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SUBJECT: # 27335: Yammie Buzzer Problem NOT solved! Incredible!!!!
Submitted by speckledtrout (68.152.78.34) from LOUISIANA on 6/27/05 4:15:00 PM
Guys, just when I thought I had it licked, NOT! I ordered and installed 4 new temp sensors for each motor. Turns out the overheat buzzer is still sounding. Thus, NOT the sensors themselves. Now for the weird part!! I can unplug the sensors and run full throttle all day long. Motors run perfectly and DO NOT overheat. Wiring harness problem??? Whew, this is getting old. Anyone want a steal of a deal on a 26 seacat, loaded, with two yammie 130's????
- 6/28/05 12:31:00 AM
Submitted by
Shadetree (70.246.125.86) from TEXAS says temp sensors
I would STILL suspect the sensors. The reason I say this is that I have seen quite a few sensors for many brands act stupid. A new sensor is no guarantee.Temp sensors maintain an open circuit in the normal operating range. As they heat up they close the circuit and complete a grounding path which the ECM (newer model motors) recognize and limit revs and the grounding completes the circuit to the buzzer too.
What is the closed temp threshold spec for your sensor? I'd guess around 140F. You need to look it up. Bench test each sensor by gradually heating up small glass of mineral oil (can even use cooking oil) with the sensor hooked up to multimeter in continuity check. As the sensor reaches its spec'd threshold (you'll need a thermometer too) you should achieve continuity and buzz or peg your meter. Using a hairdryer directly on the sensor might seem like a good idea, but it just doesn't work that great for a reliable heat source and you usually hit your threshold without any idea of the exact temperature.
Here's the kicker. I once tested a single sensor over a dozen times and it passed each time on the bench but would throw me a heat alarm sometimes on the water. I KNEW I was wasn't overheating because I have independent temperature guages and I could hold my hand on the heads while the motor was running and the buzzer was going. I had also bench tested my tstats and confirmed that they were working just fine without ever hanging up even for a second. I finally got the buzzer to fail on the bench, but it took over a dozen test sequences. Why? I have no idea.
My initial suspicion is that you still have a bogus sensor, new or not. If you KNOW your not overheating, then I would unplug one sensor at a time and run for a good while. Then hook it back up and unhook another sensor for a good run. You might just find your bad sensor through this process of elimination.
PS. your buzzer is probably common to the oiling system so make sure you don't have an oiling sensor or pump problem. I'm not specifically familiar with your motor, but rev limits and buzzers can be common to oiling events in some system.
- 6/28/05 9:46:00 AM
Submitted by
speckledtrout (68.152.78.34) from LOUISIANA says Thanks for the detailed info!
Thanks. Will be following your advice and post what I find. If your suspicions are incorect re: bad NEW sensor, then I may just condemn the sensors and install temp gauges.
- 6/29/05 11:05:00 PM
Submitted by
seahorse (68.205.19.217) from ALABAMA says temps
If there is a salt or mud buildup inside the cylinder head covers in the temp sender area, there could be a "hot spot" that would trigger a temp sender even though the rest of the motor is not overheating. The only fix in that case is to remove the heads and covers and scrape out the deposits and put it back together.
