6-71 naturals

[Gina Marie]

The engines on a viking 40 have these engines with 2500 hours when are they do for rebuilds. Are these good engines my friend is looking at these.

 

[SKYCHENEY]

671N's are about as good as they get. I have seen many with over 20,000 hours on them and still going.

 

[luckydave215]

Those engines in commercial use (230 hp) routinely see 75-100,000 hours. Yacht engines aren't operated in a way to give service like that, even if the power rating is as low. Still, even when typically mistreated in a yacht, 6-71n's last a long time.

 

[spartonboat1]

Post was unclear...are they in fact due for a rebuild? What is the basis for that, although 2,500 would be the expected range, due to disuse, more than much running. If a true N and not turbo charged, rebuild could range from kits only (pistons, rings, cyls), or include bearings, and the roots blowers.

Survey could range from start and run, get the cyls compression tested, up to a full blown Williams Diesel $3K survey. At min, cyls compression and view cyl walls via the inspection ports. If they run, how is the oil pressure warming up and at 1,100 when warm. The oil pressure relief valve is set for 50#'s, so should be able to get at or near that.

Also, if oil not changed recently, could request oil survey.

 

[SeaEric]

Probably best to look them over well before purchase. They will usually do everything they are supposed to do, even if they do need rebuild. Plus they will do one extra thing- smoke a lot.