|
ContinuousWave Whaler Moderated Discussion Areas ContinuousWave: Small Boat Electrical Outboard Engine Tachometer: 1999 Yamaha Two-cycle Engine
|
Author | Topic: Outboard Engine Tachometer: 1999 Yamaha Two-cycle Engine |
Binkster |
posted 12-07-2014 11:00 AM ET (US)
I just installed a new Yamaha binnicle shifter, a new wiring harness, and a new key start with harness, all coupled to a 1999 C60 Yamaha 60-HP two-cycle outboard engine on my 15-footer. Next, I would like to add a tachometer. There are four unused wires coming off the key start harness: red, green, yellow, and black. I have a four-cycle engine tachometer. I'm assuming the difference between a two-cycle and cour-cycle engine tachometer only the poles, which are changeable. [The tachometer on hand] also has sender, ground, ignition, and light connections. Can I use this tachometer? Or, do I need a dedicated two-cycle engine tachometer? And, how would I wire [the tachometer on hand to the Yamaha engine]? rich |
jimh |
posted 12-07-2014 12:02 PM ET (US)
On the tachometer gauge you have on hand, the wiring for the 12-Volt supply voltage, the 12-Volt common, and the Lamp Illumination circuit should be the same as on any outboard engine tachometer. There is little concern for those circuits and where to connect them. The only real concern is for the connection to the SENDER circuit. On a two-cycle outboard engine the usual source for the TACHOMETER SENDER signal is from the rectifier in the engine' s battery charging circuit. The connection is usually made to a point in the rectifier that delivers a half-wave rectification of the alternator coil output. As you are aware, the number of poles in the alternator, the number of magnets in the flywheel, and the wiring arrangement of them determines the ratio of the pulsating DC output to engine rotation speed, and the typical tachometer has a calibration control to match the dial calibration to a particular number of poles. In Yamaha wiring harnesses, the conductors are color coded according to the scheme I show at http://continuouswave.com/whaler/reference/wireColorCode.html#Yam According to that wiring scheme, the insulation color GREEN is used for tachometer signals. Usually with a Yamaha outboard engine the owner's manual provides an electrical schematic diagram that identifies all the major components, the wiring colors, and the signal functions. Consult that diagram to verify the circuits and wire colors. The wiring diagram in the owner's manual should clearly show the wiring harness and the four circuits you have left over. If the function of the conductors is not clearly identified, you can trace the circuit and deduce the function from its connection point. |
jimh |
posted 12-07-2014 12:03 PM ET (US)
I cannot address your question, "will the tachometer I have work?" You should ask a knowledgeable Yamaha service department person about that. |
jimh |
posted 12-07-2014 12:09 PM ET (US)
If you do not have the owner's manual for a 1999 Yamaha 90-HP, you can get an electronic copy. Visit my REFERENCE page on how to obtain electronic copies of outboard engine owner's manuals at http://continuouswave.com/whaler/reference/ownersManuals.html Follow the link I give there for Yamaha. At the Yamaha resource, locate the manual you need. I believe the manual you need can be found at http://www.yamaha-motor.com/assets/service/manuals/1999/ lit-18626-03-35_916.pdf Unexpectedly, it appears that in that publication no information is provided on the tachometer, nor is there a wiring schematic diagram. Most unfortunate! There was such a diagram in my 1987 Yamaha engine manual. |
Binkster |
posted 12-08-2014 01:21 PM ET (US)
Thank you jimh for the color code schedule, and your input. Electrical/electronic stuff is my weak point. I'll take the 4 stroke tach out of the equation and use the 2 stroke tach that presently sits in my antique runabout and see if I can make that work. If money were no object, I would probably buy a plug-in Yamaha tach, and just plug it into the new harness. rich |
jimh |
posted 12-08-2014 02:28 PM ET (US)
I really don't know if the tachometer you have on hand will work or not. You should get advice from someone with more familiarity with the tachometer you have on hand before you decide to discard it. |
alfa |
posted 12-09-2014 03:11 AM ET (US)
Hi Rich--using a 4 stroke tach with a 2 stroke engine: maybe the tach will show twice rev's. Have a try.--Alain |
saumon |
posted 12-09-2014 04:38 AM ET (US)
The GREEN wire coming from the wiring harness goes to the SEND input on the tachometer. The tachometer should be set to 6 poles for a C60 3-cylinder engone. |
jimh |
posted 12-09-2014 09:56 AM ET (US)
I spent some time using GOOGLE to search for images of a Yamaha outboard wiring diagram for a C90, but found nothing. If anyone has a copy of the wiring diagram for a Yamaha C90 outboard engine, perhaps you could make a scan of it and send it to me. I will be pleased to post it here for future reference. |
saumon |
posted 12-09-2014 12:16 PM ET (US)
If you're talking about the C60 (and not the C90), here's the wiring diagram. https://www.pdfhost.net/index.php?Action=Download& File=6b0a8e2c7cf863860536b74963ac2fa8 |
jimh |
posted 12-09-2014 12:33 PM ET (US)
Many thanks for that PDF document showing the wiring for a C60. In Yamaha lexicon, the "Lighting Coil" is the source of the battery charging current. The coil that Yamaha calls the "Charging Coil" is not used for battery charging; it is part of the electronic spark generation for the engine spark plugs. You can see that from the LIGHTING COIL, the circuit runs to the RECTIFIER/REGULATOR. The output of the RECTIFIER/REGULATOR is on three conductors: RED = 12-Volt positive to charge battery The signal on the GREEN conductor is a series of DC pulses. The frequency of the pulses varies with the speed of rotation of the engine flywheel. The tachometer is a frequency counter that scales the pulse frequency to engine RPM and displays it to the operator. |
saumon |
posted 12-09-2014 07:43 PM ET (US)
I'm be no mean electrical expert but, thinking about this, there sould also be a testing method to determine which wire at the remote control send the pulse, using a digital multimeter that can read frequencies, right? They can be bought for around $12 from ebay ( http:/ / www. ebay. com/ itm/ Mini-VICTOR-VC921-3-3-4-DMM-Multimeter-Poc ket-Digital-Multimeter-Frequency-lcd-k-/ 291223878318 ) and, let's say at idle an engine run around 1000 rpm, that's 16.7 Hertz (cycle per second). Giving the fact that the tachometer set on 6 poles divide the number of pulses by 6 to give the right rpm, I guess the measured frequency at the sending wire should be around 100 Hertz for an engine running 1000 rpm at idle and, at 700 rpm, it woulb be 70 Hertz. jimh, is this right? |
jimh |
posted 12-09-2014 11:44 PM ET (US)
It sounds right to me. Actually confirming it with a frequency meter would be even more interesting. I don't think any of my DMM's can measure frequency. |
Binkster |
posted 12-10-2014 11:52 AM ET (US)
If that's a fact then my 4 cycle tach won't be accurate when used on my 2 cycle outboard even when set to 6 poles. Can it damage anything in any way to try it? rich |
saumon |
posted 12-10-2014 03:31 PM ET (US)
rich, I don't think there's 4-stroke or 2-stroke tachometers. Yours may be labeled like that but, as long as it has the # of poles settings, it's the same for both. Have a look at this chart from Faria: http://faria-instruments.com/site_manuals/IS0086S.pdf . The same tachometers can be used for 2-stroke and 4-stroke. So, to answer your question, no, it can't damage anything and will even read correctly, as long as it have the right settings. What is, exactly, the brand and model of that "4-cycle" tachometer you have? Is this one designed for marine outboard applications? |
Binkster |
posted 12-10-2014 04:00 PM ET (US)
The tach was used on a '07 Honda 50. Only markings on the tach that might be a brand name is CE 50703-203/09 It also says 4 cycle gas--neg. side mof coil O/B W/alt--al;ternator The alternator is now set for 2 poles. rich |
jimh |
posted 12-10-2014 11:52 PM ET (US)
The alpha-numeric string with "CE" as part is probably some imprimatur of the CE Mark. It is a European certification mark. See http://ec.europa.eu/enterprise/policies/single-market-goods/cemarking/ about-ce-marking/index_en.htm It is not a brand name. Since outboard motors are more or less universally designed to run from 12-Volt batteries, you can expect that a tachometer for an outboard engine is expecting the tachomoter pulses to be in the 0-Volt to 12-Volt range. (Actually, the pulses are slightly negative, as I recall, an artifact of the rectifier.) So there ought to not be much difference between a "four-cycle" tachometer and a "two-cycle" tachometer regarding the voltage of the tachometer signal. I suppose some engine maker might have an odd way to generate the tachometer pulse and its voltage might be different, but, from what I have seen, outboard engines do not tend to push technology very hard, at least not older two-cycle engines. That leaves the only difference likely to be the calibration settings for converting the frequency pulses to RPM reading. Usually a universal-tachometer will have a wide range of settings available, from say two to six, for calibration. Again, I cannot tell you anything about how the tachometer you have on hand is going to work. You will have to tell us. |
Binkster |
posted 12-12-2014 01:43 PM ET (US)
jimh, I think from what I have learned from this thread I will hook up the 4 cycle tach and see if it will read the RPMs of my '99 Yamaha C 60. However I won't be able to start the engine to check for a week. Will check back in with the answer then. rich |
Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.