1800sr3 Prop Selection - Maxum Boat Owners Club

leeADAB · 04-28-2011, 03:28 PM

I have a 2004 1800sr3 with the 3.0L 135hp Mercruiser which about 4 years ago I changed the stock prop (21" Pitch Black Max Aluminium) for a shiny 21" Pitch Mirage Prop. Since the change I have always noticed that it took a while to get on the plane but once on went well. The Revs are low at WOT @ 4100 rpm with the boat loaded with 4 passengers.

I mainly cruise around in it and wakeboard so would just like it to pop onto the plane quicker than it currently does but I personally have no problems getting out of the water on the board when the boat pulls away.
I do make sure the boat is loaded right with people up front too to help get the nose down.

I am thinking that a 19" Vengeance or LaserII prop would get the RPMs up and help with holeshot but before I go ahead and find one I just wanted to know other thoughts.
I don't want to go down the route of trim tabs as the boat currently performs well apart from the initial hole-shot which really is all I need to improve.

The other option is to get my Mirage re-pitched to 20" but will the extra inch make a difference (no rude comments please!!) or is that the wrong prop fullstop?

Should I aim for the top end "4800rpm" oor just settle for getting between 4400-4800rpm?

Please can anyone offer some advice.....

Brianm · 04-28-2011, 04:03 PM

Not sure this will help but.....I have the 1900SR3, V6 190HP. When I bought it (new) it had the OEM 14x23, 3 blade Black Max AL prop. Boat performed great - nice hole shot, at WOT (light load) I'd get about 4700-4800RPM and @52mph (GPS). It would yank either of my grown sons out of the water on skis ok but with a "full" load it was, as you would expect, a bit slower out of the hole. My tech recommended a "prop guru" to me. The guy suggested that I try a 14.25x19, 4 blade AL (Solas) and wow.....with a medium load the boat just blasts out of the hole, I reached about 4900RPM and top speed was about 49mph(GPS). Have not yet been able to test it with the "full load" and a skier but am hoping to soon. Obviously, with a light load, I do have to watch the RPM to make sure I don't over rev. I was a bit skeptical about the dramatic drop in pitch but so far, so good. And, I DO notice the boat seems to handle better and is more responsive around the dock (slow speed) with the 4 blades. The "guru" also said that while I have to watch the RPMs when loaded lightly, I am not hurting the engine using the new prop with just the admiral and me (of course the mpg isn't as good as it would be with the OEM prop). Good luck.

leeADAB · 05-04-2011, 09:53 AM

Thanks Brianm for the input.

I have sourced a 19p which I should be able to test within the next couple of weeks but also have seen for sale an 18p Vengeance but at 13" diameter wondered if that is going to be too small or bring the rpms too high? The next size up in the Vengeance goes to 14" 19p diameter which sounds right?
My Current 21p Mirage prop is 14-3/4" (48-13702-A41-21P)

The other option is just to buy it and test but don't want to throw money at it if it is not suitable. Any suggestions?? Anyone else got a Stainless prop on an 1800sr3 with Mercruiser 3.0 135hp Engine?

Cheers...

seapuppy · 05-04-2011, 12:59 PM

i have a suggestion....go to a local prop shop....talk to them and they will let you try a few different props...you pay for the one that works....
the main thing is what is your WOT rpm???...that will determine the correct prop size...what does the owners manual state as wot range....

(wot= wide open throttle)..

SP

leeADAB · 05-04-2011, 02:31 PM

I don't think our chandleries would let us loose with an expensive prop just to test with. Worth checking though!! Not aware of any local prop shops. Then I'd also end up obliged to fork out hundeds of pounds on a new one. I plan to keep an eye out for a second hand one as we get screwed for "marine" parts over here.
Three or four second hand ones to test would cost less than one new one and then I can just sell them again.
As in my first post my current WOT rpm is currently around 4100 with the 21p Mirage and the engine states max rpm of 4400-4800 @ WOT!

I reckon the 19P will do the job I just hoped someone had changed theirs too on the same hull and engine to compare?

leeADAB · 07-17-2011, 07:55 PM

UPDATE..................

WOOOHOOOO!!! I have now bought and fitted a new Mercury Vengeance 14"x19" Pitch Propeller (48-16316-19). The difference is INCREDIBLE and it now feels like a completely different boat.
The WOT rpms are now hitting 4700rpm and the engine sounds great. Getting up onto the plane now takes literaly SECONDS!! For ages I've had to request people to move from the rear seats to get the weight forward - But when tested I had four people onboard and two of the guys were in the back seats and it was as if they weren't there. It really flies out of the hole. Can't wait to try wakeboarding behind it now!! The top end is still fast and the handling when turning seems much better/grippier too. The other thing I have noticed is that the back of the boat lifts out of the water more and the wake is so much cleaner - it always had a very turbulent wash at slow and fast speeds.
You can probably tell I am really pleased with my new chunk of stainless steel. HAPPY DAYS!!

seapuppy · 07-17-2011, 08:49 PM

well..congrats ...and thanks for posting!!!...wonderful news with the results of your prop instl...

SP

vfleck · 06-21-2021, 02:40 PM

I purchased a 2008 1800SR3 a couple of years ago and experienced the same issue trying to plane took too long. I saw this post from 10 years ago, great advise. It feels like a new boat. I bought a used Quicksilver 48-16316-19 for $140 on ebay in great shape. Great forum!!!

Wow! what a difference.

JGMID21 · 08-12-2021, 05:14 PM

I have a 2005 1800SR3 that I bought last year. With a moderate load has difficulty coming on plane. Some of this is improved with load shifting from the stern to bow, but it seems to need more than usual. I have a 14X21P 4 blade prop mounted and was thinking of changing prop to a 19P but not sure. Is this prop a 4 blade or 3 blade.

vfleck · 08-12-2021, 05:28 PM

Quote:

Originally Posted by JGMID21

I have a 2005 1800SR3 that I bought last year. With a moderate load has difficulty coming on plane. Some of this is improved with load shifting from the stern to bow, but it seems to need more than usual. I have a 14X21P 4 blade prop mounted and was thinking of changing prop to a 19P but not sure. Is this prop a 4 blade or 3 blade.

3 blade, I can't believe the difference. Super happy with Mercury Vengeance 3 Blade SS Propeller 14' x 19'. I bought a used earlier version Mercury-Mercruiser 48-16316A4.

Aselles · 09-06-2021, 03:43 PM

Hi
I have a 2009 1800 SR3 with 4.3l merc.
Troubles with hole shot. 4 adults in boat and it won’t plane if no one is in the bow. I would like better hole shot speed for water sports and ok with sacrificing speed.

I have a 14 x23P prop (3 blade ) on it now
Wot pushing 5000
Boat WOR range is 4400-4800
Max speed approx 43 MPH

So if I decrease pitch (for better hole shot) I think rpms will increase.
Maybe increase diameter?

I’m looking for suggestions and thoughts ?

mmwjr · 09-06-2021, 05:09 PM

There are other on this site with a similar boat to yours who will have a better suggestion but I would go to a 4 blade with a 14.5” diameter and either 19” or 21” pitch.

Aselles · 09-08-2021, 10:37 PM

Thanks
After speaking to others. The WOT rpm seems very high and decreasing pitch will increase it more.
Spoke to local marine shop and he suggested tach isn’t correct. Suggested to look behind the tach to see if it is set for correct engine. It wasn’t. It was set for a 4 cylinder not a 6 cylinder. Motor is running slower than indicated.

So doing some rough math. 5000 rpm multiplied by 0.666. (2/3) ( 4 cyl sparks 4 times per two revolutions and 6 cyl triggers 6 per two revolutions So off by a 1/3. )
Equals about 3300 rpm. The tach should be reading about 3300 rpm

So I now need to take boat for another lake trip to confirm my theory on WOT rpm’s and then select a prop. I feel better now knowing I can decrease pitch size from the 23P.

2004_3300_SCR · 09-09-2021, 02:36 PM

There we go ... just got on this thread, I was going to say, 14x23 3 blade doesn't give great holeshot on my 20 foot with a 350 MPI. It's adequate but not great. I went to a 23 from a 21 because I spun the hub on the 21 and the marina only had a 23 in stock. 14x21 3 blade prop seems to be perfect for that boat ... I had the prop re-hubbed and will be reinstalling it before going back on the water. With a 4.3 you're probably happy with a 19P ... I once had a Bayliner Capri 1850 / 4.3LX carb that was happier with a 19 than a 21. JMO, good luck!