merc 50/4cyl/2 strk-no spark

[fishhead54]

thanks 4 the help...have a key, mtr cranks real good...still no spark, disconnected mercury switch, still no spark, get a faint light from white wire coming out of cdi,just do not want to replace it if not necessary, any help to test it? thnks again,mark

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

More info. What is the year and serial number of your motor? Do you have ignition driver? Trigger with 4 coils?

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

THE MOTOR SERIAL STARTS WITH 372, FROM THE 70'S i BELIEVE, THERE DO NOT SEEM TO BE COILS ANYWHERE,HAS A TRIIGGER(DISTRUBUTOR RIGHT?), AND A COIL(ONLY ONE WIRE LEADING TO TRIGGER/DISTR.<br />i DID NOT OPEN THE BOW THE CENTER WIRE FROM TRIGGER GOES INTO, NOT SURE IF i SHOULD DO THAT<br /><br />THNKS RICKSRSTER

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

You are positive it is a spark issue? <br />1) Make sure all wire connections are clean and tight.<br />2) Tell me, do you have a rectangular shaped box with a red wire, blue wire, white wire, black wire and a green wire? The red, blue and white would go to the ignition driver. the Black and green would go to the ignition coil.

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

Oh yea, plus a brown and an orange wire conntected with the blue wire.

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

i HAVE TEH RECTANGLE BOX, FROM TOP TO BOTTOM, RED POST,BLUE,WHITE,GREEN...IN THAT ORDER.<br />RED GETS A RED WIRE, BLUE GETS A SALMON COLORED WIRE,A BLUE ONE,AND A BROWN. WHITE GETS A WHITE W/BLACK STRIPE, GREEN GET A GREEN, AND THERE IS A GROUNS SCREW ONJ THE BOTTOM ALSO. bOUGHT IT FROM A GUY, SAID IT RAN LAST YEAR, SO FAR...NO LUCK FOR ME.BUT...TRYING, BEING CAREFUL TO LOG EVERYTHING IF i DISSASSEMBLE ANYTHING.

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

CHECKED ALL THE CONNECTION, ALL SEEM CLEAN AND SNUG, WIRES GO AS U SAY

 

[Laddies]

Re: merc 50/4cyl/2 strk-no spark

You have a thunderbolt driver ign. the mag is just what it looks like the there are to coils in it that trigger the switch box (they can be tested with a ohm meter) and the bottom part is a distibuter that sends the spark to the right cyls. the remainder of the system needs to be cked with a DVA

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

ok, going out to get an ohm meter and some other stuff. procedure for testing?, looking for what reading? do not have the manual yet, it's in the mail. Yes, it is a thunderbolt ignition. Upon inspecting, the salmon colored wire is in bad shape, going to get wire to replace it and see if it helps, but I'll be back with ohm meter soon. thanks laddie and ricksrster.

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

That salmon colored wire is what stops the motor by shorting out the blue to ground. If that salmon wire grounds out, your motor will not run. When you get the meter, disconnect the salmon wire. Place one lead from ohm meter on the salmon wire and one on ground. With the key off there should be continuity. With the key on there should be no continuity.

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

The brown goes to a mercury switch that shuts off the motor when it is tilted. make sure that wire is good also.

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

did all the tests...as u say, read out correctly, still nothing, cranks great, too bad that's not enough rpms to get it going though. any more help...appreciated, getting ready to fold and take it to a mechanic soon, hope I can fix it myself, it's not just the money factor, it's the knowledge to fix it myself I am after, thanks to all, mark

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

ok, i disconnected the salmon wire from the harness and now i have spark, and strong it seems

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

OK then. we're narrowing it down. You said that the salmon wire is in bad shape. Is the insulation cracked? Unplug the harness that goes to your control in the boat. Now put one lead of the ohm meter on the Salmon wire you disconnected and the other lead to ground. It shoild be an open circuit. If it shows continuity, the wire is shorting out. It is bad. Are the other wires around the motor in good shape. If it is just the salmon wire that looks bad you can cut out the bad spot and splice in good wire. <br /> If the wire sows good, leave the harness unplugged. Disconnect your battery. Turn the key to on. Here is a picture. Put one lead of the ohm meter in the salmon hole in plug and other lead in the black hole. Should be open, nocontinuity.<br /> To make sure my picture isn't upside down, test with on lead in yellow and one in red with key on. Should show continuity. No continuity with key off. <br /> If the salmon wire shows continuity to black with the key on, Either the harness or the switch is shorting.<br />

 

[fishhead54]

Re: merc 50/4cyl/2 strk-no spark

ok...found the break in the wiring...replaced,resoldered,and heat shrank...all good electrical. Now...no fuel. This motor was purchased from a storage auction, sat with gas in it, and person that sold it to me let it sit some more, so, thinking I should re-build the carbs, kits seem real cheap, aroound 15 dollars each. anything about re-building them? Something I should look out for? Seeing as now it is a fuel problem, I will first check the lines, then the pump, then the carb. By the way, is there a fuel filter on this or is it an internal screen system on the carbs?

 

[ricksrster]

Re: merc 50/4cyl/2 strk-no spark

Definitely you want to do the carbs, fuel pump, and the water pump in the lower unit. Also drain the lower unit gear oil and check for water and metal. Refill with new Gear oil that is rcommended for out boards. Toss the old gas and get new.