to a plug on the box. Older models like mine require removing all the allen bolts and splitting the case, then locating the correct wires (note the proper spade connectors!) and working them out through the grommet.
The new sensor is installed in reverse order. Wires fed through the grommet, hookup to the proper spade connectors, put box halves together after inspecting the o-ring and applying silicon grease, tighten allen bolts (use Locktite 242, the blue stuff). Fish the new sensor under the motor between the engine cradles. Smear the new sensor with silicon grease and work into the exhaust manifold, replace keeper, use Locktite 242 on the bolt and snug up- don't overtighten.
Take a new expansion chamber gasket, spray liberally w/coppercoat sealer, let set up and place on the manifold. Replace the pipe, remembering to put the two port side bolts in the flange before setting it in the hull- I use a rubberband around the top of the threads to keep them from falling through the flange and hanging up on the manifold. Start these 2 bolts. Start the inner bolts after applying 242, and tighten, using a torque wrench. I believe these bolts should go to 25 ft/lbs- download the engine installation instructions from the SBT website, they give the correct settings, and by the way are well illustrated and will help you perform this operation. Replace the muffler and go ride.
I know this sounds complicated, but it really probably takes less time to do than it took me to type this. If you have really skinny arms and double-jointed fingers, you can probably change the thing w/out removing the pipe, but one attempt made me a believer in doing it the long way.