What is the cause of this ? (photos) 25 HP soot problem

[kodibass]

So the motor shook back and forth badly' so I found the upper center motor mount was broke, as well as one side motor mount, its a mod# J25TELCSA 25hp johnson, So does all the black soot mean the base to LU gasket is bad? or where el's would it have come from? I remember a thread from the Machinist covering this condition but cannot find it, The power head ran ok other than the shaking, but it does not seem to shift well you have to kinda pass neutral and go to forward to get it back to neutral from reverse, I do not know the history of the motor it was a freebee. I don't know if its worth trying to fix or not, but I do like the fact that it has both pull start & electric.

 

[Chinewalker]

Re: What is the cause of this ? (photos) 25 HP soot problem

That's typical grease & grunge that accumulates on the inaccessible area under the belly pan. The opening in the pan under the carb allows the odd fuel drip to stick through. The gas evaporates, leaving oil, which over time also loses some of its content through evaporation, becoming a sticky goo. That area never gets wiped off, rinsed off, etc. so it just accumulates. Your motor is 30+ years old - lot of time to accumulate it.

 

[F_R]

Re: What is the cause of this ? (photos) 25 HP soot problem

Yeah, mine looks like that too. Been meaning to get around to washing it. Someday.