I bought my dream boat recently, a 2006 180BR w/the 4.3LMPI with solid ruby gel coat, checkered flag decals, black helm and only 35 hours.  The boat cruises very vell.  However, that is not why I bought it.  This boat is strictly used for water sports.   Here lies my problem, I can't pull a 185lb skier out of the water with just me in the boat(she pulls 3,000 rpm, points her nose in the air, and never reaches plane....yes the boat is trimmed all the way down).  I currently have a 14.25 x 21P stock prop on the boat.  The MPI comes with a 1.62 Alpha 1 gear ratio(this is different than the 4.3L carb which typically has a 1.81) and from what I'm hearing this is the problem.  With the current prop at WOT I get about 53-55mph trimmed out at 4700-4800 RPM.  I did try a Alpha4 14x20P prop.  It did help drop the bow but the boat still struggled.  With the 14x20P the RPM did rise to approx 4950, which is outside of the recommended range.  I'm looking for someone who has experience with my set-up and found something that they think can help.  I did drop an email to Crownline's customer service for their input.  At this point, I'm not sure what my next step is besides selling the boat and going back to Glastron(the boat I owned before this which had a 3.0L and pulled me better than the Crownline).  My gut tells me a Alpha 14x18P would get me what I need but I think I'll be pulling too many RPMs.  Please, please help.

We have the same exact boat, same year everything,, except we have the carb 190hp- 1:81,,  I run a 21p. Enertia SS 3B with 7mm PVS venting plugs, we never pull anything, and always 2 people max. light load.  Hole shot is very good, mid-range cruising is very good (40mph@3800rpm) WOT half tank 51-52mph@4800 always with sweet trim spot, I run this prop because it likes to run at very high trim without slipping, even in rough water and is very efficient.  Your animal is a different situation completely and I'am sure there are people on this forum who knows better than me, I would think you would need a 4B or 5B with some expermenting with prop venting for hole shot but a high enough pitch to take care of excessive RPM@WOT  all this could be very tricky without knowing, maybe find a dealer who would let you try props without buying. anyway 100+ hours on our boat and problem free, good luck.

---

ALLEY CAT,,'06 180 4.3 ruby red, with racing graphics.
Mt. Vernon, Mo.

A BIG DOG IS A TON !!

Ben,

 I don't know a whole lot about prop set ups and such but I had a 180 BR before I got my 220ls and I can tell you for sure that you should have no problem pulling anyone behind that boat. I even had the 3.0 in it and I could still get myself out of the water on a slalom ski. I weigh about 180-185 and we would regularly have 3-4 in the boat and one behind it, either on skis or a board. My boat was stock set up so that is the only thing I can tell you.

Good luck and I am sure someone will be able to help you out. I think you would be making a big mistake if you went back to Glastron.

---

Austin, TX
2006 220LS

Ben,

 

Have you tried a 4-blade prop yet, or even a High 5?

These props are noted for their hole-shot.

---

2005 202 LPX
6.2L Bravo 1

Dale,

 I sure did, a Alpha4(Merc 4 blade) in a 14x20P.  I ordered a 14.5x18P Alpha 4 but I know I will be hitting too many RPMs with this blade at WOT.  My boat is useless as it is outfitted so I had to try something.  When using the Mercury website and putting in the weight instead of the RPMS and MPH it recommends this...  Any one else?

Ben Feldman:

Dale,

 I sure did, a Alpha4(Merc 4 blade) in a 14x20P.  I ordered a 14.5x18P Alpha 4 but I know I will be hitting too many RPMs with this blade at WOT.  My boat is useless as it is outfitted so I had to try something.  When using the Mercury website and putting in the weight instead of the RPMS and MPH it recommends this...  Any one else?

 Ben,

That is interesting.  I have an 07 180 carbed version with the Alpha 4 20p and it works great for pulling me out of the water (ski, and wakeboard) and Im a tad over 200 pounds.  I cant imagine that the gearing would be that dramatic of a difference, but I dont know.  Maybe try a SS 4 blade instead of the aluminum.    Also if u do drop down to an 18 or 19 p  then just dont go WOT.  ( I know its hard to do lol!)

Quote from http://www.moyermarine.com/faq/12.1.html "The most conservative suggestion: You could simply resize or re-pitch your existing prop. As a rule of thumb, decreasing the diameter or pitch by one inch will increase your RPM by approximately 200 RPM. Most prop shops are reluctant to decrease a prop more than one inch in diameter and one inch in pitch. However, such a combined change could get you as much as 400 additional RPM which could translate into 3 or 4 more horsepower." 

 You are reducing the pitch  of the prop and increasing the diameter which my cancel and you may not have a RPM WOT problem.  I have a 19SS with the 4.3L carb and I changed the prop from a 14X21 aluminum which hit the rev limiter to a 14 3/4X21 SS.   The only gripe I have is that the prop is always a little fast or slow for my likeings(I can be picky though).  As far as WOT is concerned, you should have a rev limiter or at least I do and the boat will say "DONT DO THAT!!" if your turning too many RPM's and not by flying push rods or anything like that .  Hope this helps.

Chris

---

2007 19SS w/4.3L Carb 1.87 Alpha 1

All,

 I appreciate the help.  I agree the diameter is going to come into play with this boat as a few have mentioned.  I'll post back my results with the 14.5x18P once I test it.  Below is the reposnse I received from Crownline's customer service.  

 "Your 180BR should easily pull a skier.  Assuming that you are not at an altitude above 2500’, I would suggest trying a 14.5 x 19p three blade aluminum prop.   Also, make sure your power trim is completely down until the boat is fully on plane. "

 

My brother has a Sea ray with the 4.3L carb with 1.81 and utilizes the 14x20" 4-blade and this thing is a monster.  It will literally rip the ski rope from your hand.  The gearing, 1.81 vs. 1.62, makes that much of a difference.  I will get him at WOT but a majority of the time we are barely at plane pulling tubes, skiers, and wakeboards.  I will definitely come back and post the results once I get the 14.5 x 18P  for future users.  Thanks again to everyone for their help!

I took the boat out today with the Alpha4 14.5x18P 4-blade prop.  A much improved holeshot.  I should have no problem skiing behind it now.  However, I can easily hit 5000 rpm and at 4800 rpm my speed has dropped to 45mph.  This is close to a 10mph drop from the 14.25 x 21p prop that I had turning 4600rpm.  Any thoughts?  This is going to get expensive trying various props.  PLEASE HELP....

Try a Mercruiser Highfive 19P 5-blade prop. I had a similar problem and his prop solved it. Great hole shop and 53mph at WOT. The prop is expensive, you may want to borrow one to test.

Brent,

Thanks for the suggestion.  I will give that a try.  However, it will probably be next Spring with the current weather conditions. Thanks again!

It sounds like Crownline's recommendation of the 14.5 x 19P would help out.  It would compromise the hole shot from the 18P slightly but shoult get better top end.  It should have significantly better hole shot than you experience with the 21P.

---

The 14.5x18P 4-blade should turn less RPM than the recommended 14.5 x 19P 3-blade recommended by Crownline.  I think my bigger issue is alum vs. stainless and the limited cupping that can be made into the alum prop.  Based upon my experience with this combo, there is no solution to accomplish what I'm looking for in a Mercury brand alum prop.  My expecations are not that high.....if it pulled like the 3.0L I had in my Glastron I would be happy.  I will not continually change props pending my use that particular day as described earlier in this thread.  If that is the case maybe this isn't the boat/combo for me.  I feel the 1.62 gear ratio with the 4.3L MPI is a big mistake on the part of Mercruiser.....they should keep the Alpha1 1.81 gear ratio found on most carb models......

I'm pretty sure it is the opposite.  The higher pitch prop (19P) will rotate at lower RPM top end.  The lower the pitch the more low end power but will spin too fast at the top end.  Kind of like leaving your car is 1st gear and flooring it.

---

All things equal I agree. However, we are comparing a 4blade 18P and 3 blade19P.  Every prop forum I've been on says you will loose 100-200 rpm.