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Ive been dealing with this motor for about a month so please forgive the long post but here goes:
3 months ago i buy a 1981 thunderbolt bass boat that is a project for sure but has a reliable spirit 85 (which is a Suzuki DT85) on the back of it. I know it’s reliable because I took it out about 2 dozen times and the motor never gave me so much as a concern.
Then, one day I broke the key off in the ignition out on the water I was able to get it started with my knife and get back to the ramp. Obviously needed a new switch so I ordered one off amazon and wired it in. Upon completing the new switch installation I tried to start it, it cranked for 1 second and then I lost all power to the switch. I had blown my main fuse but didn’t realize it. I hooked a jump wire from the positive side of the battery to the “B” terminal on the ignition switch and it fired right up. I did this 3 times and it started all 3 times. Then I realized it was a blown fuse, replaced it and went to crank it and I cranked but wouldn’t start. I determined I had no spark on any of the 3 cylinders. I brought it to a mechanic so he could test the stator and store the engine while I rebuilt the transom (it was very soft, rotten plywood core). About a week later I pick up the motor and my guy says the stator ohms out fine and his bet is either a bad ground or bad power pack.
I get it home and go thru it for a bad ground. Find no evidence of a bad ground connection anywhere... HOWEVER, there’s a bolt inside of my remote controller that acts as a ground for the ignition switch and control cables that was disconnected. There’s no man overboard safety on this controller. It’s old and the previous owner removed it. Anyway, I fix the loose connection in the controller by running a wire from terminal “M” (the prong not the raised bolt hole) with a ring terminal around the bolt in the controller.
then I tried to start the motor. Bear in mind, that each time since the problem appeared I would try to start it and it would crank and crank endlessly without firing. This time, I turn key and the motor turns over a few times, then the spring in the key releases and goes back to run and I can hear the motor turn a few more times before it stops. It feels like it started in the key switch because the tension from turning to start is released but there’s no actual ignition. I try a few more times and the above repeats a couple times before the last time I tried it and I heard a HUGE pop like a gunshot out of the exhaust. I have not tried since hearing this backfire(I assume?) I mean I don’t even know whether to be encouraged or discouraged by this. Immediately after it happened I inspected the exhaust and there was a bit of smoke coming from it that faded quickly.
I should mention, I’ve put new plugs in. I have confirmed the wiring to the ignition coils isn’t incorrect and the plugs are in the correct cylinders. The last thing worth mentioning is the high tension lead between the ignition coil and cylinder two seems to have an issue as it just falls out of the coil every once in a while. I am replacing that next. Also am I correct in thinking that in order to experience (what I guess is a backfire) I have to have spark on at least one of the cylinders?
just wanted to check here before ordering a power pack. Any and all help is tremendously appreciated.
also sorry for making a new thread about this - but figured this would be more comprehensive explanation of what’s going on.