Brand new Mercrusier 4.3L Aplha One Prop Damage

My "maiden voyage" of my new Sea Ray 185 sport yesterday led to me learning an invaluable lesson based on my inexperience: a). never completely put your faith in a depth finder; b). don't reverse over rocks with the trim down in shallow water!

I semi-shredded the stock prop. My questions are:

1. If I want to replace like-for-like (size etc) what should I buy? (I don't mind if it's OEM or alternative manufacturer). Aluminum is fine (I want to keep cost down).
2. Given that I have to replace the prop anyway, would I be better going for a 4 blade?

I have read the sticky and I am providing the following info. Any guidance is genuinely appreciated.

ESSENTIAL DATA REQUIRED
1) Performance issue you are trying to correct.
No performance issue. Just shredded my prop pretty badly. Considering 4 blade over 3 blade as I've heard it can improve ride, pick up, mid speed etc (although I was perfectly happy with my "unshredded prop.)"

2) Current prop manufacturer, model, aluminum or stainless as a minimum.
Stock prop on brand new Mercruiser Alpha One 4.3L 190hp

3) Current prop diameter and pitch (required).
Sorry, I am not sure how to measure this.

4) Wide open throttle RPM and speed with an average load (very helpful)
Not known.

5) Engine/drive make, model, year, and HP
Mercruiser Alpha One 4.3L 190hp, 2011.


6) Boat make model, year, length and weight
Sea Ray 185 Sport, 2011, 19.9ft, 2600lbs

Thanks in advance.
Picto

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

Picto said:

3) Current prop diameter and pitch (required).
Sorry, I am not sure how to measure this.

Click to expand...

Welcome to Iboats.
Depth finders only tell you what the bottom looks like while you are OVER that particular area, by the time a depth finder tells you you're too shallow, 99% of the time it's too late. Best thing to do is to get a depth chart of the area(s) you prefer boating, or have a friend ride along who knows the water and can point out where not to go.

As far as your prop pitch and size, that should be marked on the prop hub somewhere. I would expect the size for yours to be 14x17, or 14X19, maybe 14X21. I would recommend you find that size and match the new prop to it. As far as changing to a 4 blade, thats your call. Seeing as you didn't seem to have much problems with the 3 blade, why fix what isn't broken? The biggest advantage to going to 4 blade is more Umph onto plane especially with a full load of passengers and gear. If you feel as though you may be running th boat at capacity on a regular basis, you may want to consider a 4 blade.

Iboats has a nice selection of props for your ride at reasonable prices;
http://boatpropellers.iboats.com/Me...ers/?rotation=Standard&chart=77&engine_id=765

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

I semi-shredded the stock prop. My questions are:
If I want to replace like-for-like (size etc) what should I buy? (I don't mind if it's OEM or alternative manufacturer). Aluminum is fine (I want to keep cost down).
Given that I have to replace the prop anyway, would I be better going for a 4 blade?

Click to expand...

Ayuh,.... Find the part #, 'n size on yer shredded 1, it'll be along the side of the barrel, or under the Nut...
Then find yerself an inexpensive replacement in the same size...
Have a Prop Shop rebuild yer's,.. They might even have used/ rebuilt...

Once you figure out abit about boatin',...
Then go tryin' the 4 blade, or stainless, or 5 blade, or Whatever's...

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

My guess having the same engine and drive is it is a 14.25 x 21. Some put a 23 on it from the dealer but I haven't seen a 19 coming off the floor and def not a 17. Likely it was a Black Max or today's equivalent from Mercury and since it was aluminum, they are all pretty cheap. If you want to go real cheap try a Hustler aluminum prop. iBoats has some good sales on props some times. Consider yourself lucky that you didn't have an SS prop and limited the damage to just the prop. A good time to start carrying a spare with you as well as a wrench to remove the nut. A prop change is about a 5 minute job given your set up is new.

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

Thanks guys. Some good advice which I really appreciate. Thanks for taking the time to respond to my questions.

Picto

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

i have 2008 mercruiser 4.3l alpha1 190hp glastron gt 185xl, similar setup, came with 21-3 blade alum. just installed ss19 3 blade michigan prop and really like the differance. i always have a boat load pulling a tube and the extra low end is needed. top end affected very little. u might also consider a 4 blade 20 ss. u need a spare anyway, so give another style a try, and like the above responder suggested, rebuild the old prop. i have a 23 alum 3 blade for my spare and also the original shredded alum 21 waiting for rebuild if needed.

Re: Brand new Mercrusier 4.3L Aplha One Prop Damage

zzchipster said:

i have 2008 mercruiser 4.3l alpha1 190hp glastron gt 185xl, similar setup, came with 21-3 blade alum. just installed ss19 3 blade michigan prop and really like the differance. i always have a boat load pulling a tube and the extra low end is needed. top end affected very little. u might also consider a 4 blade 20 ss. u need a spare anyway, so give another style a try, and like the above responder suggested, rebuild the old prop. i have a 23 alum 3 blade for my spare and also the original shredded alum 21 waiting for rebuild if needed.

Click to expand...

Thanks man. I checked my prop and it's a 19 (as standard). I also will often have a pretty full boat (my wife and I, my two teen sons and my 7yo daughter as the typical crew). Towables and wakeboarding. Sounds like the 19 works for you, I have no issues with it, so I'll stick with it for now. It's currently being rebuilt locally. I am going to buy a 4 blade as a spare and just see how it rides. So you recommend going for a 4 blade 20?