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Question for Mtierney...
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| dauntless-n-miami |
Posted on 08/07/13 - 9:53 PM
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Regarding the "Heat Sensor" that you had issues with on your 115 Yamaha 2 stroke.
It appears my Yamaha 90 also has this sensor (only 1) located just above and to the right of cylinder 1.
The part number you supplied is about the same except with a dash after the ending number 10 and 2 extra zero's.
Mtierney, how did you discover that the sensor had failed? Were you able to run a voltage or ohm's test? Did you do a final on water test with your whaler to confirm issue resolved? I called today and spoke to the boat shop that has been working with me about this particular sensor and had they any previous failure experiences with it. The mechanic told me that he personally had not had any past issues with this component but that didn't mean it could not happen.
I did a continuity test on the sensor and it appears to be in an "open loop" condition with motor not running. In other words no continuity. The actual description for this sensor according to Yamaha is a; Thermo Switch Assembly. Did you post in my original thread that you had experienced similar symptoms as mine and never had an alarm signal or buzzer go off when motor began to run poorly?
Any additional info that you can offer will be greatly appreciated, thanks again...
Angel M.
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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| mtown |
Posted on 08/08/13 - 7:05 AM
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Angel,
I think you were referring to my post. My problem was similar to yours and as I recall I wandered into a Yamaha dealership in Solomans Island Md. while my wife shopped and I killed time. They were not busy and I described the problem to the service guy there and he made the guess. I think just disconnecting the part solved the problem, and I then purchased the part and inserted. This was in 2002 and I found the original receipt $55 for two of them.{I only replaced one}. I just looked at my 90 hp Yamaha and it is located where you describe.
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| dauntless-n-miami |
Posted on 08/08/13 - 11:13 AM
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Thank you mtown, I must have got my thread replies mixed up. I found some info from a few different forums on how I may be able to bench test the switch.
I now have the operating (engine ) temperatures for the Yamaha 90 so I should be able to closely simulate the "closed and open loop " functions of the switch with an external heat source (pot of heated water, etc., etc.). If it grounding out primaturely I may be able to see it with a mutimeter either by continuity or voltage readings.
Angel M.
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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| mtown |
Posted on 08/08/13 - 12:09 PM
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I am assuming that you can't easily put the boat in the water to test under load. If you can I would disconnect the leads to the sensor and try getting on plane. It has been a while but I am pretty sure that is how I proved it was my problem. The problem with bench testing is you can not predict when the sensor will malfunction. It took us years to find a fault in my wife's Jeep to find a $5 part that was failing and causing the car to die. That was with dealer and pro mechanics looking at it every time it was towed.
Testing with heat will probably not help. I seem to recall pulling the sensor from the block while leads were still connected. It was obviously not able to sense overheat but was still reducing RPM.
On the regularity of this failure, I have owned 4 different Yamaha engines in 27 years and the failure on the one was the only time, thus I still own 2 spares that I hope to never need. Not that I would sell because you know what that would mean.
Edited by mtown on 08/08/13 - 12:15 PM |
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| dauntless-n-miami |
Posted on 08/08/13 - 6:04 PM
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Hello again mtown, I can only water test on the weekends (unless I play hookie from work) to test.
I decided to bench test the thermo switch for the sake of getting familiar with it's removal from the cylinder head. As you predicted, no malfunction when tested. It came on (loop closed) when heated at factory temperature spec's of about 183 degrees F. and turned off (loop open) when cooled at about 150-152 degrees F.
I repeated the on and off cycles 3 different times in a small pot with boiled water and switch suspended at a constant level while in contact with water. Temperatures were measured with an infrared laser unit at the switches top center.
I will be water testing as soon as my carbs are returned and reinstalled. When I remount the Thermo switch I will implement a toggle switch with it own wire leads and matching terminals which will serve to interrupt output signal without having to unplug it. The factory leads are a bit difficult to get to and short, I would hate to break a terminal while water testing.
If this switch isn't the problem it's going to get expensive from this point on. There's only 2 more suspects that can cause a safe mode condition, Charge Coil or CDI unit. The mechanic has vigorously checked the spark condition with no issues detected and from his experience when the CDI unit begins to act up it affects idle and timing.
The oil tank float and switch have been checked and are functioning properly. There is a total of 4 components that can cause my motors safe mode symptoms and I've mentioned them on here.
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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| mtown |
Posted on 08/09/13 - 5:32 AM
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Good luck, I hope my guess is correct as it will be an easy fix. It sounds like you have done a through test and it is working. Is there any possibility the lanyard safety switch is malfunctioning?
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| Mtierney |
Posted on 08/09/13 - 6:14 AM
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Sorry I didn't reply sooner, but mtown was the better source of info. I will investigate this if the problem continues on my yamaha.
1985 Newport 17 w/ 70 yamaha |
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| dauntless-n-miami |
Posted on 08/09/13 - 7:44 AM
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Sorry Mtierney for the mix up, mtown was very gracious in clearing up my confussion.
Mtown, I haven't really put the lanyard through a real test except for disconnecting it and trying to start the motor, which it will not. This is a good sign, yes? I have read where some will get an alarm/buzzer when lanyard is disconnected and motor start attempt is made. I do not experience the alarm/buzzer condition when I try?
A possible problem here???
I will not be making any progress this weekend, the Yamaha mechanic inspecting my carb's has been out sick for the last 3 days so maybe my luck will change for next week and I'll get them back with a report.
Till then, my little Dauntless will sit saddly on her trailer till this gets figured out...
Thanks again for the all the help...
Angel M.
Edited by dauntless-n-miami on 08/09/13 - 7:53 AM
1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke |
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