We've had our 966 loader for several months and now the engine starts to dog down when under a heavy load. We changed the fuel filters and element, but it still does it. Could it be the fuel pump?
Did you check the little fuel strainer/ sediment bowl under the injection pump? Does your dash pressure gauge show fuel pressure? What series 966?
When it bogs down does it smoke really badly? If so it could be your turbo charger...
Firstly, have you actually verified the complaint? Assuming that you are not the operator and are just going by an operators opinion, when you changed the fuel filters did you test it yourself or did you give it back to the operator who made the initial complaint to determine if you had in fact fixed it? When you say under heavy load, do you mean when digging under heavy load or travelling for example driving into the face and stalling it, or both?
It's a 966A. Thanks for all the feed-back. We did check the fuel strainer. Now we suspect that it's an air leak, so we're checking that out. My brother and I are the operators. By "under heavy load" we mean lifting boulders. We have built a diamond wire saw and are cutting our marbled quartzite into table tops and counter tops. Have several people interested.