From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Future Yamucha (ヤムチャ みらい, Yamucha Mirai; Literally meaning "Yamucha Future") is an alternate timeline counterpart of Yamucha. He is seen briefly in Dragon Ball Z: The History of Trunks and in "Ghosts from Tomorrow" in a flashback. He is shown outside of Future Son Goku's house as Goku died of the Heart Virus. He is later killed by Future Artificial Human No. 17, who breaks his neck with a swift kick after Yamucha attempts to attack him. He dies after Future Vegeta and before Future Tenshinhan.
Early life and death of Future Son Goku
Future Yamucha's future life was the exact same as his main timeline counterpart's life until the Trunks Saga. In August of 764 Age, Future Yamucha watched as Future Son Goku used the Instant Transmission to arrive on Earth and kill Future Freeza and Future King Cold (something Future Trunks Briefs' arrival in the main timeline alterd). Sometime after this, Future Yamucha and Future Bulma Brief broke up. She later had a baby with Future Vegeta. Two years later, in 766 Age, Future Goku died from a lethal Heart Virus and was unable to be wished back due to the death being of natural causes.
Battle against the Artificial Humans
On the May, 10th 767 Age, two killer Artificial Humans appeared. Coming to the defence of Earth's inhabitants, Future Yamucha and the other Z Warriors engaged the Artificial Humans in battle. Future Yamucha was killed by Future No. 17 with a powerful kick to the neck. The only survivor of the battle was Future Son Gohan, who then dedicated his life to avenging his fallen friends.
- Future Yamucha's death differs between The History of Trunks and Future Trunks' flashback. In The History of Trunks, he is shown in the prologue being killed by a powerful kick to the neck by Future No. 17. In the flashback, however, he is shown having a hole blasted through his chest by Future No. 17, therefore his true death is debatable.
- Future Yamucha is considerably weaker then his main timeline counterpart as he did not train vigorously for the arrival of the Artificial Humans as his present counterpart did. Obviously, he was not aware of their impending arrival.
- Future Yamucha is 34 years old when he dies.