lots o back smoke

[roberthowell]

1984 perkins 3 cyl 30 hp puts out lots of black smoke when transmission engaged neutral none

[model 10]

When the fuel pump goes bonkers that can happen but did you check your exhaust elbow?

[exMaggieDrum]

A big load can do that too. I'd check the prop shaft and tranny too to see if anything is binding.

[DefinitelyMe]

Black smoke = incomplete combustion. Check air filter first as it's easy to do. Excessive load will have the same effect. Does the prop have lots of growth on it? Is something binding on the shaft? (check by turning it by hand. it should be easy to do (with the engine in neutral!)). After that you're looking at fuel issues. Governor, fuel pumps, fuel quality, blocked filter, sludge in the fuel, worn injectors etc.

disclaimer: i'm not a mechanic!