Merc classic 50 no start

Joined
Jun 4, 2017
Messages
12
So I’ve got a mid-late 80s 45hp “classic 50”. Last summer during an outing the throttle actuator piece broke resulting in no throttle control. Well I let the boat sit during the winter and figured it’s time to get it back up and running. Found the part I needed at a boat salvage yard and came home and installed it. Drained the gas tank, put fresh gas in it, hooked up the water hose and guess what. Turns over but won’t start. It’s getting fuel but no spark. I removed the black/yellow wire from the switchbox and checked for spark again.... nothing. Next step??? Any help would be appreciated. I’d like to get back on the water lol
 
Joined
Jun 4, 2017
Messages
12
The battery is bad so I was using a booster pack and jumper cables running off my car both at the same time so I figured it should have been enough to fire it off.?.?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,164
Get a good and load tested battery and try starting this motor.-----Very important to do this.
 
Joined
Jun 4, 2017
Messages
12
Just got back from advance auto. Took my main starting battery and both trolling motor batteries with me to be tested. All are no good (go figure). So I had them test the one in my truck (a 800CCA marine starting battery) and it tested good. Got here and put my truck battery in the boat and hook everything up that I’ve undone. No spark. Unhook black/yellow wire from switchbox and no spark. Unhook both yellow wires from the rectifier and still no spark. So I guess I need to ohm out the stator?? I just don’t get how it was running when I put it up for the winter and now it won’t run.?.? How does a part like a stator go bad just from sitting??
 
Joined
Jun 4, 2017
Messages
12
Ok guys. Found the CDI troubleshoot guide for my ignition system. So far what I’ve done goes right along with what they are saying. So apparently I have the ‘RED’ stator on my motor. Coming out from under the flywheel are two yellow wires (going to the rectifier), a gen/wht and wht/grn wire that both go into a rectangular box that has a black ground wire coming out and a blue and blue/wht wire coming out. I do not have the special meter adapter to measure the voltages but was able to ohm it. CDI says something like 500-700ohm for grn/wht-wht/grn. I measured 698ohms. Then it says blue-blue/wht should be OL. Well I’ve measured 698ohms on those as well. So does this mean that rectangular box, that I’m guessing is part of the stator, is bad and is all that needs to be changed?? Please help me with this it’s driving me nuts!!! Oh forgot to add. The testing said nothing about ohming the yellow wires but I did anyway and measured .5ohm
 
Last edited:

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Could be a simple connection. I had a merc pin connector that made connection based on temperature. it took me forever to find it but the pins were hollow and can be spread for better contact. Once I spread the pins the problem was solved. Did you eyeball the stator for dark discoloring or burns?
 
Joined
Jun 4, 2017
Messages
12
The main engine harness plug under the cowl was quite gunked up with old di-electric grease. I cleaned it up and the male terminals have slits in them so I had slightly spread them all open to get a tighter connection. Still nothing. I have not pulled the flywheel yet to inspect under it. But what I was getting at was CDI says the blue wires should show open circuit when ohmd. They are reading exactly the same as the green set of wires.
 
Joined
Jun 4, 2017
Messages
12
Haven’t had any time this week to mess with the motor but hoping to jump back on it Saturday. Does ANYONE have any clue what’s up with the ohm test results I did on the stator. Please I need some guidance!!!
 
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