motor alarm

I was wondering if someone might be able to help<br />me.<br />Please be patient with me as I am new to this forum.<br />I have a 1984 Suzuki DT 60 2 stroke that starts easily and runs sweetly. However after a few minutes of running at full throttle one of the motor alarms goes off.<br />It is not the oil alarm as I have disconnected that to try and find the problem, it can't be overheating as when I turn it off it is OK again after a minute or so.<br />Any help will be much appreciated.<br />Cheers PB

Re: motor alarm

I have a 1987 Suzuki DT85 that did something similar. <br /><br />1. Verify if engine is overheating. Your description says its not but your method is faulty. An overheated engine will cool off after a few minutes and then heat up again and set off the alarm again. If you don't have a temp gage place your hand on the block between the flywheel and the cylinder head. You should be able to hold you hand there for 5 seconds or so. It should be warm to hot but not so hot as to burn you. Better yet obtain a heat crayon at the dealer and mark it there. That area should be less than 165 degrees F.<br /><br />2. Verify that the water pump is pumping a good pee stream, if not replace impeller.<br />3. Verify that thermostat is working properly, if not replace thermostat.<br />4. Replace heat sensor in head.<br /><br />After a new water pump, thermostat, and head gasket and removal of corrosion blocking coolant passages, installation of temp gage, my alarm would still go off after 3 minutes at WOT. I had to replace the sensor which was functioning but overly sensitive and setting off at too low a temp. Good luck.

Re: motor alarm

Thank you for that Jim,<br />I did replace the whole water pump assembly a couple of months ago and I had it checked out an outboard mechanics and said it was pumping plenty of water.<br />I bought a new thermostat to fit however all the head cover plate bolts are seized and I was looking for some ideas before I attempt to free up the bolts or take it to a professional and pay heaps.<br />I will try as much as I can.<br />Thanks again,<br />Cheers

Re: motor alarm

In fact I snapped one of my thermostat bolts off the first time I removed it. Snapped a cylinder head bolt off later also. Got very good at removing broken studs. Your story might not end like mine. Ultimately my sensor needed to be replaced, but in the process I also found that my cylinder head needed the passages cleaned and I needed a new head gasket. Were it not for the snapped bolts, all of this would have been relatively easy. I also found that 2 months after I had replaced a perfectly good thermostat, the new one not only froze shut but I found out they had sent me the incorrect higher temp one (for artic climes I guess).