diff --git a/opm/io/eclipse/ESmry.hpp b/opm/io/eclipse/ESmry.hpp
index c45a68209..7c7d03366 100644
--- a/opm/io/eclipse/ESmry.hpp
+++ b/opm/io/eclipse/ESmry.hpp
@@ -61,7 +61,8 @@ public:
 
     bool make_esmry_file();
 
-    time_point startdate() const { return startdat; }
+    time_point startdate() const { return tp_startdat; }
+    std::vector<int> start_v() const { return start_vect; }
 
     const std::vector<std::string>& keywordList() const;
     std::vector<std::string> keywordList(const std::string& pattern) const;
@@ -110,7 +111,8 @@ private:
     std::vector<SummaryNode> summaryNodes;
     std::unordered_map<std::string, std::string> kwunits;
 
-    time_point startdat;
+    time_point tp_startdat;
+    std::vector<int> start_vect;
 
     mutable double m_io_opening;
     mutable double m_io_loading;
diff --git a/opm/io/eclipse/ExtESmry.hpp b/opm/io/eclipse/ExtESmry.hpp
index c03223c14..b90cc4723 100644
--- a/opm/io/eclipse/ExtESmry.hpp
+++ b/opm/io/eclipse/ExtESmry.hpp
@@ -54,6 +54,7 @@ public:
     void loadData(const std::vector<std::string>& stringVect);
 
     time_point startdate() const { return m_startdat; }
+    std::vector<int> start_v() const { return m_start_vect; }
 
     bool hasKey(const std::string& key) const;
 
@@ -93,6 +94,7 @@ private:
     std::vector<uint64_t> m_rstep_offset;
 
     time_point m_startdat;
+    std::vector<int> m_start_vect;
 
     double m_io_opening;
     double m_io_loading;
diff --git a/src/opm/io/eclipse/ESmry.cpp b/src/opm/io/eclipse/ESmry.cpp
index f3733512d..c957d6ebd 100644
--- a/src/opm/io/eclipse/ESmry.cpp
+++ b/src/opm/io/eclipse/ESmry.cpp
@@ -180,7 +180,8 @@ ESmry::ESmry(const std::string &filename, bool loadBaseRunData) :
         std::vector<std::string> combindKeyList;
         combindKeyList.reserve(dimens[0]);
 
-        this->startdat = make_date(smspecList.back().get<int>("STARTDAT"));
+        start_vect = smspecList.back().get<int>("STARTDAT");
+        this->tp_startdat = make_date(start_vect);
 
         if ( have_lgr ) {
             for (unsigned int i=0; i<keywords.size(); i++) {
@@ -312,8 +313,6 @@ ESmry::ESmry(const std::string &filename, bool loadBaseRunData) :
         std::vector<std::string> combindKeyList;
         combindKeyList.reserve(dimens[0]);
 
-        this->startdat = make_date(smspecList.back().get<int>("STARTDAT"));
-
         if (have_lgr) {
             for (size_t i = 0; i < keywords.size(); i++) {
                 Opm::EclIO::lgr_info lgr { lgrs[i], {numlx[i], numly[i], numlz[i]}};
@@ -375,7 +374,6 @@ ESmry::ESmry(const std::string &filename, bool loadBaseRunData) :
     for (int i = 0; i < nSpecFiles; i++)
         arrayPos.push_back({});
 
-    // tskille: testing
     std::map<std::string, int> keyIndex;
     {
         size_t m = 0;
@@ -445,8 +443,6 @@ ESmry::ESmry(const std::string &filename, bool loadBaseRunData) :
     int step = 0;
     specInd = nSpecFiles - 1;
 
-    //nVect = keywList.size();
-
     int index = 0;
     for (const auto& keyw : keywList) {
         if (!keyw.empty()) {
@@ -1044,10 +1040,13 @@ bool ESmry::make_esmry_file()
         this->loadData();
 
         {
-            Opm::TimeStampUTC ts( std::chrono::system_clock::to_time_t( startdat ));
+            std::vector<int> start_date_vect = start_vect;
 
-            std::vector<int> start_date_vect = {ts.day(), ts.month(), ts.year(), ts.hour(),
-                                                ts.minutes(), ts.seconds(), 0 };
+            int sec = start_date_vect[5] / 1000000;
+            int millisec = (start_date_vect[5] % 1000000) / 1000;
+
+            start_date_vect[5] = sec;
+            start_date_vect.push_back(millisec);
 
             std::vector<std::string> units;
             units.reserve(keyword.size());
@@ -1055,6 +1054,7 @@ bool ESmry::make_esmry_file()
             for (auto key : keyword)
                 units.push_back(kwunits.at(key));
 
+
             Opm::EclIO::EclOutput outFile(smryDataFile, false, std::ios::out);
 
             outFile.write<int>("START", start_date_vect);
@@ -1363,7 +1363,7 @@ std::vector<Opm::time_point> ESmry::dates() const {
     std::vector<Opm::time_point> d;
 
     for (const auto& t : this->get("TIME"))
-        d.push_back( this->startdat + std::chrono::duration_cast<std::chrono::seconds>( std::chrono::duration<double, std::chrono::seconds::period>( t * time_unit)));
+        d.push_back( this->tp_startdat + std::chrono::duration_cast<std::chrono::seconds>( std::chrono::duration<double, std::chrono::seconds::period>( t * time_unit)));
 
     return d;
 }
diff --git a/src/opm/io/eclipse/ExtESmry.cpp b/src/opm/io/eclipse/ExtESmry.cpp
index c3b9eeddb..47f4cb5b8 100644
--- a/src/opm/io/eclipse/ExtESmry.cpp
+++ b/src/opm/io/eclipse/ExtESmry.cpp
@@ -51,7 +51,7 @@ Opm::time_point make_date(const std::vector<int>& datetime) {
     auto minute = 0;
     auto second = 0;
 
-    if (datetime.size() == 6) {
+    if (datetime.size() == 7) {
         hour = datetime[3];
         minute = datetime[4];
         auto total_usec = datetime[5];
@@ -293,15 +293,15 @@ bool ExtESmry::open_esmry(const std::filesystem::path& inputFileName, ExtSmryHea
     if ((arrName != "START   ") or (arrType != Opm::EclIO::INTE))
         OPM_THROW(std::invalid_argument, "reading start, invalid esmry file " + inputFileName.string() );
 
-    std::vector<int> start_vect;
+
     try {
-        start_vect = Opm::EclIO::readBinaryInteArray(fileH, arr_size);
+        m_start_vect = Opm::EclIO::readBinaryInteArray(fileH, arr_size);
     } catch (const std::runtime_error& error)
     {
         return false;
     }
 
-    auto startdat = make_date(start_vect);
+    auto startdat = make_date(m_start_vect);
 
     try {
        Opm::EclIO::readBinaryHeader(fileH, arrName, arr_size, arrType, sizeOfElement);