visual spark test box

[averep]

Hello All, Was reading a post about checking spark on a 300xs and they had the wires hooked to a see thru box with 6 fake plugs that would show spark, can't find the post but want one of these boxes, any ideas on where to get one, Thanks for the info, John

[Hippie459MN]

Inline spark tester. Look that up on Amazon. I have about a dozen of them and helped me track down a bad coil on my 85hp merc on my kids Hydrostream. Would cut out when it got warm and put one on each cylinder, went out on the lake, and could see what one stopped firing when it got warm. It just goes inline of the wire and they work great for tracking down ignition issues.

[averep]

Thanks Hippie459MN, I want the 6 plug box to do spark ck , no plugs installed and motor not running, the old merc spark plate works but the box looks sealed where you don't have to worry about arch hitting you or something else while spinning motor over, etc. Bet them wires look nice firing at night, Thanks for the info, John

[averep]

Found the post by Stoker Boy in a post about a Mirage/260 and checking the timing, just need him to respond , Thanks in advance, John

[RogerH]

Here's pictures of a tester we put together several years ago to find / evaluate the better Merc Gen-4 switch boxes. This could be used to test any of the components in this particular setup. The key factor is the pressurized and visable "spark box". We actually found that a few of these gen-4 boxes would work (@ 125psi) up to 13K RPM. They were the exception, as several wouldn't even get ot 6K. Also found that the Merc boxes drew 5-7 amps @ 12v & 6K-7K RPM. (CDI's unit never exceeded 4A-5A @ 6K rpm) The "good" boxes were used in race motors by Kevin & Larry McAfee (Y-44). All of the Merc boxes would deteriorate over time and eventually changed all the motors to CDI units.

[Dave Strong]

CDI sell a nice one will do a V8.

Dave

[averep]

Thanks for the info, Stoker posted his as homemade but added the link for the cdi unit at less than $70, so gonna order one, never thought of putting pressure on the plugs but that really makes it tested under real conditions, very nice setup, the spark box seems a perfect addon to the JSRE timing dial indicator, Thanks John

[scott reierson]

Wow! Nice. That's serious dedication to the tower of power battery ignition system. Interesting to see the CDI units tested more efficient. Like the distributor spinning setup. Thanks for posting.

Here's pictures of a tester we put together several years ago to find / evaluate the better Merc Gen-4 switch boxes. This could be used to test any of the components in this particular setup. The key factor is the pressurized and visable "spark box". We actually found that a few of these gen-4 boxes would work (@ 125psi) up to 13K RPM. They were the exception, as several wouldn't even get ot 6K. Also found that the Merc boxes drew 5-7 amps @ 12v & 6K-7K RPM. (CDI's unit never exceeded 4A-5A @ 6K rpm) The "good" boxes were used in race motors by Kevin & Larry McAfee (Y-44). All of the Merc boxes would deteriorate over time and eventually changed all the motors to CDI units.

[InjectorService]

Thats a cool test box. We're you seeing a big difference in results from your test box to a regular spark tester set at 3/8" or more?

[Forkin' Crazy]

Thanks for the info, Stoker posted his as homemade but added the link for the cdi unit at less than $70, so gonna order one, never thought of putting pressure on the plugs but that really makes it tested under real conditions, very nice setup, the spark box seems a perfect addon to the JSRE timing dial indicator, Thanks John

I have the CDI unit as well. You can adjust the pins to put more of a load on the coil to simulate combustion pressure. I think I set mine at 7/16???