Force 70 hp questions.

[Theoutdoorsman]

I have no idea as to how to identify the correct model number on this outboard. These motors were notorious for fading motor plates as I understand. Hopefully someone can help correctly identify the model/year? The current identification plate is beyond legible.

Here are my problems:

1) I am having trouble starting this outboard. Apparently, the enrichment solenoid is bad. I can apply +12v to the lead on the solenoid, and there isn't any response from it. No clicking, no movement ... nothing. I can hold my hand over the carb throat while cranking, and she comes alive pretty quick, and runs like a top. Short of this cold-start issue, I'm fairly happy with it. Starts first crank after warming up. I need to replace that enrichment solenoid. Can anyone help with the part number?

2) Now, for the wiring question. There is a black wire coming off the starter solenoid. It is damaged from an apparent short in the system, probably from someone attempting to short out the solenoid to start the outboard at some point. I can repair that, no problem. My question is, there is a green wire w/white stripe coming out of the wiring harness that is not terminated. Nor can I find another wire from which it may have come disconnected. Can anyone tell me what the purpose of that lead is, and where it might need to be terminated? Perhaps, since everything is running properly, I may just need to tape it off? I'd still like to know its purpose though, if anyone can help.

 

[Faztbullet]

Make sure the nipple feeding primer from carb is not stopped up with debris

 

[markhodges78]

Also on top of the head there should be a quarter size plug with a number on It that would be the serial number

 

[Theoutdoorsman]

Also on top of the head there should be a quarter size plug with a number on It that would be the serial number

Forgot about the freeze plug. Thanks for the reminder!

 

[Theoutdoorsman]

Make sure the nipple feeding primer from carb is not stopped up with debris

Shouldn't the primer respond when voltage is applied?

 

[QBhoy]

Green and white is usually trim up wire. I think anyway

 

[roscoe]

Key components to identifying the year:

1 Switchbox with bullet connectors (not a pair of cd modules, or a terminal strip with screw connections )
A square Mercury fuel pump ( not an "8" shaped pump )
A fuel enricher.

If you have all of the above, you should have a 1994-95 model

If you have all above except the switchbox has screw terminals, its a 1993.

1995 was the last year for the 70 hp.
Mercury Force serial number ranges 1991 - 1999
OE000001 - OE065371 1991-1993
OE065372 - OE093699 1994
OE093700 - OE138599 1995
OE138600 - OE202999 1996
OE203000 - OE287999 1997
OE288000 - OE344999 1998
OE345000 - OE369299 1999

 

[jerryjerry05]

Force didn't always have a freeze plug.
Look on the starter for the year? if it hasn't been changed it should be on there.
ALso there might be a foundry stamp under the pack/coil assy. and under the bottom carb.
Round circle with the year in the center.
The T@T wires were/are solid blue(up)
and solid green (down)
A 12v test light is one of the best tools in your box.
To test the primer: unhook the tiny hose to the bowl on the carb. then supply 12v to the wire to the solenoid. It should shoot a bit of gas for each contact.
There's a rubber diaphragm in the primer that can rot and go bad.
If yours starts and runs when you hand choke it? then the primer might be good and the 12v to the primer isn't getting there (key switch or broken wire??)
Pushing the key in activates the primer but you need to push it again and again for more choke. Holding the key in only gives it one shot of fuel.
You also have to prime the motor with the squeeze ball for the system to work.

 

[Theoutdoorsman]

Green and white is usually trim up wire. I think anyway

Awesome! I just confirmed my up/down switch on my controls is working. Are those wires "supposed" to be tied in to a relay of sorts, or am I good to connect them directly to the trim pump? I have no idea the electrical current required to operate the pump, or whether those wires are of sufficient size to carry the load. Thanks!

 

[roscoe]

You need a wiring harness with 2 relays for the tilt.

 

[The Force power]

Awesome! I just confirmed my up/down switch on my controls is working. Are those wires "supposed" to be tied in to a relay of sorts, or am I good to connect them directly to the trim pump? I have no idea the electrical current required to operate the pump, or whether those wires are of sufficient size to carry the load. Thanks!

 

[The Force power]

View attachment 377772

 

[Theoutdoorsman]

View attachment 377772

Question now is, where can I pick up a reasonably priced trim relay harness (aftermarket or otherwise)? Thanks for the info!


Update:

I picked up a used primer solenoid on ebay, applied 12v to it, and verified it responded. I tested the original, and be damned if it didn't start responding again too. When 12v is applied after installation, it see/hear/feel no signs of "life" from either solenoid. Will have to investigate further when weather permits. Needless to say, I am still struggling to prime the fuel system as intended.

 

[racerone]

The primer is a valve that opens when 12 volts is applied.----It is a very misunderstood item.-----What were you expecting to see?

 

[The Force power]

I picked up a used primer solenoid on ebay, applied 12v to it, and verified it responded. I tested the original, and be damned if it didn't start responding again too. When 12v is applied after installation, it see/hear/feel no signs of "life" from either solenoid.

Check your ground(s) wires, if it worked on the bench; it should work on the motor.
I think you have a bad or no ground to the valve and/or the engine

 

[Theoutdoorsman]

A small amount of fuel entering the carb throat. Maybe feel the solenoid click. I don't know. I expect to see "something" though. Should I not?

 

[The Force power]

A small amount of fuel entering the carb throat. Maybe feel the solenoid click. I don't know. I expect to see "something" though. Should I not?

Bench-test; no power applied & blow on it = no air passing through - Power applied & blow on it = air passing through
Simple test, however the valve may?? have a flow direction??

 

[Theoutdoorsman]

Bench-test; no power applied & blow on it = no air passing through - Power applied & blow on it = air passing through
Simple test, however the valve may?? have a flow direction??

I have tried plumbing that valve in both directions, yes. The valve operates as I feel it should. It's either open, or it's closed. Makes no difference at all. Fuel will flow through the valve when 12v are applied. It will cease to flow when 12v are removed. Fuel will NOT flow through the fuel line when 12v are applied AND the exit end of the fuel line is above the float level in the carb bowl. Zero fuel will pass through the fuel line when that condition exists. Best I can figure is that the system is gravity fed. The nipple on the carb throat, where the fuel line from the enrichment solenoid connects, is located above the carb bowl. As a result, there is no "dumping of fuel" into the carb throat before cranking the outboard. I'm "assuming" the crank case pressure is supposed to pull fuel from the fuel enrichment system when 12v are applied to the enrichment valve, as the engine is cranked, for there is no "forcing of fuel" via that enrichment valve regardless of primer bulb pressure. Is my assumption correct?

 

[Theoutdoorsman]

The primer is a valve that opens when 12 volts is applied.----It is a very misunderstood item.-----What were you expecting to see?

A small amount of fuel entering the carb throat. Maybe feel the solenoid click. I don't know. I expect to see "something" though. Should I not?

 

[The Force power]

I have tried plumbing that valve in both directions, yes. The valve operates as I feel it should. It's either open, or it's closed. Makes no difference at all. Fuel will flow through the valve when 12v are applied. It will cease to flow when 12v are removed. Fuel will NOT flow through the fuel line when 12v are applied AND the exit end of the fuel line is above the float level in the carb bowl. Zero fuel will pass through the fuel line when that condition exists. Best I can figure is that the system is gravity fed. The nipple on the carb throat, where the fuel line from the enrichment solenoid connects, is located above the carb bowl. As a result, there is no "dumping of fuel" into the carb throat before cranking the outboard. I'm "assuming" the crank case pressure is supposed to pull fuel from the fuel enrichment system when 12v are applied to the enrichment valve, as the engine is cranked, for there is no "forcing of fuel" via that enrichment valve regardless of primer bulb pressure. Is my assumption correct?

IF my memory serve me correct....the fuel-line to the enrichment-valve was connected to the bowl?
This line would get filled/fuel flowing from the fuel pressure;
Initially by the primer bulb / followed by the fuel pump during the cranking /running of the engine