[Shamun]

You can look in customer/main/product.tpl then find this:

          {if $product.weight ne "0.00" || $variants ne ''}
            <tr id="product_weight_box">
                <td class="property-name">{$lng.lbl_weight}</td>
                <td class="property-value">
                <span id="product_weight">{$product.weight|formatprice}</span> {$config.General.weight_symbol}
              </td>
            </tr>
          {/if}

and change it to

{*
          {if $product.weight ne "0.00" || $variants ne ''}
            <tr id="product_weight_box">
                <td class="property-name">{$lng.lbl_weight}</td>
                <td class="property-value">
                <span id="product_weight">{$product.weight|formatprice}</span> {$config.General.weight_symbol}
              </td>
            </tr>
          {/if}
*}