Desperate - Please Help with Merc ignition problem

[dstuard]

I rebuilt the fuel pump and replaced some hoses on my 83 115HP Merc. Also put in a new gas tank. Took it out to test it and acted like I was getting no fire. What could I have possibly done to make this happen? Could it have something to do with the the wiring on the new sending unit or checking the guage by grounding the sending unit?

 

[12Footer]

Re: Desperate - Please Help with Merc ignition problem

You werked on the fuel pump, so I would squirt some mix into the carb throat, and see if it sputters.<br />If you're sure it has zero spark, check the kill circuit lanyard, emergency,ignition and mercury tilt switches.<br />The best place to start is at the switchbox black with yellow stripe wire...Remove it and fuel source, a couple squirts of fuel, disconnected from the fuel line (because if it regains ignition,you will be unable to shut it down),and try it.If it has spark with the kill circuit disconnected, check every switch mentioned above and the black with yellow stripe wire harness for short to ground.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

There waa no way to disconnect the wire from the kill swithch so I cut it to see. Still no fire so I cut the wire off the other side and still no fire. However I determined that both wires were grounded. Should this be the case? Could I have a bad ignition switch? The black wire with the yellow coming from the ignition switch is also grounded with the key off and with the key on. Please help before I do something bad.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Also the green wires on the coils are grounded. Should they be? They are grounded even when the wiring harness is unplugged. Also my black with gold stripe is not grounded on both sides when it is unplugged.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Where are the mercury tilt swithches and the switch box? I cut the wires on the emergency kill switch.

 

[Hooty]

Re: Desperate - Please Help with Merc ignition problem

On most o/b's black is ground. I don't know what the green wires on the coils are but if they are windings, they also go to ground. U-needa shop manual. Check the lower left hand corner of this page for a generic manual or see your friendly Merc dealer for a real manual.<br /><br />c/6<br /><br />Hooty

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

I have a manual but had a hard time finding this stuff. I need to know where the tilt swithch is and the emergency. I believe that I have it narrowed down to a ground problem and I believe it is from the motor side of the harness. What do the tilt switches do?

 

[12Footer]

Re: Desperate - Please Help with Merc ignition problem

Did you find the switchbox?<br />If so, disconnect the black with yellow stripe wire at it's terminal. To shut the spark off on your engine, this black wire with yellow stripe is connected (by a switch of one kind or another) to the black, (or ground).<br />If that don't give you spark, you have other problems.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

I guess I am not too smart. If the switch box is not the one with the ignition switch than I can not find it. I have tried seperating the black wire with the yellow stripe from the kill swithch and the ignition switch. I am about at the end of my rope here. Is there a switch box besides the control box?

 

[Trent]

Re: Desperate - Please Help with Merc ignition problem

If its truly a 1983 model it has two switchboxes. They are mounted to the powerhead and look like this.........<br /><br />

<br /><br />Check this link out..<br /><br /> web page

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Found the box and disconnected the black and yellow. Still no spark. What can I try next?

 

[Trent]

Re: Desperate - Please Help with Merc ignition problem

Disconnect the rectifier and see if she fires. Make sure your engine is turning over at "full cranking speed" If not she will not fire.<br /><br />Also remove the sparkplugs and then see if she fires.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Where is the rectifier Trent? Sorry for my stupidity and thanks for the help.

 

[Trent]

Re: Desperate - Please Help with Merc ignition problem

Its right near the switchbox. I think yours looks like this?<br /><br />

<br /><br />Also disconnect the mercury switch and see if she fires.. Hope this diagram will help?<br /><br /> Diagram

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Two of the wires that connect to it are pretty worn. The plastic is off the end and they are a bit corroded. Could this be my problem? I will disconnect and see. Stay tuned.

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Still no luck. I was able to blow the fuse and mess up the holder. I am feeling pretty good about it now. I have almost managed to fix all the stuff I messed up while trying to fix it. What would be my next step? Call a boat tech? I also managed to get my choke to stop working. I am going to need a shrink soon!

 

[NathanY]

Re: Desperate - Please Help with Merc ignition problem

Here is a wiring diagram for your motor. <br /><br /> http://www.maxrules.com/oldmercs/Wiring/1966ona/37.pdf

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Thanks for all the help fellas but I have packed it in. I am out of the boat business until I can buy a brand new one. Thanks again for all the help.

 

[Hooty]

Re: Desperate - Please Help with Merc ignition problem

dstuard,<br />Where do you live in Texas? If ya live close, I might could give ya a hand.<br /><br />c/6<br /><br />Hooty

 

[dstuard]

Re: Desperate - Please Help with Merc ignition problem

Hooty,<br /> I am in the Austin area but it might be worth a road trip if you are serious about helping. I have calmed back down today and I will be ready to troubleshoot a little more in a few days. If that does not work I might take you up on it.<br /><br />I have one more question. The yellow wires the go to the rectifier are badly worn. They look like a bad battery cable and the plastic is gone off them. Could this be my problem of not getting enough current through them?