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Common Prop Size for Mercruiser 4.3lx

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Common Prop Size for Mercruiser 4.3lx

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Old 04-29-2013 | 09:35 PM
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Default Common Prop Size for Mercruiser 4.3lx

Hi Everyone, I was wondering what a common prob size is for the 4.3lx (4 barrel carb) mercruiser. Right now I could over rev the engine and go over 5k (I dont know how far over as I didnt want to push it). I know recommended rpm ranges is 4600 to 4800. My prop now is 14 x 23. I was going to go with a slightly steeper pitch but realized thats the biggest pitch for 14in, I would prob have to go to a different diameter. The one blade on th prop is bent slightly but would that really cause it to over rev? I will post a picture of it when i get a chance. I mean I could see if there is a huge chunk of metal off the prop but thats not the case. MY boat is a 19ft renkin bow rider and I believe it is 2500 lbs. Thanks for the help!
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Old 04-29-2013 | 11:45 PM
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Originally Posted by jbizub5192
Hi Everyone, I was wondering what a common prob size is for the 4.3lx (4 barrel carb) mercruiser. Right now I could over rev the engine and go over 5k (I dont know how far over as I didnt want to push it). I know recommended rpm ranges is 4600 to 4800. My prop now is 14 x 23. I was going to go with a slightly steeper pitch but realized thats the biggest pitch for 14in, I would prob have to go to a different diameter. The one blade on th prop is bent slightly but would that really cause it to over rev? I will post a picture of it when i get a chance. I mean I could see if there is a huge chunk of metal off the prop but thats not the case. MY boat is a 19ft renkin bow rider and I believe it is 2500 lbs. Thanks for the help!
Something is not right. I had a 19' baja and it could only turn a 21p. Maybe check your hub it might be spinning some.
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Old 04-30-2013 | 06:37 AM
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Check the gearing on your drive . A 4.3 shouldn't be spinning 5k + in a 19' anything with a 23" pitch prop .Something is wrong (slipping) or you have a 4 cylinder geared outdrive.
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Old 04-30-2013 | 08:12 AM
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My first boat was a '93 206 Rinker with a 4.3LX. I ran a 19" Mirage Plus.
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Old 04-30-2013 | 09:29 AM
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Thanks everyone, that's what I kind of thought. Something did not seem right. How can I check the gearing of the drive? Will there be numbers on the drive that identify it if it was a 4 cylinder? I know someone could have just re geared it and if that's the case how would I check for that?
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Old 04-30-2013 | 09:45 AM
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I found a picture of my drive and it says 1.84r. I think that is the correct gear ratio. How can I check the actual ratio? Do I need to remove the drive. My Elevation is at 1128ft if that helps

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Old 04-30-2013 | 10:23 AM
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Something doesn't add up.

Unless it's a very shallow and light boat, that motor in most boats usually only takes a 19 or 21 pitch prop.
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Old 04-30-2013 | 10:37 AM
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like everybody else is saying thee is a missing piece to this puzzle. i am running a 23p michigan wheel on my 18' baja with a 5.7 and it wont rev into the 5000's
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Old 04-30-2013 | 01:38 PM
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I defiantly agree with all of you. When I was looking around I noticed no one had a 23 pitch prop on a 4.3 thats why I figured I would post the question here because something seemed odd lol. Do I have to take the drive off to check the gearing? If so do i need to open up the drive or can I do it by just counting the turns.
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Old 04-30-2013 | 03:23 PM
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What prop is it? Are you sure it's 23P? Is this an Alpha drive? When I got my 190 it had a 19P on it that was pretty chewed up and it would only spin that up to 5200. When I put the 21 on it, it was over proped and would spin 4400.

Did you check the hub?
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