Merc 175 flywheel confusion

[H20Rat]

So the backstory... I've got a merc 175 sportjet (its basically a v6 black max powerhead) Recently the +12v wire from the voltage regulator got hot enough to melt through the shrinkwrap and touched the yellow wire from the stator, basically destroying the stator at the same time. When I pulled the flywheel off, I noticed that my magnets were pretty much non-existent also, lots of pieces!

Fast forward to today. New merc flywheel, same part number (271-859348-C) and a new CDI stator. It runs unbelievably great for about 30 minutes, better than its ever ran. Then the high speed coil starts acting up, around 3000 rpm it spits and sputters. I manage to make it back to the dock, and notice the stator is smoking! Pull the flywheel off again, and the ignition coils on the stator are burnt. Even the nylon support straps on the coils are melted.

So as you can see from the pics, the flywheels aren't the same! I hadn't done a side-by-side comparison when I got the new one, but the magnets are substantially larger. Again, the part numbers are identical. From my research, it seems there might be a 40 amp and a 12 amp flywheel? I would have thought they would have had a different number? Also, anyone else agree with my assessment that the larger magnets might have cooked the stator?


Anyway, just looking for any advice!

 

[j_martin]

Re: Merc 175 flywheel confusion

Yep, you put a 40 amp flywheel over a 16 amp stator. Smoke is normal for that setup. No way the 40 amp wheel fits under a 16 amp cover.

Now you need the right flywheel and a fresh stator.

 

[Faztbullet]

Re: Merc 175 flywheel confusion

Ooops!!! J is correct and you need to get your money back on flywheel. Correct part # is 271-859238T13

 

[H20Rat]

Re: Merc 175 flywheel confusion

It was an ebay purchase, so back on ebay it goes! Still a little confused why the part numbers on the two are identical... (and yes, I've had 2 other people look at it just to make sure I'm not crosseyed! They are the same) Thanks for the part number though, its been a pain to track down! At least there are some out there that are halfway affordable...

 

[Faztbullet]

Re: Merc 175 flywheel confusion

If seller sold it as a SJ flywheel, they were wrong as thats a 40 amp outboard flywheel. The SJ 16amp flywheel is vented like the 40 amp but the 16amp outboard is non vented.

 

[j_martin]

Re: Merc 175 flywheel confusion

It can get expensive when you don't pay attention, which could by why you are too poor to pay attention.

but I digress,
I suspect any low height V6 flywheel (16A, 9A) will do fine, but the heavier magnets of the 40 amp fry the lesser electrics in a hurry. Used 16 A stators should be fairly easy to find.

 

[H20Rat]

Re: Merc 175 flywheel confusion

It can get expensive when you don't pay attention, which could by why you are too poor to pay attention.

??? part numbers matched... at least in theory, for all I knew the newer updated flywheel could have had weaker magnets. Large weaker magnets would have been the same as smaller rare-earth magnets. (in case you didn't know, rare earth magnets are becoming, well, rare! Most of the supply is in china, and they are now keeping most of it and not allowing exports)

So its not really a case of not paying attention, but mercury using the exact same part number on two vastly different parts.

 

[Faztbullet]

Re: Merc 175 flywheel confusion

The number you posted must be a casting number as it does not come up on the Mercury website. The difference in outboard flywheels are : 9 amp are approx 1" in depth, while the 16amp are approx 1 1/8" in depth.,that why part listing ask you to measure lamination thickness.