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84 Mariner 90hp Bogging Down

M

muskrat787

New member
I have a 1984 Mariner 90 hp that cuts out when I try to throttle up. Carbs have been rebuilt, all fuel line on the motor has been changed to barrier hose, the fuel pump has been rebuilt , the rectifier has been replaced and I am using a brand new portable fuel tank. The bulb stays hard through any running. Compression on all six cylinders is 135-140.
I can throttle up in neutral with no issues but under load the motor cuts out immediately upon throttle up. No hesitation, no lag. As soon as I throw the throttle forward from idle the motor starts bogging down. Can't get more than 1500 to 1800 rpms max.
Any ideas would be greatly appreciated as I would like to try to resolve the problem before winter really sets in.
Thanks in advance for any suggestions.
George.
 
Tried adjusting the carbs and no luck. So I took my timing light for a boat ride. All cylinders fire fine at idle. Checked each cylinder one at a time during throttle up. All cylinders checked ok EXCEPT #3. Every time I went to full throttle #3 would stop firing. So I took the wires off of #3 coil and #2 coil and switched them including the plug wires. Still had problem with #3 losing fire at throttle up. I have already changed the switch box so what could be causing this? Stator? Trigger?
Thanks,
George.
 
Replaced the trigger but it did not fix the problem. So I had seen that rectifiers can cause weird problems. Hadn't looked at that because I changed it back in the spring. Since I still had #3 losing fire at WOT I figured what the hell, it's worth a shot. So I disconnected the rectifier and the problem went away. Motor ran like a champ. So what now? Stator or rectifier?
 
As noted in my last post I already changed the rectifier in the spring and it ohms out as still being ok.
Should I still try a new rectifier.
 
Ran the motor today with the tach disconnected and the stator hooked up. Ran horrible so I can assume that the tach is not the problem. Disconnected the stator from the rectifier again and ran fine. Looks to me like the stator is my culprit.
 
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