Noobie needs help identifying 50hp motor/ Spark issues..

bgathy402

Cadet
Joined
Sep 14, 2014
Messages
11
Hello iboats members,
I recently bought a 1981 Bass Tracker III that the owner put a Mercury outboard motor on, the serial number on the transom plate is 0A982085. Said it ran good and recently had some work performed on it.
All I can tell is that its an 80s(?) 3 cylinder motor and the cover says its a 50HP.

Previous owner had a new CDI Stator/Trigger installed on the motor. I bought the boat and the first time I took it out it ran badly and then eventually came out of it and ran great so I assumed it would be good to go. The next time I took it out it ran badly for 10 minutes and then ran good again until I shut it off for about 5 minutes then it ran poorly the rest of the time, just wouldnt go very fast like it had a missing cylinder.

When I pulled it out of the water I took it home and put a spark tester on it, it confirmed it had a miss on 1 cylinder, based on research I bought a CDI switch box and it fired right up running on all 3 cylinders and charging at about 13.4 volts. I took it out to test and it ran great again.. For a while... on the way back to the dock I was going at full throttle and all the sudden it just shut off like the kill switch had been activated.. Pulled the cover and now I have no spark on any cylinder with the new CDI switch box. When I brought it home I installed the old switchbox which used to have 2 good working cylinders and I still have no spark on any cylinder.

I disconnected the black/yellow wire at the switch box which is supposed to be the kill wire and I still have nothing. Now im worried that the motor has an underlying condtition that is ruining the ignition components, most likely why the previous owner had the stator/trigger replaced.

Ideas would be greatly appreciated!

Thanks
 

Jamescenterconsole

Seaman Apprentice
Joined
Mar 31, 2013
Messages
40
Try disconnecting the two yellow wires comeing from the stator to the rectifer. Check for spark, if you have it the rectifier is bad. Check the battery also it needs a full charge. Clean all the terminals at the battery and the motor. You need 250 cranking RPMs for good spark. Thats all I go,t there are some on here that know way more than I do.
 

bgathy402

Cadet
Joined
Sep 14, 2014
Messages
11
Thanks James, I am almost thinking I have a bad battery.. I am going to buy a new one tommorow and retest. I am thinking even if I did somehow get a bad switchbox from CDI the boat should have still had spark on the old switchbox that fired 2 cylinders. I did quite a bit of dissassembly and testing of the wiring and didnt find anything, I also found a section on troubleshooting from CDI that I will use if the battery dont fix my problem.

Also I read on one of the engine Identification sites that if the serial number start with 0 you should drop it, That would make it a 1986 motor. Can anyone confirm?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,307
your basstracker orriginally had a merc on it back in 81, it could have been ordered with a 40, 50, or 60hp. since the motor is an 86, it has been replaced

sounds like something is taking out the CDI
 

bgathy402

Cadet
Joined
Sep 14, 2014
Messages
11
Right, the boat came with a 40hp Johnson I believe the previous owner said when he bought it and it was a pile so he ditched it for this merc. What could be taking out the electrical ignition components? It has a CDI stator/Trigger and CDI trigger box. I put in a new battery today and still got nothing. Also I noticed that the starter drive gear wasnt disengaging from the flywheel. I put a coat of oil on the shaft though and that fixed it. Could the starter gear not disengaging cause electrical damage and how?

I tried testing the CDI components with the troubleshooting page they provide and I didnt find anything I tested to nearly be in any of thier ohm specs. I dont believe that all the sudden I have a bad stator and trigger at the same time.

On further inspection I did find one of the pins in the engine harness connector pushed in so I think Im in for a new harness at least. Probably going to have to buy a manual too.
 

enginepower

Petty Officer 1st Class
Joined
Jul 5, 2014
Messages
260
Right, the boat came with a 40hp Johnson I believe the previous owner said when he bought it and it was a pile so he ditched it for this merc. What could be taking out the electrical ignition components? It has a CDI stator/Trigger and CDI trigger box. I put in a new battery today and still got nothing. Also I noticed that the starter drive gear wasnt disengaging from the flywheel. I put a coat of oil on the shaft though and that fixed it. Could the starter gear not disengaging cause electrical damage and how?

I tried testing the CDI components with the troubleshooting page they provide and I didnt find anything I tested to nearly be in any of thier ohm specs. I dont believe that all the sudden I have a bad stator and trigger at the same time.

On further inspection I did find one of the pins in the engine harness connector pushed in so I think Im in for a new harness at least. Probably going to have to buy a manual too.

CDI has an awesome troubleshoot guide. I'm hoping you did your ohm test with components disconnected. CDI uses a different winding technique so their stator ohm specs will be different than OEM so make sure to go by their spec readings.
 

bgathy402

Cadet
Joined
Sep 14, 2014
Messages
11
Hey guys, I got a SELOC manual for the boat. I did the thunderbolt stator test they had listed. The red-Red white resistance checks were in spec, the resistance test between blue and blue/white called for minimum of 5.7 ohms, mine made 4.xx ohms. The other test said to check resistance of the red wire to groud and the blue wire to ground, Neither call for continuity with powerhead ground. The red one did not have continuity as it was supposed to but the blue wire did have continuity, like 3 ohms. Im assuming the high speed coil shorted out. Even though the stator and trigger were relatively new I ordered new CDI trigger/stator and rectifier to go with my new cdi switchbox, that way I know everything was new when I owned it.
 

bgathy402

Cadet
Joined
Sep 14, 2014
Messages
11
Hey guys, figured Id post an update to this. i hated searching the forums and never finding out if peoples solutions fixed thier problems.

So I ended up purchasing all this new stuff from CDI
Battery
Stator
Trigger
Rectifier
Switchbox

Hooked it all up and it runs pretty well now. I am fairly certain the trigger was the issue. The glue on the top of it looked like it got hot and melted as there was some bubbling in it.

The previous owner said he had replaced the trigger and stator before I bought it. Im wondering if there was an underlying issue with the old switchbox being bad that made the old trigger die prematurely.
 
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