1982 Mercury 50 HP Thunderbolt Ignition

[matthewch88]

My 50HP is about to give me grey hairs. When I first got the boat, it would run down the lake then get hot and go to idle speed and wouldn't rev up. So I had the carbs cleaned to no success. Then it quit firing on two cylinders so I changed the power pack, fixed my firing but not my first problem. I then also changed the water pump and found bits of old impeller vanes (the top of the block reached 197 degrees). Still no fix to my problem. I finally pulled the powerhead off and cleaned all the water ports and passages (removing 4 more impeller vanes). Still no fix but my max temp on the block is now 143 degrees at the crank just behind the carbs. Then I did some research to my voltage coming from the stator and going to the power pack then to the coils, keep in mind that I have equal spark on all cylinders. I got my reading with the motor cold, which was 2.75 volts to each coil at idle. Then we ran it down the lake and it began acting up so I checked my volts. I had 1.2 volts to each coil now at idle with 85 volts from the stator. We also found the rectifier housing had bubbled where it had been so hot previously. We changed the rectifier and all four spark plugs. I keep looking for a stator, but can't find a stator like mine. My flywheel has glued on magnets and my stator is coated, 4 wire and 9 amp with a part # 398-5454A21. The only thing they make now is an uncoated stator which is not operational with my flywheel. Does anyone know where else I can look and does it sound like I've trouble shot the engine correctly? Is there anything else I need to trouble shoot?

 

[plazmore]

I accidently purchased a coated one thru amazon...from a third party...was for a three cylinder where mine was a four...it was a sierra 18-5865...fit perfect, but was missing a wire...I was lucky and was able to return it, and ordered the right one...the new one is as you described...no covering...apparently the stator, trigger and rectifier wiring will be toasted when the motor is overheated...I have replaced two out of three...the trigger comes in a couple days...also thru amazon...I recommend you buy a cdi product, but they might not have the one you need...mine is a mariner four cyclinder...50hp...1982...my original stator was a25...good luck!

 

[rollincoal02]

Well hopefully I can help I have the same stator and just replaced mine thinking that was the problem but it wasn't im guessing switchbox. Where did you hear an open stator won't work with your flywheel? Your stator has 6 wires not four. It has blue, blue/white, red, red/white, and the two yellows that go to the rectifier. You can find our stator everywhere if you want the exact one it will be about $350-$400 because it has been super-seeded so many times but I just bought a CDI electronics brand stator for $140 and it works fine with my flywheel. I also have a four cylinder 50hp.

 

[rollincoal02]

Well hopefully I can help I have the same stator and just replaced mine thinking that was the problem but it wasn't im guessing switchbox. Where did you hear an open stator won't work with your flywheel? Your stator has 6 wires not four. It has blue, blue/white, red, red/white, and the two yellows that go to the rectifier. You can find our stator everywhere if you want the exact one it will be about $350-$400 because it has been super-seeded so many times but I just bought a CDI electronics brand stator for $140 and it works fine with my flywheel. I also have a four cylinder 50hp.

 

[plazmore]

I have heard the same...new style stator doesn't work with glued in magnets...