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1973 mercury 1500 L6 no spark

D

Dwayne1969

Member
Can the rectifier cause no spark? Rectifier is testing bad and I’m just trying to get ideas on what else it could be. Timing marks are lined up and compression is good.
 
No the rectifier charges the battery only - if the battery is below 9v it might not spark or if the white and red wires on the switchbox aren't energized with 12v, make sure the connections on the battery are right.wiringhipower767778.jpgIs this a new to you motor?
You might have a damaged trigger use these steps to checkTrigger-shooting_Page_2.jpg
 
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Quicksilver said:
No the rectifier charges the battery only - if the battery is below 9v it might not spark or if the white and red wires on the switchbox aren't energized with 12v, make sure the connections on the battery are right.View attachment 23304Is this a new to you motor?
You might have a damaged trigger use these steps to checkView attachment 23311
Click to expand...
It is new to me and I will try and test it this evening.
I purchased this boat super cheap and am hoping to get it running. I found several shorted wires and have already replaced the engine wiring harness and am ordering the rectifier as well.
 
I purchased this boat & trailer (1978 VIP ski boat) for $800. boat is in very good shape, kept in boat storage most of its life, seller inherited the boat and used it on lake until two years ago. He tried to hook up a radio and somehow shorted out the wiring harness. he rewired the harness(very messy) and could not get spark afterwards. I have replaced the engine wiring harness, new lube in lower unit, traced all wiring from controls to the engine harness. checked timing marks(according to service manual) and traced all engine wires to make sure they are in the right place. I am currently trying to troubleshoot anything else and all suggestions are appreciated.
Merc 1500 150 Srl number 3754922 (not original engine for boat).
 
.."He tried to hook up a radio and somehow shorted out the wiring harness."

Argh! I suspect the trigger coil in the distributor may be burnt. You need to check it with an ohm meter. If the circuits read open it's shot.

Jeff
 
I'm back; been dormant for the winter; am no mechanic but had a no spark condition on my '92 Merc 40 4 cylinder 2 stroke last season; finally figured out via testing it per the shop manual that the stator was shot; bought a new one made by CDI Electronics; fired right up. As for why the stator went bad; totally my bad; made a mistake when charging the battery in the spring while still connected to the engine; inadvertently bumped the charger switch from 12 volts to 24 volts; got lazy, I usually disconnect the battery from an engine before charging it. Yes Virginia you can mess up an electrical system if you try.
 
faztbullet said:
You cannot test this trigger with a ohm meter...
Click to expand...
Could have sworn I tested the trigger assembly when I had a spark problem; dusted off my shop manual published by Brunswick Co. and looked at page 2A-2 'Electrical and Ignition'. There is a 'Trigger Assembly Test' using a VOA meter: 1. Disconnect all trigger leads from switch boxes. 2. Between the brown trigger lead and the white/black trigger lead, the Ohms should be 700-1000 (mine was at 841). 3. Between the white trigger lead and violet trigger lead, the Ohms should be 700-1000 (mine was at 839). Resistance specs are for a room temp engine. Also disconnected the battery from the engine. Maybe there is another test.
 
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Those are instructions for ADI ignitions this trigger doesn't have white/black or violet leads, If you would look at post Nr. 2 the answers are there for a quick check and he doesn't say the trigger is defective!
 
The only kill circuits are : 12V switched on/off at switchbox with key and the "mercury filled"switch attached to brwn trigger wire to switchbox. Do the testing posted.
 
Ok, so checked everything according to the CDI electronics outboard troubleshooting guide pg 82. 4. Coil is sparking going into the distributor no spark from plug wires. 6. No voltage 7 No voltage on green wire.
 
Have you removed the dist cap to see if the rotor is there, it's molded onto the shaft so don't try to pull it off! There should be a carbon rod in the middle of the cap that contacts the rotor - I don't if you can measure the voltage on the green wire but if the coil is sparking then it must be getting voltage.
 
Thanks Quicksilver!
This could be the problem! I noticed this was different from an automotive cap but thought it was just because it was a marine engine. There is a hole directly to the rotor where the high tension wire from the coil attaches! This is supposed to be a new cap. Is this correct or can someone send me a pic of what the inside of the distributor cap on this engine should look like?
 
There is a hole that the carbon contact sits in, it is spring loaded to create contact with the rotor. Is the timing belt connected when you're doing these tests?
It is like an auto cap except for the screw-in wire connections.cap-and-spring.jpg
 
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