Limits that trigger the alarm
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=35689
Printed Date: November-17-2024 at 7:41am
Topic: Limits that trigger the alarm
Posted By: spiralhelix
Subject: Limits that trigger the alarm
Date Posted: April-03-2015 at 6:15pm
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I have searched a lot today looking for the threshold limits that trigger the alarm, but can't seem to find them. I read through the manual and engine manual in the reference section but didn't seem to find the answer (or missed it). Most of my forum searches just talk about problems associated with oil, temp, and voltage, but never what actually triggers the alarm. In the 89 SpN, there is only one alarm light (contemplating adding separate indicators), so i don't have a good way to tell which one is triggering the alarm. For reference, my voltage gauge said 13 (so doubt it is that), oil pressure was 50-60 (but bounced around a lot), and engine temp held solid at 160 deg. Along the same lines, the fuel gauge says tank is full, but a VOM test of the posts of the sender say 138 ohms. I am betting that problem is a ground or power issue as the alarm and indicator were very intermittent. Running new lines tonight. BUT... What are the oil, temp, and voltage limits that trigger the alarm (high and low)? It would be nice to know for the future to help determine which part of this floating contraption one would need to address. Thanks! PS. Back to the fuel sender...the resistance on the fuel sender side of the harness unplugged says 138 ohms, but when you plug in harness to the dash wiring, the gauge (pink wire and ground) say 50 ohms. Hence the reason I think there is a wiring issue. I'll run some more test. I was just mad and frustrated by the time we got back from the dock. 
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Replies:
Posted By: 8122pbrainard
Date Posted: April-03-2015 at 6:29pm
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Colin, Don't any of your gauges work? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: spiralhelix
Date Posted: April-03-2015 at 6:53pm
Clock works  Hour meter, weren't out long enough to see a change...plus I wouldn't know what a non-working hour meter looks like other than the hours not changing at all. Speedo worked, but is non-electrical other than the light Tach, showed idle at 650-700. We didn't really open her up. so never really saw much change. Just idled around the river for about 5 min. Fuel, shows completely full even though there is only a half a tank. Temp, read 160 deg once the engine warmed up and stayed that way oil pressure, was generally between 55-60, but at times would flicker higher or lower. I guess this was what was concerning me. Is that a level that would trip the alarm? or is more like 75-80 gonna trip the alarm? Volt, stayed at about 13 most of the time. The alarm would start sounding..almost like a weak TV signal...hazy and then either full on, or full off. Mostly full on. so not fun even for 5 min. |
Posted By: spiralhelix
Date Posted: April-06-2015 at 11:55am
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Update: as stated above, fuel gauge was "full" no matter what the actual level was. I pulled the gauge out of the dash and connected it straight to the sender by connecting the + post of the sender to the "S" post on the gauge using a cable with alligator clips, connected the Gnd post of the sender to the Gnd post of the gauge, connected the + post on the gauge to the positive terminal of the battery. Result, the needle jumped and then settled at 1/4 tank (which seems about right based on the level). Seems like the gauge needed a bit of a "reset". Once I connected it back into the dash, the ohm reading remains at 138 (whereas before it would drop to 70 post harness) Disconnected all harnesses and connections and connected everything back up one at a time. As something was connected, it was tested (and anything before it). With everything back, all electrical components seemed to be right. Took the boat back to the river. Clock-Worked Hours-Worked (i watched the little red dial tick away) Speedo-couldn't test (we never got the boat off the trailer as the engine wouldn't stay running  )Tach-let's not even discuss it can't get a good reading if it doesn't stay running.Fuel-initially showed 1/4 tank, filled up the tank, now reads Full Temp-after the engine warmed up, read 160 deg. Oil Pressure-stayed around 55, but at times would go to 60 psi Volts-stayed around 13. The alarm continues to sound  or does it's hazy fade out, only to return either after a couple minutes or after having to restart the engine. There was no consistency to when it would get "hazy".Since the alarm is controlled by what seems to be only two sensors: oil, temp, and also by the voltage. One of those three has to be tripping it, correct? So i would assume that if the voltage increases above 14 or falls below 11, the alarm would sound? and since this is controlled by the alternator, if that isn't operating (as in the engine isn't running, but key is turned), the alarm sounds? With the engine temp I am assuming that the alarm sounds above 200 deg? Oil pressure: im at a loss. I don't know what constitutes high or low pressure. 55-60 seems normal to me and some sources don't seem too concerned about high pressure. Other sources indicate pressure that falls below 30 psi is reason for concern. But again, it leads me to the question, what are the limits for the alarm to sound? or another way to put it...when do I need to be concerned about gauge readings? |
Posted By: SNobsessed
Date Posted: April-06-2015 at 12:57pm
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The alarm circuit is a very rudimentary design, this is why it is unstable & goes off prematurely. The voltage regulation is just a zener diode. The 'brain' is an op amp. Most of us have just unplugged it. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: spiralhelix
Date Posted: April-06-2015 at 1:43pm
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Zach said the same thing. Since that is the case, I will also disconnect it. I think that is why the PO destroyed the buzzer. Prolly got sick and tired of hearing that high pitch all day Anyone wanna purchase 3 brand new buzzers??? Zach also confirmed that aside from the temp gauge getting high (above 200), the only other concern would be if the oil pressure changes dramatically in a short period of time. |