No RPM; Yamaha multifunction gauge

greebo208

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Joined
Jul 21, 2013
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Does anyone have a wiring diagram for the Yamaha multifunction gauge which explains why there is no rpm/tach value (remains at zero) until you are actually tilting/trimming DOWNWARDS (only). Either the remote throttle switch or the trailer switch make the rpm indicate, whilst the engine is moving.....[ F115 on 6M rib]
thanks for your help
 

greebo208

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Joined
Jul 21, 2013
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Re: No RPM; Yamaha multifunction gauge

Useful to have an answer posted
the answer is... there is no electrical link. I checked continuity in each wire of 10 core yamaha cable and found the tach send wire was broken. I can only assume that as the engine tilted the connection was temporarily made. It seemed unlikely that one wire out of ten could somehow break. Although I could run another feed from the ECU to the gauge ( or use the unused ( dark blue wire) the fix would be very crude and look bad at the engine end.
I decided the harness would have to be replaced and discovered there were ten bullet connections under the deck by the transom. Although wrapped, being exposed to salt water for 8? years you can imagine the condition of the bullets and the copper wire. I think the original problem was that the 703 remote was only supplied with 5M of cable so on a 6M rib an extension was required. The wiring of the multifunction gauge is actually quite straightforward. I think any electrical connections exposed to salt water are probably doomed....
 
Joined
Feb 17, 2012
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Re: No RPM; Yamaha multifunction gauge

thanks for posting your findings at least when the next person has the same problem your post will be a great starting point.
 

greebo208

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Jul 21, 2013
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Re: No RPM; Yamaha multifunction gauge

update 2
Rejoined the ten wires; tried to solder connections but the copper was too corroded to tin, even with strong flux, so had to clean wire and use crimps and protect with heat shrink;
Everything now worked but not convinced that connections under deck would be reliable in long term, which is quite useful when the F115 is the only way home other than paddles!
Bought a Yamaha 8M/26ft harness (perfect length) which has correct engine 10 pin but only the two sockets for 704 remote, so chopped them off and rejoined to bullets at 703. Now at least the cable harness is continuous under the deck and the connections are high up in the console, relatively dry.
End of story......?
 

99yam40

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Sep 7, 2008
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8,851
Re: No RPM; Yamaha multifunction gauge

not sure why you did not buy the correct harness, but it would have been the proper way to do it
 
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