6v71 loss of power

[jaypullen]

Well I posted a while back and still cant figure this out I have a 1977 mc5c with a 6v71 it seems to have lose power and blows black smoke  Ive took off the air intake and ran it but it still does the same thing I took off the exsaust manifolds and started it to see if I had a wet port (dry) replaced the fuel filters not sure were to go from here I no its lost power because I was able to pull the altamont hill in 3 at 45-50 with 5 harleys in the bus and now empty I can get maybe 25-30 out of it Any good mecanics in the bay area that know these motors Im in san mateo ca Thanks Jason Pullen

[TomC]

If you have removed the air intake system and ran it with the blower open and still blows black smoke, either the blower is bad, you have a bad injector(s) or stuffed up exhaust system.  Good Luck, TomC

[buswarrior]

Critters built a nest in the muffler?

Unhook the exhaust plumbing anywhere that a clamp will come apart, the pipes can still be hanging there, just get a sufficient amount of space opened up to let lots of exhaust leak out to see if it makes a difference.

Most frustrating

happy coaching!
buswarrior

[jaypullen]

Critters built a nest in the muffler?

Unhook the exhaust plumbing anywhere that a clamp will come apart, the pipes can still be hanging there, just get a sufficient amount of space opened up to let lots of exhaust leak out to see if it makes a difference.

Most frustrating

happy coaching!
buswarrior
I pulled the exsaust manifolds off and started it to see if there was a wet port but they were all dry I pulled the intake hose off to see if that would help No luck Thanks

[robertglines1]

did your fuel milage go in the toilet? if so too much fuel..bad injector or pump.you seem to have covered the air end.check your oil level on stick is not growing.if so unused fuel is passing rings (fuel Annalise time)..not good could indicate poor compression...so keep plugging away and I hope it is not a high dollar problem..these thought are just where I would start looking and I am not professionally trained mechanic. Happy Bussing Bob