prop has a casted blockage in it?

[gokart83]

I bought a 13X19 prop ($30) used just to test a used 85 140HP that is new to me. Quick History- Blown 92 115HP, got used 140HP, Modified and used my 115 foot and TNT. (never want to thread stainless shift rod again, 3 dies trashed uggghhh) Test ran before TNT with newer 115 foot and bad tach. it litterly jumped out of the water, was scared to go too much as it sounded like too much RPM's. Got a new tach and the new old prop just for testing. Question--- There is a ring on the back of this prop where as my 13X17 has a flange, Why? More important question--- There seems to be a purposely moulded aluminum blocking 1/3 of the thru hub exhaust, Why and should I drill/chip it out for testing? Im going to get a new prop as soon as I know what I need. Any prop Suggestions are very welcomed also. The boat is a 1993 duel console 19' KeyWest. Thanks for any help.

 

[boobie]

Re: prop has a casted blockage in it?

If the "blockage" is in the prop shaft carrier it is most likely an anode installed by the factory. Just make sure it's on the bottom side of the carrier.

 

[gokart83]

Re: prop has a casted blockage in it?

its moulded into the outer casting of the prob where the blades attach with about a 1/16" gap before touching the inner casting that holds the rubbeub in place. My biggeset concern is that it is blocking the exahust from getting out or creating too much back pressure on the engine. This might be normal if its from a smaller motor or it could be designed at an angle as to help relieve backpressure? it is def. blocking 1/3 of the exhaust. Hope this helps and thanks!

 

[boobie]

Re: prop has a casted blockage in it?

Could you post a pict of it ?

 

[gokart83]

Re: prop has a casted blockage in it?

sorry guys, got real busy at work. If you look thru the exhaust as if it were mounted on a motor, you would normally see thru the prop, a spline shaft surrounded by rubber then the aluminum casting of the prop. Around that rubber is the aluminun with 3 legs holding the outer diameter that holds the blades. This is all one casting of aluminum to make up the prop. The 3 "legs" casted in makes 3 open exhaust areas. Now the blockage of aluminum that is part of the one piece casting comes off the outer diameter, is about 1/2" wide(from outer to inner) and 1/3 the circumference( between one of the 3 open spaces exhaust usually exits) it is about 1/16" from touching the inner diameter that holds the rubber. Hope this helps. I will take a pic soon. its at my dads house so propably tomorrow if work allows. Thanks all. Ive gotten alot of good info here in waking up this old 140hp!

 

[clanton]

Re: prop has a casted blockage in it?

If an old prop, probley melted exhaust parts stuck to the prop. If a new prop it is factory defect.

 

[boobie]

Re: prop has a casted blockage in it?

Could be some broken up exhaust deflectors from the p/h also.

 

[gokart83]

Re: prop has a casted blockage in it?

here is a pic of it. My dads Neighbor sad it was probably just overcasting and would not hurt anything. I would think blocking 1/3 of the exhaust would rob alot of power.

 

[boobie]

Re: prop has a casted blockage in it?

From what I can see in the pics it looks like a bad casting. IMHO any blockage in the exhaust can rob power.

 

[gokart83]

Re: prop has a casted blockage in it?

yea, thats what I think also. I think im gonna just drill and chip it out. After all, it is only a cheap used prop for testing. Not much too loose