Prop questions

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FormerParatrooper
Posts: 170
Joined: 05 May 2016, 18:46
Location: Central Illinois

Prop questions

Post by FormerParatrooper » 01 Jul 2016, 00:08

Prop questions:

The manual calls for a 8x81/2 prop for my 67 Johnson 9.5. What is on it is a 8 1/4 x 8 1/2 . Is this enough difference that when I replace this prop for what the manual calls for that I will see a noticeable difference in performance?

These are pics of my current prop, it is dinged pretty good. I noticed some deformations on the blades themselves, what is the cause of this? What can I do to reduce it from happening? Or is it a badly made prop?
20160627_113326.jpg
20160627_113238.jpg
1979 MirroCraft F4604
1967 Johnson MQ13 9.5 Hp
1974 Evinrude 25452M 25 Hp

Life member of the LGOPPs

Xtremeboats
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DaleH
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Joined: 12 Dec 2014, 14:32
Location: Eastern Mass

Prop questions

Post by DaleH » 01 Jul 2016, 07:51

I'd use that prop, the 1/4" difference in diameter won't mean anything.

The dings are from someone grounding the OB in shallow water. Don't put a file to it. I smooth out prop dings on aluminum blades using crocus/metal cloth wrapped around a hardwood block.

How to prevent them :?: ? Watch out in shallow water ...
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
#4 Procraft SV14
#5) 16' Starcraft entirely NEW Transom Skins http://forum.tinboats.net/viewtopic.php?f=3&t=37548

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FormerParatrooper
Posts: 170
Joined: 05 May 2016, 18:46
Location: Central Illinois

Prop questions

Post by FormerParatrooper » 05 Jul 2016, 11:10

Thank you Dale. I will be following your advice. I am purchasing a new prop just to have a back up for anything that may happen on the water. I believe better to be safe and have a spare than to need one and not have it. I have a spare for about everything else that could wrong so a prop would be a good investment.
1979 MirroCraft F4604
1967 Johnson MQ13 9.5 Hp
1974 Evinrude 25452M 25 Hp

Life member of the LGOPPs

dootech
Posts: 32
Joined: 23 Oct 2015, 16:29
Location: Twin cities, Minnesota

Prop questions

Post by dootech » 10 Jul 2016, 21:57

I've used hammer and file to straighten and smooth blades on many a pwc impeller, and those are very sensitive to cavition

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