diff --git a/moment-timezone.js b/moment-timezone.js
index 79a0c035..f4b4ae15 100644
--- a/moment-timezone.js
+++ b/moment-timezone.js
@@ -547,7 +547,9 @@
 				offset = offset / 60;
 			}
 			if (mom.utcOffset !== undefined) {
+				var z = mom._z;
 				mom.utcOffset(-offset, keepTime);
+				mom._z = z;
 			} else {
 				mom.zone(offset, keepTime);
 			}
@@ -584,10 +586,19 @@
 		};
 	}
 
-	fn.zoneName = abbrWrap(fn.zoneName);
-	fn.zoneAbbr = abbrWrap(fn.zoneAbbr);
-	fn.utc      = resetZoneWrap(fn.utc);
+	function resetZoneWrap2 (old) {
+		return function () {
+			if (arguments.length > 0) this._z = null;
+			return old.apply(this, arguments);
+		};
+	}
 
+	fn.zoneName  = abbrWrap(fn.zoneName);
+	fn.zoneAbbr  = abbrWrap(fn.zoneAbbr);
+	fn.utc       = resetZoneWrap(fn.utc);
+	fn.local     = resetZoneWrap(fn.local);
+	fn.utcOffset = resetZoneWrap2(fn.utcOffset);
+	
 	moment.tz.setDefault = function(name) {
 		if (major < 2 || (major === 2 && minor < 9)) {
 			logError('Moment Timezone setDefault() requires Moment.js >= 2.9.0. You are using Moment.js ' + moment.version + '.');
diff --git a/tests/moment-timezone/utc.js b/tests/moment-timezone/utc.js
index ce78026a..6fa0c184 100644
--- a/tests/moment-timezone/utc.js
+++ b/tests/moment-timezone/utc.js
@@ -7,10 +7,12 @@ exports.utc = {
 	utc : function (test) {
 		moment.tz.add([
 			"TestUTC/Pacific|PST|80|0|",
+			"TestUTC/Mountain|MST|70|0|",
+			"TestUTC/Central|CST|60|0|",
 			"TestUTC/Eastern|EST|50|0|"
 		]);
 
-		var m = moment("2014-07-10 12:00:00+00:00"),
+		var m = moment("2014-07-10T12:00:00+00:00"),
 			localFormat = m.format(),
 			localOffset = helpers.getUTCOffset(m);
 
@@ -18,29 +20,52 @@ exports.utc = {
 
 		test.equal(helpers.getUTCOffset(m), -480, "Should change the offset when using moment.fn.tz");
 		test.equal(m.format(), "2014-07-10T04:00:00-08:00", "Should change the offset when using moment.fn.tz");
+		test.equal(m.tz(), "TestUTC/Pacific", "Should set the time zone name when using moment.fn.tz");
 
 		m.utc();
 		moment.updateOffset(m);
 
 		test.equal(helpers.getUTCOffset(m), 0, "Should set the offset to +00:00 when using moment.fn.utc");
 		test.equal(m.format(), "2014-07-10T12:00:00Z", "Should change the offset when using moment.fn.utc");
+		test.equal(m.tz(), undefined, "Should clear the time zone name when using moment.fn.utc");
 
-		m.tz("TestUTC/Eastern");
+		m.tz("TestUTC/Mountain");
 
-		test.equal(helpers.getUTCOffset(m), -300, "Should change the offset when using moment.fn.tz");
-		test.equal(m.format(), "2014-07-10T07:00:00-05:00", "Should change the offset when using moment.fn.tz");
+		test.equal(helpers.getUTCOffset(m), -420, "Should change the offset when using moment.fn.tz");
+		test.equal(m.format(), "2014-07-10T05:00:00-07:00", "Should change the offset when using moment.fn.tz");
+		test.equal(m.tz(), "TestUTC/Mountain", "Should set the time zone name when using moment.fn.tz");
 
 		m.utc();
 		moment.updateOffset(m);
 
 		test.equal(helpers.getUTCOffset(m), 0, "Should set the offset to +00:00 when using moment.fn.utc");
 		test.equal(m.format(), "2014-07-10T12:00:00Z", "Should change the offset when using moment.fn.utc");
+		test.equal(m.tz(), undefined, "Should clear the time zone name when using moment.fn.utc");
+
+		m.tz("TestUTC/Central");
+
+		test.equal(helpers.getUTCOffset(m), -360, "Should change the offset when using moment.fn.tz");
+		test.equal(m.format(), "2014-07-10T06:00:00-06:00", "Should change the offset when using moment.fn.tz");
+		test.equal(m.tz(), "TestUTC/Central", "Should set the time zone name when using moment.fn.tz");
 
 		m.local();
 		moment.updateOffset(m);
 
 		test.equal(helpers.getUTCOffset(m), localOffset, "Should reset the offset to local time when using moment.fn.local");
 		test.equal(m.format(), localFormat, "Should reset the offset to local time when using moment.fn.local");
+		test.equal(m.tz(), undefined, "Should clear the time zone name when using moment.fn.local");
+
+		m.tz("TestUTC/Eastern");
+
+		test.equal(helpers.getUTCOffset(m), -300, "Should change the offset when using moment.fn.tz");
+		test.equal(m.format(), "2014-07-10T07:00:00-05:00", "Should change the offset when using moment.fn.tz");
+		test.equal(m.tz(), "TestUTC/Eastern", "Should set the time zone name when using moment.fn.tz");
+
+		m.utcOffset('+02:00')
+
+		test.equal(helpers.getUTCOffset(m), 120, "Should change the offset when using moment.fn.utcOffset");
+		test.equal(m.format(), "2014-07-10T14:00:00+02:00", "Should change the offset when using moment.fn.utcOffset");
+		test.equal(m.tz(), undefined, "Should clear the time zone name when using moment.fn.utcOffset");
 
 		m = moment('2017-01-01T00:00:00');
 		var utcWallTimeFormat = m.clone().utcOffset('-05:00', true).format();