JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://raw.github.com/douglascrockford/JSON-js/master/json_parse.js"></script>

JavaScript

var data = '{\"Id\":\"1\",\"Sounding\":\"1.075\",\"Ullage\":\"0\",\"Full\":\"100\",\"CapacityM\":\"3.918\",\"CapacityMT\":\"3.918\",\"LCG\":\"3.779\",\"TCG\":\"0\",\"VCG\":\"2.39\",\"FSM\":\"4.492\"}';

function json_parse(data, function(key, value) {
    var floatVal = parseFloat(value);
    return !isNaN(floatVal) && isFinite(value) ? floatVal : value;
});

alert(json_parse(data).Id);