89 Suzuki DT 75 water alarm

Signals at high speed 3000 rpm and up, will turn off as soon as rpm is reduced even a little only to come on again after a short while.Does not seem to run hot to the touch. can the thermostat open too late, (at boiling point opens wide when tested on the stove in water) and cause the pressure relief to open and drop the waterflow indicator? have done plenty, new gaskets,pump kit,flow indicator sep03 worked perfect after that, now starting again.Question the old relief spring is not up to its job...or is something else?

Re: 89 Suzuki DT 75 water alarm

You can do a search for some of my old posts. I had similar problems with overheating at high speed on my DT85. The temp sensors do fail and sometimes give erroneus signal. If the engine is not overheating that may be your problem. These engines had some head gasket issues and if yours has never been replaced you might look into a new head gasket but check the obvious first. Does your boat have a temp gauge? You can (I'm told) buy an infrared thermometer at Radio Shack to check the temps on various parts of the block and head. The heads will run hotter than the block. Ultimately after fixing all the cooling issues I retarded my ignition 2-3 degrees and haven't had a problem since.

Re: 89 Suzuki DT 75 water alarm

Took a closer look.The alarm system does not have a heat warning. Further inspection found the temp sensor wiring does tie into the water alarm and this may be the problem. The head gasket was replaced on 02. Do not have a temp gauge to get a number reading.This will tell alot. Do you know at what temp a good senson will say is hot? Handchecked the discharge water at the time and was not hot at the rear and after shutdown the side could get hot to the touch when the last of it drained out. Do not know the timing setting either but that's a good idea if needed. Thanks...

Re: 89 Suzuki DT 75 water alarm

The overheat sensor is set to alarm at 237 deg F. and wont shut off until the temp goes below 194 deg F. This is a metal to metal sensor so it measures the head temp not the water temp. I'd say anything under 200 is OK at WOT. I have installed a Teleflex aftermarket temp gauge on mine and it usually runs about 180-185 (head temp) at WOT. You can buy an infrared (point and shoot, no contact) temp gauge at Radio Shack I'm told which could confirm whether or not the engine is actually overheating. You should be able to lay your hand and keep it there a bit on the top of the cylinder between the flywheel and the cylinder head without burning yourself if its not overheating. The heads will normally be hotter.

Re: 89 Suzuki DT 75 water alarm

Was none of the above. Recent trip to the lake no need to run high speed because water alarm sounding right from the dock.Progressive worse syndrom as before. Used a infared thermometer. Idle temp varried about 10 deg or so with an adverage on middle cycl 133 deg. Lower cooler and top @ 138.Thermostat reading from its cover opened around 100, never showing over 112. Passing good water out the rear. Removed the flow sensor and reinstalled without the screws rotating it from side to side the alarm kept off for a while before coming right back on. Hey went fishing anyway with the trolling motor,just not a run of the lake day. Sensor test in water is a real sinker. looks ok but is waterlogged. Back to Suzuki and explained they placed it as a warranty item and swapped it out for a new. Said the old thin ones had the problems these newer design occasionaly a bad batch, may be the case. either way no comparrison in the flotation of the two the old like a dead log and the new a true floater. Makes the differance in the alarm system. My concern is the design on this model the float sits next to meat inside the head. After shutdown the water level drops and the heat effect on the sensor. Its not a true float, but keeping the water out of it makes the differance. Bunch of these models are out there...will run the new sensor and see what happens.......