One of my boats has an old 8-71 and it aint running right.

We did a job off shore where we had approx 18 hours stand by, we bumped in the seas for that time in idle. After that when I would go to full power it would smoke black more than usual and with clatter a lot more. (May be a missin cylinder) I changed the fuel filters and fixed the problem. Now the problem seems to be back but only at operating temp (filters clean still)

Any ideas?

 

mate i think i would start with lookin at the rack set and valve's and injectors, re-set them all and see what happens maybe throw a set of inj's in it and re-set inj's, valves, gov and rack.
hope you get the problem sorted mate

 

Is there excessive or more than normal oil dripping from the air box drain tubes? Sometimes excessive idling will allow oil from the roots blower, if the seals are worn, to build up in the air box creating a richer mixture situation for awhile. If this is the problem, be careful that it does run away. You may also want to check the air filter.
Good luck.

 

18hrs at idle????? That's about the worst thing to do to an 8V. Better off at WOT for 18 hrs.
Does it just clatter and rattle for a few minutes then clear up?

 

I agree. Thats definitely not a good thing to do with a Detroit. It would be 10 times better for it if you were running it wide open that whole time, that's the way they like it. We have a 4-71 generator, a 6-71 direct driving an old crusher, and an 8v-71 in an asphalt reclaimer. The only time they are ever idling is when they are warming up (governor on the 4-71 is wide open from start) and we haven't rebuilt any of them since we've owned them.

 

When I first started trucking, way back last century, I was told to slam my finger in the door, before I left the yard. Why? I asked. Because the proper way to run a Detroit is as if you're mad at it! Run it as hard as you can, it'll last forever.
That was back when they were 2 stroke, with a blower on top.
Can't do that today.

 

run the **** outta them and they stay happy. you might need to minor the engine just because of the extremely long idle period probally coked the **** outta the ports and such.

 

Those guys have it right on, that ol girl is probably coked up bad.

 

10-4, we let our twin 8v71TA's idle for about 3 hours once, and when we pegged the throttles to go back up to cruising speed they just ROLLED THE COAL. Upon further inspection both turbos had locked up with soot and ****... cant really kill them though

 

Might be a dumb question, but has anyone thought of, or tried running a small water/methanol injection system to help keep the ports and turbo clean. Might help when you have to idle for a long period of time.