alarm woes

[fwfell]

Hello,<br /><br />I have a 1993 Merc 115, 4 cyl. serial # OD197784. It has been little used despite its years. I have had few problems other than a stator replacement in 1998 (that hurt a bit, over $1,00 at NY prices).<br /><br />I put the boat in this spring. It ran well for 2 brief trips. However on the 3rd trip, last week, the sensor for high temperature went off. I know that it's not the low oil because the sound is continuous, not at all beeplike. The sound was initially somewhat like the staticy sound of a fax connection. It then morphed to a constant high pitched sound, not too loud. At on point the noise stopped, but on restarting the engine, it continued until turned off.<br /><br />My water temp. guage shows no rise in temp., and the exhaust water stream continues to flow at a normal rate from the upper part of the unit. The engine runs normally despite the annoying and ominous alarm. In short, it certainly seems as if there's a problem with the alarm module/wiring that is giving me an incorrect alarm warning.<br /><br />Are alarm modules expensive? Are they a doable repair for a minimally proficient amatuer? Would using the temperature guage be sufficient to monitor engine temp? Dare I say it, could I disconnect the warning module and rely on the temp guage if lack of funds would prevent the alarm module repair for a few months? My wife hates the boat, my daughter needs braces, so a reprieve from major repairs would be a good thing, but I don't want to be foolish and pay for a new engine in the end.<br /><br />Any advice/suggestions would be a big help. Thanks!

Postscript: My mechanic came to evaluate this problem. He tested oil and temp alarms which went off as they should. Because the alarm I'm getting is a much less loud sound than the alarms for oil and temp, the mechanic feels that is's a short, recommended spraying copious amounts of WD40 behind dash and on engine at all wiring areas. The mechanic said overheating is not happening and that any major diagnostic effort can be done at the end of season. WHEEEW!

 

[grew14ft]

Re: alarm woes

I just went thru same prob with my dad's 1989 115. Thought it was overtemp sensor but turned out to be oil alarm module. When diagnosing the beep I rebuilt water pump, checked the thermostat for proper operation, and checked/cleaned poppet valve, all was OK. Temp guage never indicated engine was running hot.<br /><br />To see if its overtemp sensor or oil warning module that is causing the beep find the terminal block in the engine where the overtemp sensor wire and oil module wire are attatched to the alarm wire (in my motor it was brown/blue wire from alarm, black wire from temp sensor, brown wire from oil module). Remove the alarm wire from terminal block and run the engine. If still beeping then that wire is grounding out somewhere, fix the wire. If not beeping, then attatch overtemp wire and alarm wire to terminal block leaving oil wire disconnected and run again. If beeping then trouble shoot the overtemp sensor. If no beep then hook up oil wire and alarm wire leaving overtemp disconnected. If beeping then its the oil module, as was the case with mine. I have not fixed it, just leaving it dissconected and making sure I never run out of oil!!