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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16206
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have a 1994 Yamaha 225, I recently sent the engine off

Customer Question

I have a 1994 Yamaha 225, I recently sent the engine off for a complete overhaul. While putting it back together, I got the two wiring harnesses mixed up, the one for the tachometer and the one for the oil tank inside the baot. After discovering this, I switched them and now the Tachometer will not work at all, nothing on it works and it has power going to it
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Marine Mechanic should know?
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Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

Hello my name is ***** ***** am I speaking with?

Which tachometer do you have installed in the boat, is it a Yamaha tach or another brand?

What color wires do you have hooked up to the back of the tach?

What is the model number on the engine?

Do you have a voltmeter, and do you know how to take voltage measurements?

Are you near the engine now and ready to work?

Customer: replied 1 year ago.
It is a Yamaha Tachometer that came with the engine. I am not by the boat currently. The Yamaha Tach is digital and also has the trim level on right side. At the bottom is four warning light
Customer: replied 1 year ago.
I do have and understand how to take voltage readings
Customer: replied 1 year ago.
if you give me your phone number I can text you a picture of the front of the Tachometer
Customer: replied 1 year ago.
my name is*****(###) ###-####
Expert:  Jason replied 1 year ago.

Hi Russell,

What is the model number on the engine?

Customer: replied 1 year ago.
I do not have that with me--it is a 1994 225 HP
Expert:  Jason replied 1 year ago.

I would need the exact model number to continue. Without it I dont' know which manual to pull. There are no time limits here, do you want to reply back one you have the model number?

Customer: replied 1 year ago.
I just found the Model Number 225 TLRS
Code 6K7L
S/N 351686
Expert:  Jason replied 1 year ago.

Got it. Hook your meter up to the battery, start the engine up, and bring the rpms up to about 1500. What does the voltage read?

Customer: replied 1 year ago.
I'm not near the boat right now and starting it and running it anytime soon would be a problem as it's in my garage.
Expert:  Jason replied 1 year ago.

You have to be able to run the engine in order to test this. What kinds of questions did you have?

Customer: replied 1 year ago.
The tach is completely dead and I know there is 12 volts to the Tach, could I have burnt it up when I reversed the plug in the engine compartment, i.e.: I hooked the plug for the oil tank to the plug for the Tacometer and when I did this it made the alarm continue to sound until I realized what I did and then reversed the wires.
Expert:  Jason replied 1 year ago.

The tach gets it's signal from the ECM, which in turn gets its signal from the voltage regulator. The voltage regulator is a portion of the battery charging system. So what you want to do is see if the battery is charging or not. If it's not, then the voltage regulator is likely dead. If it is charging, then there is likely a short in the tach output circuit board inside of the ECM. And at that point you would either get a new ECM. Or, get a basic cheapo tachometer and hook it up to the voltage regulator. does that make sense?

Expert:  Jason replied 1 year ago.

Did you have any further questions on the issue?

Expert:  Jason replied 1 year ago.

I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you

Expert:  Jason replied 1 year ago.

Hi. It looks like you read my answer without replying back or leaving a rating. Please keep in mind the website has charged you to speak with me, but they will not credit me for helping you until you put through a rating for me. If you had a further question on the issue by all means feel free to ask. If not, please kindly select a rating for my service.

Thanks again and happy boating!


Customer: replied 1 year ago.
Ok, I am at the boat now it's in my garage,
Here are the wires
A blue wire and black wire for light
A green/red and a green/ white (one plug)
Grey, pink,orange,black/white (one plug)
BlackThe yellow wire has 12 volts when key is on
The black wire is a good ground
The back light works when key is onNeither the trim indicator nor tach reading comes on when ignition switch is on.
Expert:  Jason replied 1 year ago.

I'm sorry I don't understand you. Why are you telling me wiring colors?

Customer: replied 1 year ago.
Well I thought by telling you what the wiring colors were it would help you in what I'm dealing with along with if they had any power !!!
Remember, I'm the dumbass that is paying for this service and your the "mechanic" !!!!
Expert:  Jason replied 1 year ago.

But I don't understand what you are trying to do??? Are you trying to hook the tach up? I thought you said you already had it hooked up?

Customer: replied 1 year ago.
You know, you ask me what color wires were on the back of the Tach, so I provided you this information and now your asking why I gave you the color of the wires !!!
Once again, the only thing on the Tach that is working is the back light.
The yellow wire is hot with the key on and it has a good ground. The trim level part of the gauge is also not working.