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Old 18 November 2012, 14:57   #1
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Prop advice please (picture)

Hi all, please excuse me if this is a nieve question but would this prop be suitable for a 8 hp outboard pushing a 2.8 mtr sib with inflatable keel 2up total weight 220 kgs , and getting "on the plane".

The reason I ask is that this is my set up and to say the performance was woefull would be an understatment . The engine revs would not raise above 2-2500 rpm whilst in gear (revs to 5500 out of gear) and we had a huge wash from the prop plenty of torque but no speed .

The sib was set up right pressure etc, the engine is in top nick for its age spot on compression, spark plug, timing, 20/1 fuel ratio, if its not the prop am i asking too much from an 8 hp?

Any advice would be greatly appreciated, be gentle .[ATTACH][ATTACH]Click image for larger version

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Old 19 November 2012, 12:39   #2
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Doesn't your motor have a thru-hub exhaust? Looks like it based on the bullet.

That prop looks to be made for a V drive or similar with a remote exhaust system. Won't work on a motor with thru-hub exhaust.

jky
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Old 19 November 2012, 14:53   #3
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Hi jky, thankyou for your response, as you can probably tell I am new to all this terminoligy but the exhaust exits through the triangular section you can see pointing down infront of the prop.

I am tempted to go for a Mercury 9.8 on ebay that is stuck in forward gear but turns over so gears not jammed, the seller is not sure of the age though, i will probably be back on here asking for more help in the near future regarding this engine .

I have been told that even with a new 8 hp it would struggle to get on the plane with gear and 2 up 220 kgs , which to be honest surprised me, I thought that the prop looked "abit agricultural" and that I had convinced myself that it was the problem hence the thread
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Old 19 November 2012, 15:46   #4
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That's an oldie non exhaust through hub engine version, no new props available, will need to keep on using as it is or sell your engine and buy a modern through hub exhaust engine in which you have a wide wariety of props to choose from....

A 2.8 meter sib with a small 8 HP has a great hull drag to overcome specially if not delivering full wot rpm. If possible get a modern Tohatsu, Mercury 9.8 much better than a 8...

Happy Boating
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Old 19 November 2012, 16:00   #5
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Originally Posted by Locozodiac View Post
That's an oldie non exhaust through hub prop engine version, no new props available, will need to keep on using as it is or sell your engine and buy a modern through hub exhaust engine in which you have a wide wariety of props to choose from....

Happy Boating
Ooops have just sealed the deal on the Mercury 9.8 hp on ebay I pick it up tomorrow I guess that I will have the same issue with that one should I require a new prop .

Thanks for your reply

Anyone want to buy a duel fuel Yammie 8 hp sweet running engine air cooled Kerosene 72 uk pence per ltr, 1 ltr per hour at 4000 rpm 26 kgs
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Old 19 November 2012, 16:05   #6
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Don't buy non through hub exhaust engines no matter mint conditions, no new props available, don't jump into an empty pool, that injures!! If that's a modern version, will be much better than previous 8 HP.

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Old 19 November 2012, 16:25   #7
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Originally Posted by Locozodiac View Post
Don't buy non through hub exhaust engines no matter mint conditions, no new props available, don't jump into an empty pool, that injures!! If that's a modern version, will be much better than previous 8 HP.

Happy Boating
Looks like this hobby is going to be a very steep learning curve for me, lets hope I don't run out of money before I get it right

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Old 19 November 2012, 16:55   #8
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Quote:
Originally Posted by bartiny View Post
Hi jky, thankyou for your response, as you can probably tell I am new to all this terminoligy but the exhaust exits through the triangular section you can see pointing down infront of the prop.

I am tempted to go for a Mercury 9.8 on ebay that is stuck in forward gear but turns over so gears not jammed, the seller is not sure of the age though, i will probably be back on here asking for more help in the near future regarding this engine .

I have been told that even with a new 8 hp it would struggle to get on the plane with gear and 2 up 220 kgs , which to be honest surprised me, I thought that the prop looked "abit agricultural" and that I had convinced myself that it was the problem hence the thread
I would just like to know if i could put a 19" prop on my 2.5 mariner any advice please
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Old 19 November 2012, 17:01   #9
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Nobody is born with boating skills, it's a learning curve. It's a pity to see new boaters getting so excited purchasing their new toys to find out days latter that their purchase was not the best one. Good time for sellers to get rid of old boats & engines scamming buyers in benefit of themselves. Something like get rid of today fast or keep forever...

If it's a rebadged Tohatsu 2.5 non through hub prop, correct ranges are : 7.4 diam x 4.3/5.7/7.0 pitch available in plastic or metal.

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Old 19 November 2012, 17:09   #10
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I would just like to know if i could put a 19" prop on my 2.5 mariner any advice please
Hi, I do not have much experience but i would say yes as long as you have access to an angle grinder

Good luck
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