<SEC-DOCUMENT>0001249991-12-000001.txt : 20120531
<SEC-HEADER>0001249991-12-000001.hdr.sgml : 20120531
<ACCEPTANCE-DATETIME>20120531095235
ACCESSION NUMBER:		0001249991-12-000001
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110701
FILED AS OF DATE:		20120531
DATE AS OF CHANGE:		20120531

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FIELDS RANDOLPH H
		CENTRAL INDEX KEY:			0001249991

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11703
		FILM NUMBER:		12879446

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GENCOR INDUSTRIES INC
		CENTRAL INDEX KEY:			0000064472
		STANDARD INDUSTRIAL CLASSIFICATION:	CONSTRUCTION MACHINERY & EQUIP [3531]
		IRS NUMBER:				590933147
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		5201 N ORANGE BLOSSOM TRAIL
		CITY:			ORLANDO
		STATE:			FL
		ZIP:			32810
		BUSINESS PHONE:		4072906000

	MAIL ADDRESS:	
		STREET 1:		5201 N ORANGE BLOSSOM
		CITY:			ORLANDO
		STATE:			FL
		ZIP:			32810

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MECHTRON INTERNATIONAL CORP
		DATE OF NAME CHANGE:	19880128

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MECHTRON GENCO CORP
		DATE OF NAME CHANGE:	19720411

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MECHTRON CORP
		DATE OF NAME CHANGE:	19690909
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0305</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2011-07-01</periodOfReport>

    <dateOfOriginalSubmission>2011-07-06</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000064472</issuerCik>
        <issuerName>GENCOR INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>GENC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001249991</rptOwnerCik>
            <rptOwnerName>FIELDS RANDOLPH H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.689</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-10-01</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2021-10-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects amendment of Form 4 filed on July 6, 2011 to update the vesting dates.  Options vest and become exercisable in 25% increments on October 1, 2012, October 1, 2013, October 1, 2014, and October 1, 2015.  All options expire on October 1, 2021.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Randolph H. Fields</signatureName>
        <signatureDate>2012-05-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
