Replacement for non thru hub prop

[marsplecko68]

I have a 1977 40hp Mariner that is not exhausted thru the hub, the prop is pretty banged up and I was looking to replace it. This might sound like a stupid question but I wanted to know if I could us a prop that was exhaust thru hub, as when I looked up replacments thats all that show up.

 

[Faztbullet]

Re: Replacement for non thru hub prop

No it will not work, go to a Yamaha dealership or prop shop and have them order one for you. The motor you have is a "import" made by Yamaha for Mariner...

 

[Texasmark]

Re: Replacement for non thru hub prop

When Brunswick first acquired Force engines from West Bend, Chrysler, or whomever, I recall seeing a separate exhaust outlet (like were used prior to Merc developing the thru hub exhaust) and saw that they had thru hub looking props installed also; just like the real Mercs that had real thru hub exhaust.

That told me that the prop was just a "look-alike" and the exhaust was not exiting the prop at all.

Thinking about aquadynamics and all, torpedo shapes and low drag and all that sort of thing, I thought that, if what I thought to be the case were really the case, the Force engines would be very inefficient at the higher speeds where aquadynamics were important. With no exhaust to fill the void behind the prop you would have a suction effect and a lot of drag.

But what do I know.

So, as Fazt said, get the right prop and be happy with it.

My 2c,

Mark

 

[steelespike]

Re: Replacement for non thru hub prop

If your prop isn't too bad a prop shop may be able to repair it.

 

[marsplecko68]

Re: Replacement for non thru hub prop

Thanks to all, everything you say makes perfect sence now.

 

[jay_merrill]

Re: Replacement for non thru hub prop

You may be running into an apparent discrepancy in model year info, on the props that you are looking at.

If you buy an aluminum prop for your motor, no matter what retailer you buy it from, its likely to be made by Michigan Wheel, under the brand name "Michigan Match." I just surfed a few prop retailers and all indicate that the prop type for a 1977 and newer Mariner 40hp (both Bigfoot & non-Bigfoot), is a thru-the-hub style.

The curious part is that, if you go to Michigan Wheel's site and use the prop finder, they indicate that they carry 1978 and newer props for Mariner 40hp models. As you might expect, they are all thru-the-hub types, as well.

I would contact the sales folks right here at iboats and tell them what you need. Be sure to double check the model year of your motor, when you do this. Perhaps they can do the homework for you and get the right prop.



???

 

[marsplecko68]

Re: Replacement for non thru hub prop

You may be running into an apparent discrepancy in model year info, on the props that you are looking at.

If you buy an aluminum prop for your motor, no matter what retailer you buy it from, its likely to be made by Michigan Wheel, under the brand name "Michigan Match." I just surfed a few prop retailers and all indicate that the prop type for a 1977 and newer Mariner 40hp (both Bigfoot & non-Bigfoot), is a thru-the-hub style.

The curious part is that, if you go to Michigan Wheel's site and use the prop finder, they indicate that they carry 1978 and newer props for Mariner 40hp models. As you might expect, they are all thru-the-hub types, as well.

I would contact the sales folks right here at iboats and tell them what you need. Be sure to double check the model year of your motor, when you do this. Perhaps they can do the homework for you and get the right prop.



???

I havn't had to do this much home work since leaving school I have found that if I searched for a 1977 Yamaha in the prop search here & in Rubex & Solas props 3 results come back for Amita 3 pin drive props 11.5 dia 10,11 & 12 pitch. I'm going to ring around tomorrow to get my prop repaired (as per steelespike's advice) but I'd still like to have a spare, just in case.

 

[Texasmark]

Re: Replacement for non thru hub prop

When Brunswick first acquired Force engines from West Bend, Chrysler, or whomever, I recall seeing a separate exhaust outlet (like were used prior to Merc developing the thru hub exhaust) and saw that they had thru hub looking props installed also; just like the real Mercs that had real thru hub exhaust.

That told me that the prop was just a "look-alike" and the exhaust was not exiting the prop at all.

Thinking about aquadynamics and all, torpedo shapes and low drag and all that sort of thing, I thought that, if what I thought to be the case were really the case, the Force engines would be very inefficient at the higher speeds where aquadynamics were important. With no exhaust to fill the void behind the prop you would have a suction effect and a lot of drag.

But what do I know.

So, as Fazt said, get the right prop and be happy with it.

My 2c,

Mark

Anybody out there want to comment on what I said here about Force? I have been curious about it ever since I first saw one configured like this.

Thanks,

Mark

 

[steelespike]

Re: Replacement for non thru hub prop

I don't think Hydrodynamics would affect it much.Especially at the speeds these motors would normally run.But I think the through hub exhaust tends to extract the exhaust better than a snout on a standard application.High performance is a different animal.