What Are These Fins On My Motor?

[BoatNoobie]

I originally thought they are OEM or something. But then I noticed other people's motors not having them....

I removed them today while I was putting on a new prop. But there's 4 holes on my lower unit now. So I put the bolts/nuts back on to fill the holes.

What are they for? Should I put them back on? If not, what about the holes on my lower unit.

 

[insanity]

Re: What Are These Fins On My Motor?

They are a hydrofoil to help you get on plain faster and add stability. If you dont like them try smart tabs. If they worked fine before and you like them put them back on its all personal preference.

http://www.iboats.com/Boat-Parts-Ac...665657--submit.Search--submit.x.0--submit.y.0

I have the smart tabs on my boat and love them.

 

[BoatNoobie]

Re: What Are These Fins On My Motor?

They are a hydrofoil to help you get on plain faster and add stability. If you dont like them try smart tabs. If they worked fine before and you like them put them back on its all personal preference.

http://www.iboats.com/Boat-Parts-Ac...665657--submit.Search--submit.x.0--submit.y.0

I have the smart tabs on my boat and love them.

Oh I see. Well I changed props today, so it should feel much different than before already.

Originally had a 10x17p prop. Switched it out to a 10 5/8x12P prop. It's for a Merc 60 4-S on a Lowe FM165. It seems to be the prop most users are using here on iboat.

With my old prop, i was slow off the line. Low RPMs, and lower speed.

 

[NYBo]

Re: What Are These Fins On My Motor?

Remove the nuts and bolts and fill in the holes with black sealant. No sense having that extra drag, as little as it is.

 

[Barnacle_Bill]

Re: What Are These Fins On My Motor?

You should see about 100 RPMs increase. Nake sure you don't over rev past the recommended RPMs. That is just as bad as under reving. You can just leave the holes there they won't hurt anything.

 

[BoatNoobie]

Re: What Are These Fins On My Motor?

You should see about 100 RPMs increase. Nake sure you don't over rev past the recommended RPMs. That is just as bad as under reving. You can just leave the holes there they won't hurt anything.

I hope you meant 1000 RPMs, because before, I was only getting 4500 RPM max.

I'm hoping to hit high 5000s now.

 

[Capt'n Chris]

Re: What Are These Fins On My Motor?

Y

I originally thought they are OEM or something. But then I noticed other people's motors not having them....

I removed them today while I was putting on a new prop. But there's 4 holes on my lower unit now. So I put the bolts/nuts back on to fill the holes.

What are they for? Should I put them back on? If not, what about the holes on my lower unit.

Those fins are definitely the work of a "NOOB".

 

[lncoop]

Re: What Are These Fins On My Motor?

I hope you meant 1000 RPMs, because before, I was only getting 4500 RPM max.

I'm hoping to hit high 5000s now.

I would think 17 to 12 should get you around 1000 more. Rule of thumb is 200 for every 1" drop in pitch.