1994 Mercury 90hp outboard 3cyl 2 stroke

N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Hello All,
I just finished working on my 1981 17ft Beachcraft. I am new to boatin but not new to mechanics. I have several questions.
1)My Mercury control has cables seperate from the main cables that go to the motor. I fugured out that the black and grey are the tach gauge. What do the other cables go to?

2)The tack gauge has settings behind it. These settings, from my research, have something to do with the type of charge or poles my motor has. Is my motor 12? Is that the setting I should have it on?

3)Being a 2 stroke, I have mixed the fuel and oil at 50:1. Is this correct? Has anyone seen better performance from changing the mixture a little?
Thanks for the help.
Eddie
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,762
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

By cables do you mean what are individual wires for in the "harness" that run between the control box and the engine?
If you have a 12 pole alternator you set the switch on the tach to 6P (pulses) unless the settings on the tach actually refer to 12 poles. The difference is that a 12 POLE alternator produces 6 PULSES on the tach line.

The motor needs a 50:1 mix. And while you might get a very slight bit of extra rpm from a high-tech oil like Amzoil the extra cost is simply not worth it. Any oil with a TCW-III rating is fine. DO NOT use oil intended for AIR-COOLED engines as it not for outboards and is not TCW-III rated.
 
N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

Thank you very much.
There are 4 cables plus the black and grey cables. These cables dont seem to connect to the motor. I dont see where they would connect inside the motor. I did connect the main harness inside the motor. But these cables are individual cables coming straight out of the control box. I saw in a drawing that showed some of these cables going to the instrument cluster. Im not sure where or for what they are used.
How can I find out if it is a 12 pole alternator?
 
N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

Does this engine have a thermostat?

The wires I need to connect are purple, pink/blue stripe. Where would they go?

Thanks for the tip on the oil.
 
D

Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,078
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

That motor has oil injection and you do not premix unless the oil pump has been removed or somehow disabled. If you premix you could be running 25:1.

Yes the motor has a thermostat located on the back near the top.
 
N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

Dave1027 said:
That motor has oil injection and you do not premix unless the oil pump has been removed or somehow disabled. If you premix you could be running 25:1.

Yes the motor has a thermostat located on the back near the top.
Click to expand...

It had the oil mix system removed. I have to premix it now. How would i know if the motor gets hot? Is the a sensor?
 
D

Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,078
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

There is a water temp sensor that should be hooked to a temp gauge.
 
N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

Dave1027 said:
There is a water temp sensor that should be hooked to a temp gauge.
Click to expand...

Hello,
I dont see any temp gauge or sensor. I have a purple cable, a pink with blue stripe cable, a light brown cable and a darkbrown with white stripe cable that are not hooked up from my control handle. Are one of these the cable for the temp sensor? Sorry for the questions? Just trying to learn.
Thanks
Eddie
 
D

Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,078
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

It's the Tan (light brown) wire in my book.
 
N

newboy12

Cadet
Joined
Nov 29, 2011
Messages
10
Re: 1994 Mercury 90hp outboard 3cyl 2 stroke

Thanks. I will hook it up to the motor. What do the other cables do? I have looked through the forums with no luck.
Thanks again
Eddie
 
You must log in or register to reply here.
Top