View Full Version : Mercruiser 165 wiring

04-10-2006, 03:18 PM
"I got a mercruiser 165 straight six inboard. All of the wires behind the gauges and the ignition swich are disconnected. I wired the red ignition wire to a larger red lead coming from the back of the boat and a yellow wire with a red stripe to the solonoid and i am getting a click at the solonoid, but there is a white wire coming from the ignition that is not connected. If the click is there are the wires hooked up right or do i need to do something different because the engine still won't start, just a click. What is the minimum wiring i can do to see if the engine will turn over. Also if i straight wire the positive side of the battery to the positive side of the coil should the engine start, and is it bad for the coil?"

04-10-2006, 03:35 PM
"What are the other wire colors? Most boats use purple for ignition and this goes through the safety switch if there is one. You have points and there should be a resistor going into the coil primary- it may be outside or inside the coil, depending on the coil itself. If you want a diagram, maybe a service manual would be a good idea, since it's not going to be the last time you'll use it. It will be worse for the points than the coil but it will start.

You may want to check the starter itself. If the battery + is on one leg of the solenoid and you use a test lead of some kind, go from the battery + to the smaller terminals and see if it wants to crank. If there are three terminals, it should crank UNLESS you have the battery + on the wrong terminal, in which case it should have started cranking immediately. You could have a bad solenoid, too.

It sounds like you found the right crank terminal on the solenoid-if you have a multi-meter, check the other large terminal for voltage when you turn the key.

There is a bypass tab on the ignition switch, which is for the odd wire going to the coil +. This is there because the starter causes a sufficient voltage drop that the resistor would keep the coil from developing enough voltage to fire. It may be the white wire. There should also be a grey wire at the coil, which is the wire going to the tach input. Blue wires are for the dash lights. Blacks are the grounds, which should all be marked on the back of the guages. Look at the fuel sender for the color of that wire, too."

04-10-2006, 04:05 PM
"I just changed the solenoid, so i know that it is good, the wire colors coming out of the ignition are red, white and yellow with red stripe they are marked "I", "B" and "S" respectivley on the starter. Should one of those wires go to the Coil?"

04-10-2006, 04:15 PM
"If you don't have a multi-meter (digital) I would get one and become good at using it. The I wire goes to the coil and if theres no fourth tab on the ign switch, it probably bypasses the coil when you crank the motor.

What did the solenoid diagram show?

What kind of boat is it? They're not all wired the same way. Yo may want to contact the boat builder and give them the hull ID number so they can look it up."

04-10-2006, 04:39 PM
"The solenoid has four posts, two large and two small. The wires are: Large red and tan, and small black and yellow/redstripe. I have a digital multi meter and i am going to check what you told me before. Thanks."