High Five owners. Prop experts. Merc 4.3

[RSVRMAN]

Got a new/used prop from a prop shop. Shop said I can return it if I?m unhappy. Said he was pretty sure I?d love this prop and got a really good price on it. I currently have a 1995 Sea Ray 185 with a 4.3L Mercruiser. I?m fairly certain my outdrive has a 1.82 ratio. Alpha 1 Gen 2.

I previously had a SS 3 blade 17? pitch and was unsure of the diameter. Boat was hitting 4800 at ? throttle without trimming up. The Tach (not GPS) was reading 40 MPH. The blade felt rough on acceleration as well so it?s hard to use this as a guide to what I needed. Felt like trying to pick tires out for a car and test driving on them flat.
I will be looking at 75% watersports and just cruising. Top speed isn?t a big deal, but would be nice to still not be going over the 4800 rpm at WOT.

There may be up to 4 adults @ 180 lbs each, but typically just 2.
Prop shop sold me a SS High Five. It says 23P on it and does have the vent holes. There are plugs in the holes right now to make them smaller.

I?ve been reading a lot about this prop since purchase and most people seem to like it. I know I will have to go out and just test it, but curious if anyone else is running a 23P with an 18? 4.3L. Boat is that 175hp and not the 190 hp.

Thanks for your time.

 

[steelespike]

Re: High Five owners. Prop experts. Merc 4.3

As I understand it the vented props aren't particularly effective on a I/O. No matter the high 5 will have amazing grip.
I don't think you will have any over rev problems might struggle to reach rpm. Your speed should be pretty awesome, water sports may be a little sluggish with the 23" pitch.I do wonder about your rpm. A 6" increase in pitch could knock 1200 rpm off your wot.
But your true wot now is probably over 5000. I guess we will see.
Looking forward to your results.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

As I understand it the vented props aren't particularly effective on a I/O. No matter the high 5 will have amazing grip.
I don't think you will have any over rev problems might struggle to reach rpm. Your speed should be pretty awesome, water sports may be a little sluggish with the 23" pitch.I do wonder about your rpm. A 6" increase in pitch could knock 1200 rpm off your wot.
But your true wot now is probably over 5000. I guess we will see.
Looking forward to your results.

Thanks for your reply! Thats what I was thinking. I've read that others with the High-Five are running 21" Pitch with my size of boat and the 4.3L. Id rather underprop than over prop just incase I ever were to add more weight to the boat. At WOT is it ok to be in the 4400-4600 or should I really focus on the 4600-4800.

 

[steelespike]

Re: High Five owners. Prop experts. Merc 4.3

I believe your rpm range is 4400 to 4800.with a 1.81 gear ratio.I do think with 75% water sports you should shoot for 4600-4800.
The closer to 4800 the better for hole shot and less finicky slow cruising speed.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

I believe your rpm range is 4400 to 4800.with a 1.81 gear ratio.I do think with 75% water sports you should shoot for 4600-4800.
The closer to 4800 the better for hole shot and less finicky slow cruising speed.

Sounds good. Couple of "newbie" questions. When I hit the full throttle should I be at the 4600-4800 range right away or is that the rpm the boat would be at when its fully trimmed and going full speed. I guess I'm unclear when or what the WOT should be calculated at.

Additionally I plan on pulling two tubes and wakeboarding. Will that drop the WOT on a launch?

Hoping to get on the lake tomorrow when its not raining to test this prop. I won't be able to pull someone behind it for awhile until it gets warm and I don't have a lot of experience pulling people with a boat.

Thanks again.

 

[aerobat]

Re: High Five owners. Prop experts. Merc 4.3

As I understand it the vented props aren't particularly effective on a I/O.

as long we are talking I/O with through hub exhaust - why ?

 

[steelespike]

Re: High Five owners. Prop experts. Merc 4.3

As I understand it the Exhaust volume isn't the same as a 2 strokeWith a 2 stroke you get exhaust on every stroke.
A 4 stroke is is every 4th stroke.

 

[aerobat]

Re: High Five owners. Prop experts. Merc 4.3

LOL ...

the pulses of the exhaust gases result in a common exhaust hub to a total volume , regardless of the strokes . the total volume of a 100 hp 2 stroke and a 100 hp 4 stroke is rougly the same even when the pulses on the manifold are different. do you calculate the prop with help of the moon gravity ?

i never heared any manufacturer does not recommend a ventilated prop on a 4 stroke .

just joking and laughing, hoped to hear a more fundamental answer.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

Could either of you answer my WOT question? When from a stop should I be at WOT 4600-4800 or is that more of the range you want to be at Max when fully trimmed? When your pulling does that affect the RPM from a stop?

 

[Tail_Gunner]

Re: High Five owners. Prop experts. Merc 4.3

Works like this..you attain wot with your leg or drive fully trimmed out for maxium speed.. So on start your fully trimmed in to keep the bow down and maxium grip. once on plane you trim out the leg so the boat setas on its keel for max lift and grip..Sorry if thats not clear im working on a electrical issue and my brian is somewhat in a state of schock.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

Works like this..you attain wot with your leg or drive fully trimmed out for maxium speed.. So on start your fully trimmed in to keep the bow down and maxium grip. once on plane you trim out the leg so the boat setas on its keel for max lift and grip..Sorry if thats not clear im working on a electrical issue and my brian is somewhat in a state of schock.

Thanks you cleared it up a bit. When the boat is going stop to hole-shot is there a RPM I should be looking for or does it not matter? For example on a hole shot boat is holding 3k and then builds to 4k and so on or should sit at 4k? Or is this more of a drive by the seat of your pants thing and your boat is pulling strong.

 

[jestor68]

Re: High Five owners. Prop experts. Merc 4.3

A "vented" prop simply introduces exhaust gases into the propeller stream(causing ventilation on purpose) to allow the prop to "slip" on initial acceleration. This allows the engine to rev higher than it would otherwise, supposedly producing more power to get up out of the hole quicker, while still being able to run monster props(26,28 pitch).

Bear in mind that these props were designed for tail heavy bass boats to help get them on plane a little faster.

The amount of engine rpm generated upon initial hit of the throttle from a stop is dependent on the gear ratio,size of the prop, and hp available. Generally speaking, lower gearing and lots of blade area generate the most static thrust. Static thrust is what initially pushes the boat forward(and what pulls the skier up). Venting the prop can actually reduce static thrust, and is therefore questionable for pulling duties. That's why the vent holes are plugged on that prop.

I suspect that a 23 pitch may be over kill, with a 19 being more appropriate. But you'll have to try it and see. If it doesn't get up to the recommended rpm range, give it back.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

A "vented" prop simply introduces exhaust gases into the propeller stream(causing ventilation on purpose) to allow the prop to "slip" on initial acceleration. This allows the engine to rev higher than it would otherwise, supposedly producing more power to get up out of the hole quicker, while still being able to run monster props(26,28 pitch).

Bear in mind that these props were designed for tail heavy bass boats to help get them on plane a little faster.

The amount of engine rpm generated upon initial hit of the throttle from a stop is dependent on the gear ratio,size of the prop, and hp available. Generally speaking, lower gearing and lots of blade area generate the most static thrust. Static thrust is what initially pushes the boat forward(and what pulls the skier up). Venting the prop can actually reduce static thrust, and is therefore questionable for pulling duties. That's why the vent holes are plugged on that prop.

I suspect that a 23 pitch may be over kill, with a 19 being more appropriate. But you'll have to try it and see. If it doesn't get up to the recommended rpm range, give it back. You'll be better off with an aluminum 15.5 X 17 3 blade and still be able to pull like crazy.

Thanks for the advice! I will still give it a try (hopefully today) and post back my results. Many of the posts I've read on them have owners trying them with no followup. I previously had a 17" pitched SS blade and was hitting above WOT very easilly. I would like a smoother throttle as well. If it is over propped I will go from there what my WOT is and see what to do. I may also try a REV 4.

Im super excited to try it as I also already have trim tabs. Hoping for a very fast plane time. My other half really struggles to get up on skis and this would greatly help her. If not hopefully I can get her let me purchase a tower for the following year.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

Well I got to test the High Five 23P with the small vent hole plugs and I've decided to weld it to my shaft. After taking multiple laps twists and turns around the lake you would have to pry it from my cold dead hands. I did lots of dead stop hole shots as well. My boat was level before I engaged and stayed there all the way until I reached Max RPM. I do have trim tabs, but man did I plane fast. It was 1-2 seconds that I was up with a nice wake behind me.:lock1::lock1:

Additionally I was able to according to my tach (which isn't gps working on getting one) stay on plane at 17mph.lane:lane: I also got to play with speed a bit and test how sharp of wake I could get. I was worried with trim tabs that it would not produce a nice wake, yet I was wrong. I also was able to get up to 54MPH fully trimmed. RPM gauge was dead on 4800 RPM.

I want to add when I hit the throttle from stop boat hit 4000 RPM instantly and climbed from there. I'm unsure if the vent holes have anything to do with this, but when I ran from the 17 pitch it seemed to start at 3500 RPM and climb from there.

Backing up is more difficult. Seems to drift easily. Lake was calm and almost glass like.

The engine seemed to run much smoother on acceleration and out of the hole. The turning actually frightened me. I don't have a lot of experience with spin out, but my last prop (3 blade 17 pitch ) seemed to drift as I cornered. Sorry I don't know what its called, but I knew from the seat of my pants it didn't feel right. This one just stuck. I was able to carve hard into the water. Almost felt like I was back on my motorcycle on a track day!

I had 3 people including myself in the boat with a full tank of gas and gear for testing. The combined weight of us would be approximately 550lbs. Gear including anchor, life vests, full cooler of ice and tubes could add up to an additional 200lbs to the 550. Trying to be as specific as I can for future prop searches. :help:

Sea Ray according to nada is 2600LBS. It is a 1995 185 5 series. I have the 4.3 2BBL Carb. eace:

 

[TyroneShoelaces]

Re: High Five owners. Prop experts. Merc 4.3

Interesting OP, I've got a similar sized boat and Merc 4.3l and have been eyeballing the high five. Currently running a 21" aluminum and want better grunt now that the kids are getting older and doing more watersports (and I think I found some oysters). I was considering the 19", or possibly the 21. I would have thought the 23" would have spun way too fast and lost pull, but your review has me definately thinking the 21" now. I have to do some tests this weekend on my AL prop, but gonna grab a Craigslist SS 3 blade 19" to try for a bit as funds are not plentiful at the moment and the high 5's are pretty spendy. Thanks for the great review.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

Interesting OP, I've got a similar sized boat and Merc 4.3l and have been eyeballing the high five. Currently running a 21" aluminum and want better grunt now that the kids are getting older and doing more watersports (and I think I found some oysters). I was considering the 19", or possibly the 21. I would have thought the 23" would have spun way too fast and lost pull, but your review has me definately thinking the 21" now. I have to do some tests this weekend on my AL prop, but gonna grab a Craigslist SS 3 blade 19" to try for a bit as funds are not plentiful at the moment and the high 5's are pretty spendy. Thanks for the great review.

Thank you and good luck on the prop search. Other people may be better at doing prop pitch than me based off your old prop. My boat is shorter but your boat is lighter with the aluminum hull. The 23" would be harder to turn, but has the vent holes. Id probably go with the 21" pitch high five if not sure. Additionally Id look for a qst 5 blade due to it being basically the same thing.Ive seen them on ebay for 250 or check your local craigslist as well. I actually pulles the prop off this weekend as my neighbor wants to try on his fishing 2 stroke boat. Hope to write up a review for that as well.

 

[jjschwi]

Re: High Five owners. Prop experts. Merc 4.3

i have a 2003 4.3 liter sea ray 182 srx, and I run a 19 pitch on my boat, the difference from the aluminum stock prop is nuts!! this prop just grabs in the corners so hard. pulling wakeboarders is a snap. I was dragged pretty far on the stock prop, and jumped me out of the hole on the 19 prop.

I will say though that if I wide open throttle my boat and trim it out for top speed, I do hit the rev limiter, I never really top out my boat like that, so it really isnt a problem, i just have to tap the trim down a bit to lower the rpms. Im either pulling wakeboarders or tubers, or cruising with a bottle of wine, so the top speed doesnt bother me. Its a great prop and I love it! I picked mine up for sale around $500 i think. well worth the performance!

 

[jjschwi]

Re: High Five owners. Prop experts. Merc 4.3

I take that back everything I said about my prop is try except mine was a 21 pitch not the 19... Oops

 

[jestor68]

Re: High Five owners. Prop experts. Merc 4.3

I don't mean to rain on your parade; but your posted results with a 23 pitch prop are way over what the Mercury prop selector indicates what should happen.

There is no indication that your set up can achieve 4800 rpm with a 23 pitch prop(of any kind).

I believe your tach is off, and your speedometer is very optimistic; as the selector indicates that you should be doing about 4600 rpm @ 44-45 mph with a 21, and 4800 rpm with a 19.

In my many years dealing with Mercury props, I have not seen a case where a High Five ran the same speed as the same pitch 3 blade.

The High Five is generally recommended at the same pitch because of it's smaller diameter. That lets it spin up faster, achieving better acceleration, but less top speed.

There is no doubt that your 17 was under propped, since a 21 is what is called for to run about 4600 rpm. Putting a 23 on there should have dropped you to less than the bottom of the rpm range; not the top.

 

[RSVRMAN]

Re: High Five owners. Prop experts. Merc 4.3

I run a fairly light load in my boat. I also have replaced many of the gauges right after I purchased the boat. The tach and speedo were both replaced. They were replaced with new/stock faria gauges. While I'm aware the speedo is not something to be judged by, (I said that I want to get a gps) the tach is accurate. I have enough experience with engines to tell if an engine is lugging by its sound and feel. Sure I cant tell by 200 or even 400 rpm, but from riding on a friends boat with a 4.3L, his wot engine pitch (sound) is identical at 4800. (He is running a rev 4) Additionally the previous poster said was hitting red with a 21p. He has a more powerful engine, but same size boat.

I got this prop recommended from a very reputable prop shop, which is all they do. (Many years of experience) The 3 blade prop I had was wrong for my boat. Im not 100% sure of the cup or diameter but it was wrong. The prop vibrated had a so so hole shot snd hit the rev limiter at 3/4 throttle. That prop should not be used as a comparison at all because it was too off to go by.

All I'm trying to convey is that this prop works great for me and would highly recommend. I have an amazing wake at low speeds with no wash. Fully trimmed I hit 4800 rpm. I may not be able to hit the fastest MPH possible in my boat, but I could care less if I lost 2MPH off the top for all of the benifits of this prop. The boat sticks in power turns and has no bow lift. I stay level with the trim tabs and on plane in seconds with an insane hole shot.

When I worked as a mechanic I was more often going off feel, smell and touch than a handheld machine or a book. This is especially easy with a carbureted engine. Im doing the same with the boat. From the feel in the seat of my pants and smile on my face it works great.