PROP SELECTION ON MY MERCRUSER 140

[KC8OIT]

I WAS WONDERING HOW GOING TO A 21P FROM A 19 WILL AFFECT MY RPM AND MY ABILITY TO TOW A SKIER

 

[walleyehed]

Re: PROP SELECTION ON MY MERCRUSER 140

Drop rpm about 400 and will come out of the hole slower...

 

[KC8OIT]

Re: PROP SELECTION ON MY MERCRUSER 140

DOES THAT MEAN I WILL HAVE MORE TOP END? DO YOU THINK THE SLOWER TAKE OFF WOULD BE DRAMATIC,

 

[Dunaruna]

Re: PROP SELECTION ON MY MERCRUSER 140

Hi KC,<br /><br />It will lower your WOT RPM and adversly affect hole shot.<br /><br />Have a read of this (courtesy of walleyehed), its a draft but it will answer all your questions. After reading it you will realise its important to take all factors into consideration when choosing a prop.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=037140;p=1#000003 <br /><br /><br />Aldo<br /><br />edit: Sorry waleyehed, I was reading your draft and didn't hit refresh. Didn't realise you had already answered the post.

 

[Boatist]

Re: PROP SELECTION ON MY MERCRUSER 140

KC8OIT<br />I am one that thinks ok to run anywhere in your recommended WOT RPM range. I run a 17 pitch at 4600 RPMS and 35 MPH when I nee to pull a heavy load and do a lot of start stops. I run a 19 pitch at 4200 RPMS and 38 MPH for long trips at cruseing speed. 19 pitch 3 MPH highter top end better MPG but slower to get on plane. MY Boat is a 21 foot Closed Bow Aluminum Runabout with a 140 HP 3.0L I/O.<br /><br />However changing pitch with out knowing WOT RPMS can lug engine so bad you blow a hole in a piston, or over rev the engine until you loose a rod. Better find out your WOT RPMS before making any changes.

 

[cuzner]

Re: PROP SELECTION ON MY MERCRUSER 140

Do you have 3l engine? A 21p may be too much prop for that one.<br /><br /><br /> Jim

 

[KC8OIT]

Re: PROP SELECTION ON MY MERCRUSER 140

THANK YOU FOR ALL THE GREAT ADVICE, AS IT IS MUCH APPRECIATED.