The series will be the final one before West Indies head into the May 30 to July 14 World Cup in England, where they open their campaign against Pakistan on May 31.
However, Ambris and Roston Chase stabilised the innings with a 128-run stand before Chase was clean bowled by Josh Little for 46.
Earlier, Andrew Balbirnie scored a brilliant hundred of his own in an Ireland total of 327 for five. However, Jason Holder (36 off 24) and Jonathan Carter (43* off 27) survived a few jitters to take the side close to the finishing line.
Left-arm pacer Sheldon Cottrell struck in the fifth over with the scalp of McCollum, but Balbirnine held the innings together with a knock that included 11 fours and fours sixes from 124 balls. The batsman recorded his career-best score of 170 runs in the opening match against Ireland and along with fellow opener John Campbell, he registered the highest ever ODI opening partnership of 365 runs. He made sure to make the West Indies pay, when occasionally showing us some vintage Paul Stirling cuts and drives square of the wicket. William Porterfield and Kevin O'Brien are the trusted ones from Ireland. Three of his four sixes came after he had surpassed the three-figure score. He contributed a more than useful 25 not out from 13 balls, including a big six over mid-wicket from the final ball of the innings.
Ireland would have been looking for quick wickets to start the run chase, but the West Indies started with good intent.
The cricket teams of Ireland and the West Indies will meet at the Village in Malahide for the fourth ODI of the Ireland Tri-Nation Series on Saturday. Ambris capitalised fully, and his aggression allowed Hope to tick along without playing extravagant shots.
The in-form Balbirnie put on a 146-run partnership for the second wicket with opener Paul Stirling (77). However, West Indies' firepower in batting meant they had enough in the tank to chase the target down on a flat pitch, even if the outfield was rendered sluggish due to rain on the previous day.
West Indies captan Jaosn Holder.
West Indies, who tops the points table after winning two out of three matches, will face Bangladesh on May 13.
On this day past year, Ireland were preparing to host their first day of Test match cricket, only for rain to delay the historic occasion by 24 hours.
"I'm very positive that we can bounce back against Ireland, and when we play Bangladesh the second time around, we'll put up a much better performance", Holder said.