2003 mercury 75hp

[dowannar]

I have a 2003 75hp Mercury 2 stroke. It ran fine yesterday, today it wouldnt crank. There is no power at the key switch, no gages work, and lost control of power trim at all 3 switches. Motor will turn over when I jump solinoid, but wont start. 20 amp. fuse above solinoid is good. Is there any other fuses for motor? Help.

 

[Maxz695]

Re: 2003 mercury 75hp

try unplugging the pigtail and spray some lube on the connections as corrosion sometimes makes them lose contact. Check the engine grounds well

 

[dowannar]

Re: 2003 mercury 75hp

try unplugging the pigtail and spay some lube on the connections as corrosion sometimes makes them lose contact. Check the engine grounds well[/QUOT

Ran power to front up/down power trim switch and was able to trim motor up and down. Do I have a nuetral switch in the trottle lever that would cause motor not to start?

 

[Maxz695]

Re: 2003 mercury 75hp

You might I don,t know what kind of throttle your using but if you have an overboard saftey lanyard kill switch with the plastic key it may (The key be missing or worn down) Not allowing the switch to disconnect ground kill to the engine. Pull the switch out some and check for spark or temporarilly disconnect the wires to it. Dis regaurd the last post that would only stop fire not the starter. When you jumped the solenoid did you cross A) The two big terminals (Incorrect way) or B) the positive lead to the starter and the yellow wire (Correct way)

 

[Maxz695]

Re: 2003 mercury 75hp

You need a meter to see if you have current through the yellow red stripe or yellow black stripe not sure which (When turning the key) but one goes to the choke soleniod and the other to the starter solenoid. If you have no current [Meter black to ground and red Pos to the yellow wire]. check the ground at the ignition switch.

 

[dowannar]

Re: 2003 mercury 75hp

Jumped yellow/ red tracer from solenoid to red positive from battery and it turned over

 

[Maxz695]

Re: 2003 mercury 75hp

that means the soleniod is in good shape now the problem lies in the harness or key switch. Again test the power through the harness to the yellow red lead from the keyswitch Key switch turned to start position) you should have power. Did you try disconnecting the pigtail at the engine fuse yet and repluging it back in? Be sure all grounds are hooked up. Check al the dash fuses. Also try clicking the key switch with the throttle in several positions to F and R but do not try to get the engine running. This is just to see if the saftey neutral shifter switch may be bad.

 

[dowannar]

Re: 2003 mercury 75hp

that means the soleniod is in good shape now the problem lies in the harness or key switch. Again test the power through the harness to the yellow red lead from the keyswitch Key switch turned to start position) you should have power. Did you try disconnecting the pigtail at the engine fuse yet and repluging it back in? Be sure all grounds are hooked up. Check al the dash fuses. Also try clicking the key switch with the throttle in several positions to F and R but do not try to get the engine running. This is just to see if the saftey neutral shifter switch may be bad.

I have a 6 terminal switch. I have no power, all terminals show continuity to ground.

 

[Maxz695]

Re: 2003 mercury 75hp

The current to the key switch is the red wire hooked to the solenoid terminal. You will have to trace that to the keyswitch and see if it has 12 V it should be live to the fuse then it goes into the key switch or a power on off switch. This is the first thig I would check at this point. Then move on to other fuses and wiring in the dash. Is this a dash key switch, or a control box key switch? In any case there should be a fuse at the lead to the keyswitch.

 

[Maxz695]

Re: 2003 mercury 75hp

Reverting back to the fuse at the engine [ Physically remove the fuse re insert or replace it] The plug must be firmly inserted to make contact with the fuse. It may have corrosion stopping the connection or simply not pushed far enough together.

 

[dowannar]

Re: 2003 mercury 75hp

I disconnected the lead from solenoid to starter, reconnected red wires to solenoid that were with starter wire then jumpedred and yellow wire to bottom of solenoid terminal from battery and that gave me power fromyellow and red wire to switch, verifying power to switch. The power trim now works. But motor wont turn over through switch. How do I get to neutral switch in shifter?

 

[Maxz695]

Re: 2003 mercury 75hp

If there is a neutral switch there should be a plug from the throttle you can disconnect eliminating it your TT switch may also be in the shifter and you can temporarilly disconnect that as well if your not sure which is for a neutral kill switch. If the switch is the problem this will remove it and the key switch should then work. Please read back as my other posts have added information. I,m starting to think the ingnition switch may be bad but keep testing before replacing it. If there is power to the switch but no power to the solenoid via Yellow red stripe at the solinoid it tends to show a faulty ingnition switch or a break in the wire from key switch to solenoid Yellow red stripe. You can try to jump the red positive at the key switch to the yellow red strpie and see if the starter engages. If it does the key switch is shot. If it doesn,t then there is something between the fuse on the engine and the positive to the key switch that isn,t making the connection.

 

[dowannar]

Re: 2003 mercury 75hp

On the top terminal of solenoid, should I have just one wire going to starter and all other connected to bottom terminal of solenoid, which would give me constant 12v power?

 

[Maxz695]

Re: 2003 mercury 75hp

I,m not sure which type solenoid your using so here are both types View attachment 180157 View attachment 180160 The yellow red stripe goes to the small terminal to engage the starter when the key is turned to the start position. There is a mistake in pic 1 the red positive key switch wire goes to the battery side not the starter side as it has no current until engaged by the solenoid. The second picture is a 1979 70 HP starter solenoid with wire adaptation orangewire (ADDED) indicated as yellow red replaced wire.

 

[dowannar]

Re: 2003 mercury 75hp

neither of these are like my motor. Would you have a wiring diagram for the 75hp mercury 2 stroke?

 

[Maxz695]

Re: 2003 mercury 75hp

No Carlhome (Gerry) may be able to post it for you. Again did you remove the fuse at the motor and replace it and make sure the plug was in real tight to make a connection? Can you post a picture of your solenoid please. The red fuse wire goes to a big terminal along with the battery positive terminal. The starter wire alone goes to the other Big terminal there would be no power to the key switch if the red fused wire is on the starter wire side. The yellow red goes to the little terminal marked S For sender from the key switch

 

[Maxz695]

Re: 2003 mercury 75hp

Bump ^^^^^^ You need to swap the smaller fused red wire to the battery positive cable side of the solenoid. If you hold the key in the start position and have power to the yellow red striped wire to the sender but disconnected then the solenoid is NG. The yellow red striped wire will not have current in the on run position only the start posistion and must be held there when testing it.

 

[dowannar]

Re: 2003 mercury 75hp

Where do the wires I'm pointing to land?

 

[Maxz695]

Re: 2003 mercury 75hp

View attachment 180165 I would assume the other wire goes to the batt positive post as well trace it to find out where it goes to. Follow insturction for testing the yellow red when the key is in the start position for current. If there is current then the solenoid is more than likely NG. Remember the yellow red stripped wire wil not have current in the on run key position only in the key START position.

 

[Maxz695]

Re: 2003 mercury 75hp

yes The key switch needs a constant straight connection from the battery terminal. As there is no current at the starter terminal until the coper washer in the solenoid raises from the sender to make contact between both the Positve and starter wire.