What would I accomplish?

[tshaw84]

Having WOT issues with a 211 Liberator with 5.7 Merc.

Currently have 14.25 x 21

Would Would I gain...or lose...but going to 15x19?

Four winns tells me 14x19 came on it, but I recently found a nice prop used (15x19) and wanted to ask first, before I throw away money...

Thanks.

-Tom

 

[Bondo]

Re: What would I accomplish?

Having WOT issues with a 211 Liberator with 5.7 Merc.

Currently have 14.25 x 21

Would Would I gain...or lose...but going to 15x19?

Four winns tells me 14x19 came on it, but I recently found a nice prop used (15x19) and wanted to ask first, before I throw away money...

Thanks.

-Tom

Ayuh,.... Without knowin' the Rpms at Wot yer turnin', the question can't be answered,....

A 15"x 19" is an odd combo,...

 

[tshaw84]

Re: What would I accomplish?

I am getting 4000 rpms at 44mph Gps with my 14.25x21

The one on Craigslist the guy said he thinks it's 15x19..its a powertech M200OFS3R19P

 

[Sea Rider]

Re: What would I accomplish?

Wich are the min-max wot rpm parameters factory stated for that engine ?

Happy Boating

 

[tshaw84]

Re: What would I accomplish?

4600-4800 is what it says on the motor.

 

[Sea Rider]

Re: What would I accomplish?

4600-4800 is what it says on the motor.

If those numbers are the engine's stated wot parameters, you're excessively underpowered and severely lugging the engine at wot. Get a proper diam-pitch prop fast or you will end ruining the engine. Lugging an engine is like going up hill starting from base on third gear. Too much mechanical stress on pistons and crankshaft, definitely not good for engine. Check wich prop the engine manufacturer recommends as a prop starter and then go from there.

Happy Boating

 

[tshaw84]

Re: What would I accomplish?

14x19 is what Four Winns told me came with the boat.

14.25x21 on there now.

Was going to buy a 15(?)x19, but seems like that may not help? STill haven't heard anything from ptprops about that part number.......

 

[82rude]

Re: What would I accomplish?

if they are telling you 14x19p is what that combo requires id go with their advise over anybody elses.

 

[tshaw84]

Re: What would I accomplish?

I guess my main question is how much impact does the diameter have.

I can get a very nice 19p at a decent price, but diameter is about an inch larger.

 

[82rude]

Re: What would I accomplish?

it might cost you a few rpm.some say you really don't have to worry till over that amount ,some differ.its not like you have a 15hp and are asking it to swing a larger prop you have a 350cid motor with plenty of torque.do you have the room for an extra inch?actually solas amita,s are 15 3/10 x19 for that motor with alpha or bravo drives for example.

 

[jestor68]

Re: What would I accomplish?

Prop selection depends on what gear ratio you have.

The Merc prop selector agrees with Four Winns, in that it recommends a 14 X 19 in aluminum and SS using a 1.47 or 1.62 gear ratio.

It says that you should be able to turn about 4600 rpm and hit low 50 mph range.

I consider an inch of diameter as having about the same effect (on rpm) as an inch of pitch. Some experts consider the effect to be even greater than that.

 

[jestor68]

Re: What would I accomplish?

it might cost you a few rpm.some say you really don't have to worry till over that amount ,some differ.its not like you have a 15hp and are asking it to swing a larger prop you have a 350cid motor with plenty of torque.do you have the room for an extra inch?actually solas amita,s are 15 3/10 x19 for that motor with alpha or bravo drives for example.

I have those Solas props(14.5 X 19 vs 15.25 X 19) and have tested them on my 4000 lb boat. The larger dia prop runs 200 rpm slower with my 1.81 gear ratio.

 

[tshaw84]

Re: What would I accomplish?

Thank you guys for clearing that up! I will avoid that prop and continue looking for the 14x19.

I am having issues of reaching 4000RPM so I cannot afford to go up a size in diameter and risk not accomplishing anything.