Anyone know what the Yamaha control unit is for?

vetteman80

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Mar 23, 2014
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Hello, I have just completed a basket case Ebbtide with a 7.4 454 and Yamaha sterndrive project. The boat is up and running, trims up and down and goes in and out of gear well. There is a small box that mounts to the rear of the left side exhaust riser or manifold, which has 4 wires with bullet connectors. It appears that the red is constant power, black ground, a brown and orange which go to the very lower part of the outdrive. I looked the part up in a parts schematic and is listed as a control unit, I was under the impression that it was responsible for spark timing or as a spark interrupter for shifting. I have unplugged it and have seen no change in any function. Does anyone know what it is for?
 

mudsliders

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Sep 9, 2013
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Re: Anyone know what the Yamaha control unit is for?

Pretty sure what you are refering to is the interface between the trim sender/limiter mounted in the gimbal housing (the wires you see coming from the outdrive) and the trim pump/trim relays.

Ray
 

vetteman80

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Joined
Mar 23, 2014
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2
Re: Anyone know what the Yamaha control unit is for?

Thanks for the reply, I guess the part is nothing too critical. I will see if my trim gauge will read or limit with the unit unplugged.
 

Capt Ken

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Joined
Jul 30, 2002
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2,269
Re: Anyone know what the Yamaha control unit is for?

Nope, is a cathode unit that connects to the block under the transom assembly.
 
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