yamaha old 8hp smoke and exhaust from wrong plase?

[Tropax]

hi i have a old yamaha 8hp ca 1972 mob
i godt it started fine after some tlc and everything seemed to be fine butt after a few runs on the boat the cooling strems / smokes , the streem is mutch weeker butt stronger almost fine on 1/3 throtle.
and the exhaust dosent come out the normal exhaust hole on the bottom.
it comes from the lowerpart on the body swirl!

also i see two grease plugs on the houseing what oil/grease shud i use?

se photo

please can anyone help me?
i cant find the manual for this engin!

[robert graham]

I doubt the exhaust is a problem, most any grease will do for those fittings, but of course Marine grease would be the most recommended. Nice old motor!