1958 Mark 55 E 40hp, no spark.

[Porto]

Hello, I recently aquired a 1958 Mark 55 E 40 hp mercury outboard motor (ser# 1149942). The motor looks good and has great compression, but no spark. I don't have the ignition that plugs into the side of the motor. My question is do I need the ignition plugged in to get the motor to spark. If not, what is my next step in trouble shooting or solving my problem. Thanks.....

 

[Laddies]

Re: 1958 Mark 55 E 40hp, no spark.

No thats magneto ign,you might want to try unhooking the mercury switch from the mag to make sure it's not shorted, but it's peobably the pts

 

[Chinewalker]

Re: 1958 Mark 55 E 40hp, no spark.

HI Porto,<br /> Start by disconnecting the two yellow wires that run from the stator under the flywheel to the series of plates mounted to the belly pan. That's the rectifier (converts AC to DC current) and will burn out if you try to run the motor without the plug hooked in and motor hooked to a battery. Outside of that, the motor ought to run fine without the plug hooked up.<br /> Okay, now it's time to extricate the magneto from the mag tower. There are four bolts that hold the mag to the tower, plus a few linkages. Use a permanent marker or a punch to mark the position of the linkages so you get them back on in the right spots.<br /> Drop the mag and twist, turn, cuss until it comes out. Now, remove the bottom cap, gently remove the rotor, Clean all contacts, distributor tips, etc. with 320 or 400 grit sandpaper to remove any corrosion. Now remove the main cap. Clean the contact on the coil. Clean the points, gap them at .008". You can bench test it using a bench vise. Ground the main housing to the vice. Hold the coil contact about 1/2 inch from the vice and spin the magneto over - rotates clockwise looking down. You should get a spark to jump that 1/2-inch gap. Then go about reassembling the mag and do a second bench test to see if the distrubutor is working. Line up the plugs in the vice jaws and ground the mag body to the vice. Spin it over and you should get spark in all four plugs.<br /> Run Champion J6Cs gapped at .030". <br /> Check the timing belt for checking of the rubber.<br /> Great old motors - good luck!<br /> Manuals and parts available at oldmercs.com...<br />- Scott

 

[Porto]

Re: 1958 Mark 55 E 40hp, no spark.

Hello, I worked on this project last night. I couldn't find anywhere to unhook the two yellow wires except to disassemble the rectifier and remove them from it. I hope that was right. I was able to remove the mag, remove the caps and clean all the contacts, ect. I bench tested the coil contact like you said and I got the spark to jump about 1/8 of an inch, no further. I put everything back togther and pulled it over. I was unable to get the plugs to spark. Does this mean bad points or something else? Thank you......

 

[Chinewalker]

Re: 1958 Mark 55 E 40hp, no spark.

Hi Porto,<br /> I should have included a warning about the rectifier... It's what's called a "selenium" rectifier and it's got some pretty bad stuff in it. Most of the motors I've seen have had scissor connectors in the wires further up, usually covered by a a rubber sleeve. Gotta be careful with those old rectifiers...<br /> You should be able to bench test with the entire magneto together as I described in stage II of my description - saves installing it back on the motor to discover that you still don't have spark.<br /> One check - is the timing belt intact? It's at the top of the magneto tower, looped under the flywheel.<br /> If you've got spark with the cap & cover hosuing removed, then the points should be fine. I would suspect something with the rotor and cap. Make sure everything is clean. If something looks really worn or burned, consider replacing it. Not cheap as far as parts go, but sometimes good new ones turn up at well-established marinas who have something left on the dustier shelves in back...<br />- Scott

 

[123landrover0]

Re: 1958 Mark 55 E 40hp, no spark.

HI Porto,<br /> Start by disconnecting the two yellow wires that run from the stator under the flywheel to the series of plates mounted to the belly pan. That's the rectifier (converts AC to DC current) and will burn out if you try to run the motor without the plug hooked in and motor hooked to a battery. Outside of that, the motor ought to run fine without the plug hooked up.<br /> Okay, now it's time to extricate the magneto from the mag tower. There are four bolts that hold the mag to the tower, plus a few linkages. Use a permanent marker or a punch to mark the position of the linkages so you get them back on in the right spots.<br /> Drop the mag and twist, turn, cuss until it comes out. Now, remove the bottom cap, gently remove the rotor, Clean all contacts, distributor tips, etc. with 320 or 400 grit sandpaper to remove any corrosion. Now remove the main cap. Clean the contact on the coil. Clean the points, gap them at .008". You can bench test it using a bench vise. Ground the main housing to the vice. Hold the coil contact about 1/2 inch from the vice and spin the magneto over - rotates clockwise looking down. You should get a spark to jump that 1/2-inch gap. Then go about reassembling the mag and do a second bench test to see if the distrubutor is working. Line up the plugs in the vice jaws and ground the mag body to the vice. Spin it over and you should get spark in all four plugs.<br /> Run Champion J6Cs gapped at .030". <br /> Check the timing belt for checking of the rubber.<br /> Great old motors - good luck!<br /> Manuals and parts available at oldmercs.com...<br />- Scott

This info got me up and running , yes I know it’s an old post but I appreciate the help