Need help on a propeller replacement

[ROCKFISHTED]

Hi,

I am new to power boats and have purchased a 21 ft boat with a 2004 150 Yamaha 4 Stroke Outboard. The aluminum propeller has been damaged and I would like to replace it myself however there are no markings on it to indicate its diameter and pitch. I have found a 3 blade propeller on iBoats that has a pitch of 19 and is 14 1/2 " diameter. I have watched a couple of youtube videos and replacement looks pretty easy however I want to make sure I am purchasing the right prop. I don't need to go real fast or get on place real fast. Just looking for standard propeller. Any help is appreciated.

[ROCKFISHTED]

here is the one I was looking at

Quicksilver Black Diamond Aluminum Boat Propeller #QA1916X for Yamaha 150 HP Outboard 2004 & Newer F, 4-Stroke - iboats.com

[Jason2tpa]

Quicksilver Black Diamond Aluminum Boat Propeller #QA1916X for Yamaha 150 HP Outboard 2004 & Newer F, 4-Stroke - iboats.com

If you plan on primarily using the boat inshore I suggest a stainless steel prop. Otherwise, hit hard bottom once with aluminum and you'll be replacing/reparing again. SS is more expensive, but in the long run it's less expensive compared to aluminum.

Removal and installation of the propeller is very simple, even for the new boaters such as yourself. Your owners manual details this procedure. If you don't have the owners manual for your engine they can be downloaded online for free. Service manuals can be downloaded for a small fee.

And don't be frustrated if it takes you testing a few props till you find the right one. Propping is an art form, not an exact science. Use the information Townsend provided as a guide, a starting point. If you start with a 19" pitch, but the engine will not reach top end of rpm spec at WOT, then drop down to a 17". Rpms to high with the 19", go up to a 21". Need a better hole shot and bow lift, try a 4 blade. The options are endless.

[Jason2tpa]

If you plan on primarily using the boat inshore I suggest a stainless steel prop. Otherwise, hit hard bottom once with aluminum and you'll be replacing/reparing again. SS is more expensive, but in the long run it's less expensive compared to aluminum.

Removal and installation of the propeller is very simple, even for the new boaters such as yourself. Your owners manual details this procedure. If you don't have the owners manual for your engine they can be downloaded online for free. Service manuals can be downloaded for a small fee.

And don't be frustrated if it takes you testing a few props till you find the right one. Propping is an art form, not an exact science. Use the information Townsend provided as a guide, a starting point. If you start with a 19" pitch, but the engine will not reach top end of rpm spec at WOT, then drop down to a 17". Rpms to high with the 19", go up to a 21". Need a better hole shot and bow lift, try a 4 blade. The options are endless.

[scofflaw]

The markings will be on the butt end close to the splines

[pstephens46]

The markings will be on the butt end close to the splines

Yes, remove the prop and you will see the info for the current prop. I have a similar setup to Townsend and F150 and use a SS 18 pitch prop. 5900 rpm.