Volt meter gauge pegging at 18V
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42712
Printed Date: November-23-2024 at 9:37am
Topic: Volt meter gauge pegging at 18V
Posted By: Webster
Subject: Volt meter gauge pegging at 18V
Date Posted: May-01-2018 at 9:01pm
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I'm finished with the restoration of my '83 Ski Nautique 2001!! Everything seems fine, but i really don't know for sure how smooth it should run, top speed, etc. If someone could please help me answer a few questions, it would be much appreciated. First, my new gauges are great, but the volt gauge show's mid 12v -ignition on - not started. When started, it is pegged at 18v. I purchased a new alternator. Meter reads 14 - 15.8v when running at the alternator and also battery. The "i" terminal on the Volt Meter is hooked to a lead from the "IGN" terminal from the ignition switch. (purple wire) - Alternator (orange wire) to the "S" and black ground wire to the "G" on the Volt Meter. The wiring diagram I copied off this site, shows the battery (red wire) hooked directly to the "I" on the back of the volt gauge, not the purple wire lead off the "IGN" as above. If I switch that wire to the "bat" (red wire) on the ignition switch, it still reads 12v, but it will always stay on, regardless of the position of the ignition switch. Makes sense i guess, as it is directly tied to the battery. Is this normal for the volt gauge to stay on? Not sure yet if this will correct it pegging to 18v when running, but I thought since the purple wire comes from the coil, maybe this is why the volt meter is pegging. (I converted to EI, so the resistor is within the Flame Thrower Coil). 2ND question: I have a 351W engine, reverse rotation, standard heads, holley 4bbl carb. After about 10 hours it's top speed is about 42 to 43 mph on medium rough water. Is that about right? I've seen others boasting of 50 to 55 mph, but wasn't sure if that was GT40 heads, etc. Final question: I have a new propeller. There was no foam replaced in the floor, just stringers and glass. I notice some vibration from about 20 up to 43 mph, but not bad. It seems more to be related to having a 351 engine roaring in the middle of the boat. So, maybe the foam dampens the noise/vibration a bit?I Thanks for any thoughts.  ------------- Ski Nautiques deserve a second chance...... |
Replies:
Posted By: gt40KS
Date Posted: May-01-2018 at 11:59pm
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Top speed seems about right for a std. 240hp 351 and generally the GT40's run around 50 or so with standard prop. Some folks may modify the engine or replace the prop to get higher top speed. You said you purchased a new alternator ... I'm hoping it wasn't an auto parts store variety - it really needs to be marine specific. But the 18+ volts is not right, don't know what's going on there .... bad internal voltage reg? Maybe someone with experience in your year range has an idea on that. You don't by chance have a dual battery system? Also, I wouldn't use the 'BAT' red wire for the gauge, use the purple from the alt. If an external voltage meter shows 15v +/- on the purple directly off of the alternator, I'd suspect the gauge is malfunctioning. By the way - Nice job on the resto! Do you have other pics of your boat on CCF? If not, let's see more  ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: KENO
Date Posted: May-02-2018 at 8:26am
Bit of a confusing post, but if you have 15 volts at both the battery and the charging wire from the alternator,when the boat is running, there's no way you can increase the voltage from there unless you have some kind of electrical magic going on  If you had say 20 volts or so, from the alternator,that would be a different story. Why don't you take your multimeter and check voltage at the back of the installed voltmeter and see what it says That should tell you the installed voltmeter is reading wrong. Edit see my post below this one about your s terminal. As far as your speed, info like RPM and prop brand and size and whether you're using GPS would be helpful to know too |
Posted By: KENO
Date Posted: May-02-2018 at 9:25am
Not knowing what kind of voltmeter you installed, if you have anything hooked to the s terminal on the voltmeter you probably didn't follow the directions. Typically you only need a wire from your i terminal on the ignition switch to the i terminal on the voltmeter and a wire from the g terminal on the voltmeter to ground. Nothing gets hooked to the s terminal on the voltmeter. Nothing at all If you hook up the meter correctly on the i and g terminals and have 12 volts going to the s terminal the voltmeter will peg high. This sure sounds like your problem, so take the s wire off and see how the voltmeter works. Then if that works, you'll have to look at the diagram to figure out where to hook your orange wire.which would probably be to tape the end and hook it to nothing. You're probably using the early PCM diagram that shows ammeter wiring and tells what to do if a voltmeter is used instead. |
Webster wrote:Posted By: 8122pbrainard
Date Posted: May-02-2018 at 10:17am
Ken, What would the intended purpose of a "S" terminal be on a volt meter? ------------- /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: JoeinNY
Date Posted: May-02-2018 at 10:22am
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I haven't really been in too many stock 2001s but I would say 42-43 is a bit on the low side, 44-46 is probably healthy. Not too many run an honest 50, generally they would be significantly modified or came with a 454 from the factory. An honest 55 is likely to take 350 hp or more. There really shouldn't be much vibration in a properly aligned boat with a new prop and a straight shaft - its possible you are missing on a cylinder or something is not as straight/balanced or aligned as it should be. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: KENO
Date Posted: May-02-2018 at 10:52am
It's there to confuse people When the manufacturer uses the same housing for something like a fuel gauge, oil pressure gauge or water temp gauge that has a sending unit it's used for that incoming signal. If you hook up the g and i terminals on a voltmeter and it reads 12 volts, as soon as you put 12v to the s it pegs. If you just hook up the g terminal to ground and hook up 12 volts to the s with nothing hooked to the i terminal it pegs too. Verified all that with a spare volt meter this morning We'll call that this morning's experiment |
Posted By: 8122pbrainard
Date Posted: May-02-2018 at 11:05am
Got it! Sounds like not only do they use the same housing, they also use the same internals since all are basically a volt meter. Then they just put different faces on them for the desired reading. Cheap Chinese?  David, As ken mentions, next time read the instructions!! ------------- /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: Hollywood
Date Posted: May-02-2018 at 11:11am
KENO to the rescue again 
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Posted By: Webster
Date Posted: May-02-2018 at 11:30am
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Fantastic input gt40, KENO, Pete and Joe. I know it was a lot of info and confusing! Yes, the alternator is a marine alt. It's a Sierra International gauge called Sahara. I ordered another volt gauge to be sure and both read high AND the instructions are worthless!! I even called the help line and the guy said it was hooked up correctly, that the NEW alt probably was bad...... I will disconnect the S terminal wire, run a wire from the i terminal on ignition to I terminal on Volt gauge, then a ground wire to G. Thank you! The Prop is an ACME 540 3 Blade 13" x 12" Propeller. When checking the gap on at the shaft and tranny, it was a bit over .003 on one side. I attempted to adjust, but when I tightened it all up, it was right where it had been. So I thought, "it's not THAT much off" and wrapped it up. I will have that remedied if I can figure out who can do it?? This is my first experience with a boat, so, mostly learned through you guys, google, and whatever my stringer guy knew, which was pretty much only about the structure of the boat. I live in Knoxville, TN and am not sure about where to have this kind of analysis/fine tuning done on an classic '83 Ski Nautique. Do you guys have any recommendations or where to start? Thank you again for all your help! Dave ------------- Ski Nautiques deserve a second chance...... |
Posted By: Donald80SN
Date Posted: May-02-2018 at 11:36am
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Start you tuning with getting your timing dialed in. Someone will jump in with the proper timing number. Many here on this site will go with a slightly higher number than PCM states with great results . 10 or 11 degrees comes to mind, but I could be wrong. I do not remember numbers well. ------------- 1980 Ski Nautique SOLD Back to Cypress Gardens 2002 Sport Nautique, GT-40, FCT2, Cover Sports, Tower Bimini, Inc., Wet Sounds Audio System, Star Gazer Wake Edition S. 1968 Ski Nautique, Project. |
Posted By: 8122pbrainard
Date Posted: May-02-2018 at 11:41am
Dave, It's NOT a gap you want to measure. It's the parallelism of the coupling faces that shouldn't be more than .003" out from side to side top to bottom. ------------- /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: Webster
Date Posted: May-02-2018 at 11:46am
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Thanks Donald. Timing is good at 10 BTDC. Quick additional question: Where should the Orange alternator wire run? There are two orange wires. One is the Alternator and the other runs to the breaker for the ignition switch. Both are 10 gauge wires. Maybe spliced into the alternator wire? I would post a pic of the wiring configuration, but can't figure out how to post a pic to a "reply" post...... Dave ------------- Ski Nautiques deserve a second chance...... |
Posted By: Webster
Date Posted: May-02-2018 at 12:46pm
 So this is what I've been using for a "gauge" to configure the wiring. So far, not too accurate. ------------- Ski Nautiques deserve a second chance...... |
Posted By: shierh
Date Posted: May-02-2018 at 12:55pm
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I get 44 mph at 4500 on mine with the original prop re pitched from 13 square to 13-12. 1983 with standard engine and gear. My timing is at 10 or slightly higher for initial number, have not checked the advance numbers yet. I like the exterior of yours, nice job. Lets see the rest. |
Posted By: gt40KS
Date Posted: May-02-2018 at 1:39pm
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You said all new gauges ... which ones did you use? Again, unless you have a dual battery system and something is amiss there, it seems like it could only come down to a bad gauge. ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: KENO
Date Posted: May-02-2018 at 2:52pm
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Joe The quote is for you to read He answered the question already [QUOTE=Webster] Yes, the alternator is a marine alt. It's a Sierra International gauge called Sahara. /QUOTE] It probably looks a lot like this  He wired the gauge wrong and that's why it pegs. Dave your wiring diagram is for an ammeter not a voltmeter. You can most likely leave the Orange wire unhooked and tape/cap the end of it. It depends how your rewiring job was done.. |
Posted By: KENO
Date Posted: May-02-2018 at 3:07pm
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Here's a wiring diagram showing the flowpath from the alternator to the solenoid to the ammeter you don't have anymore. The ammeter originally had a 10 gauge red wire going to the ignition switch Batt terminal and the orange 10 gauge wire from the alternator. If the red wire is still there, hook them together. You may have gotten rid of that wire when you rewired things though, otherwise if you disconnect and tape it and the battery charges, you're all set. Hard to explain and maybe confusing to read this, but look at the diagram. 
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Posted By: Webster
Date Posted: May-02-2018 at 5:23pm
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Pete, so the couplings matched up perfectly. The ridge on the outside of one, matched with the inside of the other coupler along with the bolts. However, I was watching this youtube video of this guy using a feeler gauge to measure the gap between the couplers, or at least I thought. So it's no problem having a .005 or so gap between the couplers on one side? Top, left and bottom......no gap in-between. Right side had about .005 gap between couplers and couplers themselves matched up perfectly. I should be good there right? KENO, so the volt gauge only measures the amount of volts in the battery, but doesn't measure the voltage coming out of the alternator? OR if it does measure the volts being generated by the alternator, how is it measuring the volts if the orange alternator wire is hooked to the battery terminal of the ignition switch or taped off? I thought of hooking the orange wire up to the "i" terminal along with the purple wire on the volt gauge. That would be a mistake then? I still have the red wire going to the bat terminal of the ignition switch, This is very helpful, thank you both!! ------------- Ski Nautiques deserve a second chance...... |
Posted By: 8122pbrainard
Date Posted: May-02-2018 at 5:36pm
Dave, The actual thickness of the feeler gauge used doesn't matter. Again, it's the difference top to bottom side to side checking for parallelism of the coupling faces. IE:, you can use a .010 gauge at one point but if you get .007 or .013 opposite to the .010, you are at the max .003 out of parallel. It sounds like you are getting .005 on one side and .000 on the other, so you are out by .005 and alignment is needed. Also, keep in mind that alignment starts at the strut. BTW, which you tube video were you watching? To answer your question to Ken, the volt meter is indicating system volts. Less some slight resistance with wiring and connections, you should get the same readings wherever you connect the volt meter. ------------- /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: Webster
Date Posted: May-02-2018 at 6:03pm
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The parallel of both sides and top and bottom, I get it now. Thanks. I now should have the Volt gauge problem solved too. Thanks. The Youtube video looked to be a few years back. An older man with longer blond hair was outside sitting in a trailered Nautique, using a dowel rod and other wooden parts to demonstrate aligning the prop with the transmission. Looked like some kind of summer get together with a fairly large family like crowd...... It was very informative. ------------- Ski Nautiques deserve a second chance...... |
Posted By: 8122pbrainard
Date Posted: May-02-2018 at 6:08pm
Dave, I'll have to look for that video and watch it to make sure he knows what he's talking about.  ------------- /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: KENO
Date Posted: May-02-2018 at 9:46pm
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Dave Since you still have the red wire on the ignition switch batt terminal your solution would be to hook the orange wire to that. This just completes the circuit around the ammeter that isn't there anymore. Then hook up the voltmeter as mentioned previously. |
Posted By: Webster
Date Posted: May-03-2018 at 9:09am
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Would love to hear your input on the video PETE. KENO, the red wire actually runs to the fuse, then jumped to the bat terminal on the ignition switch. But that's the same thing right? So, I'll hook the orange wire to the bat terminal on ign switch, correct? AND thank you again for walking me through the Volt meter wiring. Every time I've been out testing for tweaks, etc., I kept wondering if the battery was going to blow up on me...... lol, Dave ------------- Ski Nautiques deserve a second chance...... |
Posted By: KENO
Date Posted: May-03-2018 at 9:36am
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That would work and putting a fuse in that orange line the same size as the one in the red line would be a good idea Or........just tape the end of the orange wire and everything should work just as it does now. since the way you had it wired the orange really didn't supply anything or do anything other than mess up the voltmeter indication. The more I think about it, I'd say tape it first and see how things are just in case you have any other wiring "oddities" under there with the rewiring job. |
Posted By: MelliLewis
Date Posted: October-12-2020 at 11:35am
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Hello...I have a few digital multimeters, and the battery is putting out 12.7V. The savaging engine framework is absolutely isolated. I tried the checks when completely detached from the vessel, direct to the battery. The measure pegs out whether or not it's snared to the S or the I, with the ground associated. I had a go at interfacing the S to the positive and the I to the negative, and turned around, and literally nothing occurred. I associated the G to the + and the S and I to the - , and the volt meter just went down rather than up. https://onlinequote.7pcb.com/" rel="nofollow - pcb quote
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