# Four blade prop



## lawrence p (Sep 3, 2015)

ok guy I know I'll get a honest opinion here. So I am looking for a four blade ss prop for my 2013 four stroke 150 hp Mercury now I have researched this and got a few different answers some say go down in size from my three blade it's a 19p so go to a 17p some say stay the same. What's the general opinion. And also should I stick with mercury or some say they love solas props.


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## UFM82 (Apr 6, 2004)

What 3 blade are you running now? What is your WOT? If you are currently running a Merc prop then you probably already have the hub and only need to buy a prop. But it depends on what you are trying to accomplish. More speed? Bow lift? What kind of boat? My own experience took me through 7 props before I found the one that worked for me. Of those, I tried a Revolution 4 and a Trophy and neither accomplished what I wanted. I was looking for speed, the ability to hold the now up at WOT to eliminate porpoising and bite at high trim levels. I run a 19' offshore style center console that weighs 2,000 lbs, just hull weight. 
Now that I've rambled, you normally drop a pitch when going from 3 blades to 4 blades. So, a 17 to replace the 19 would be normal but again, it depends on other factors. That is not always the case. I run a 19 pitch Tempest and WOT is right at 50 @ 5700. My best with a 17 pitch Rev 4 was 47 @ 5650. So, slightly slower and almost the same RPM but the 4 blade would not hold the now up and the boat porpoised badly.


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## Riverduck11 (Jul 11, 2013)

Like the first poster, it depends exactly what you are looking for and what numbers with which prop you have now. 

I switched to a four blade this year and could not be happier. I wanted it it for throttle response and a lower planing speed on Lake Erie. I ended up going from a 19 Tempest to a 19 trophy plus. Keep us posted.


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## lawrence p (Sep 3, 2015)

I am running a 19p I guess Mercury it is just the aluminum one that came with the boat. I am happy with it for small lakes but I want the 4 blade for Lake Erie so I have quicker response the loss of top speed dosent really matter to me. I kinda take it easy going out and coming in I don't want to loosen rivets on my boat so I take it easy and I want all my fillings in my teeth lol. By the way it on a 2013 Lund crossover 1875 it's 19' long.


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## Riverduck11 (Jul 11, 2013)

Going from aluminum to stainless you may not loose any speed and you will gain in many areas. You will be able to turn tighter, have better throttle response, troll slightly slower. 

I highly suggest it, my boat feels like a whole new boat with my trophy plus now. By the way I only lost 1 mph on the top so the top end speed is negligible.


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## Gottagofishn (Nov 18, 2009)

+1 on the stainless. It made all the difference on my 1875. I'm running a three blade Tempest Plus. As mentioned above the stainless gives more bite. On my boat it was like riding in a different boat after adding the stainless. 
Find yourself a good prop shop and give one a spin.....


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## lawrence p (Sep 3, 2015)

Riverduck11 are you running a Mercury 150 I think I am going with the trophy plus but I have read a few guys going with a 19p instead of going down in size


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## Riverduck11 (Jul 11, 2013)

Yes I am running the 150 Fourstroke on a Ranger Reata 1850LS. So my boat is a bit heavier than yours but similar length and beam. I really think a 19 pitch trophy plus would be great on your boat. I would not go down in prop to start with for sure. There are several companies online that let you test props and you only end up paying for the shipping as you return them.

I would start with 4 solid vent plugs in the prop and then just drill them out as you need to go up in RPM's. I was given this tip from a guy at Mercury and it saved lots of time and money always buying new vent plugs.


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## lawrence p (Sep 3, 2015)

Cool thanks a ton


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## Popspastime (Apr 1, 2014)

Go to the Spitfire X7 4 blade same pitch you have now and don't look back.


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## jQuit (Nov 16, 2011)

lawrence p said:


> Riverduck11 are you running a Mercury 150 I think I am going with the trophy plus but I have read a few guys going with a 19p instead of going down in size


The prop shop with know how is the best I've read. In general it is correct that 4 blades give more bite and increased power if the RPM doesn't drop. Dropping pitch also gives more power but less boat speed. The variables are boat weight, hull shape, prop power match, and motor RPM. Too much RPM can damage your engine. This is why people trying the try it and see method buy a lot of props.


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## UFM82 (Apr 6, 2004)

The vent plugs won't help a 4 stroke like they do a 2 stroke. They are there to let some exhaust gas pass out of the hub barrel in front of the blades. This aerates the water, allows the prop to slip a bit and gets the rpm up faster on the 2 stroke. The 4 stroke doesn't rely on that so much.


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## Riverduck11 (Jul 11, 2013)

UFM82 said:


> The vent plugs won't help a 4 stroke like they do a 2 stroke. They are there to let some exhaust gas pass out of the hub barrel in front of the blades. This aerates the water, allows the prop to slip a bit and gets the rpm up faster on the 2 stroke. The 4 stroke doesn't rely on that so much.


I am not familiar with the difference on vent plugs between a 2 and 4 stroke, but I can assure you that you will pick up rpms with open vs closed vent plugs. With 2 open plugs and 2 solid plugs I was just bumping the rev limiter at 5850. Mercury suggests the solid vent plugs would drop about 50 rpms per solid plug. I filled the 2 opens with 2 solid ones and now am always at 5760 to 5780. Have never hit the limiter since switching plugs.


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