1991 johnson v8 300 gt counter rotating prop selection

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varvatos

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Hi everyone,<br />I am new to this forum and thank everyone in advance for all the help they will provide me with.<br /><br />I just purchased a Johnson V8 300hp gt counter rotating and am now trying to find out how to determin the right propeller for this monster. I have a 30ft boat, which i would like to equip with that motor. it has a deep V hull and wheighs around 1200 kilogram (1.2 tons). i don't know much more about it. Can someone help me determine what prop I will need to put on the motor??<br />Thanks a bunch
 
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walleyehed

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Re: 1991 johnson v8 300 gt counter rotating prop selection

For a situation like this, we need to borrow a prop if we can find a dealer or a friend that would let you try it...There is no 1 set prop for any engine, on any one boat....we gotta take a stab and start testing.<br />A 15X17 OMC P/N 391200 "might" be a starting point for a reference.
 
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Dhadley

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Feb 4, 2001
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Re: 1991 johnson v8 300 gt counter rotating prop selection

Just so we're all on the same page (so to speak) here's what I posted in answer to your other post --<br /><br />The rev limiter on that motor should be at 6700. Don't be afraid to turn it up but do be afraid to lug it. 6000 should be about the lowest target rpm with an average load.<br /><br />A GT (or XP) should be a 20" motor. Keep in mind the 20" V8's are actually 23". I take it from your post that it's a single on a 30' boat. Depending on how it's set up (bracket mount, transom mount, jack mount etc) it's probably set up for a 25" motor. The 20" V8 is probably a good match given the actual mid section length.
 
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walleyehed

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Re: 1991 johnson v8 300 gt counter rotating prop selection

The P/N, 391200, is right-hand rotation...you ned the left-hand and I don't have that P/N at this location.
 
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varvatos

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Re: 1991 johnson v8 300 gt counter rotating prop selection

thanks walleyehed, and dhadley.<br />dhadley: it was taken of a 30 foot boat with two engines. but the right hand rotation one is broken so i just bought the CR one. <br />it appears to be very difficult to find a prop for this engine.<br />does aluminum work or do I need stainless steel? can the engine break if i don't have the right prop? should i buy three different propellers to test with and if yes, which once?<br />thanks for all your help again.<br />Stefan
 
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