Prop Exchange?

[cpostis]

Those black ones SS?

That test wheel would be nice but if different manufacturers with the SAME #'s will yield different RPM's, kinda pissing in the wind me tinks..

BTW, you get an "atta boy" for your diligence today Chuck!!

Well, that's what the dealer said? I guess other factors in the design would make a difference. The props are all SS.
Your whole statement, I hope you're not thinking the test wheel has anything to do with prop selection, do you? I know you're smarter than that! The only thing the test prop does is puts the designed load on the motor.

Just looked through Yamaha's Rigging catalogue. A lot of information on props, good or bad?

Jason,
Here's a link to the catalogue. Click on the contents at the left side of the top bar, and then click on propellers in the table of contents. Thumb through the pages if you like.

http://yamahaoutboards.com/catalog/2016/MRP/

I do have an ulterior motive researching all this, I plan on changing my 4 blade prop to a 3 blade. I know I could get better fuel mileage and top end speed. Not sure I want to reduce my bight, especially when chasing down schools of fish, following seas, and entering the sometime vicious Sebastian Inlet. We'll see!

[TownsendsFJR1300]

Well, that's what the dealer said? I guess other factors in the design would make a difference.
Your whole statement, I hope you're not thinking the test wheel has anything to do with prop selection, do you? I know you're smarter than that! The only thing the test prop does is puts the designed load on the motor.

I've never seen one (nor used one) and know it puts a load on the engine safely... Checking WOT timing (again reading on this forum), HAS TO BE done on the water under load- NO load tools

The way this thread reads (what I interpet), Jason wants it to figure out WHAT PROP to pick. Since reading this thread, it sounds like yes, it helps pick the proper prop.

He's already posted the engine runs up to the lower end of the RPM range (IE-No engine issues). So why would he need this tool then?

As I've posted before, mine was under propped (when re-powered) and the prop shop sold me what they thought was good, and it was dead nuts perfect.

Jason, are you aware of the above post before you start shipping that tool back and forth??

Reading back to page 2, RB and 99yam both mentioned using the test wheel

[pstephens46]

Test wheel just confirms motor is 100% then moving to next logical step.

My gut is still a 21 pitch is too much for his sled..

[cpostis]

I've never seen one (nor used one) and know it puts a load on the engine safely... Checking WOT timing (again reading on this forum), HAS TO BE done on the water under load- NO load tools

The way this thread reads (what I interpet), Jason wants it to figure out WHAT PROP to pick. Since reading this thread, it sounds like yes, it helps pick the proper prop.

He's already posted the engine runs up to the lower end of the RPM range (IE-No engine issues). So why would he need this tool then?

As I've posted before, mine was under propped (when re-powered) and the prop shop sold me what they thought was good, and it was dead nuts perfect.

Jason, are you aware of the above post before you start shipping that tool back and forth??

Reading back to page 2, RB and 99yam both mentioned using the test wheel

Scott, Jason has posted on another thread his performance now. this is a partial quote from his post.

"When I purchased boat/motor from previous owner it came with a 21" pitch SS prop. The dry weight of the hull is 1100 lbs, 17' mod-vee bay boat. Running at WOT, 1/4 tank of fuel, and no other necessary weight, i'm turning 4400 rpms."
Jason is aware.

A link to this thread is:

http://www.yamahaoutboardparts.com/f...n-th27635.html

[TownsendsFJR1300]

Scott, Jason has posted on another thread his performance now. this is a partial quote from his post.

"When I purchased boat/motor from previous owner it came with a 21" pitch SS prop. The dry weight of the hull is 1100 lbs, 17' mod-vee bay boat. Running at WOT, 1/4 tank of fuel, and no other necessary weight, i'm turning 4400 rpms."
Jason is aware.

A link to this thread is:

http://www.yamahaoutboardparts.com/f...n-th27635.html

Ok, I remember reading that awhile ago. I'm not keeping up with the multiple threads obviously.

But, yes, that makes sense... Thanks..

I'm getting my popcorn now, watch and learn

[Jason2tpa]

Hey boys. First, big thanks to cpostis for prop shopping. Shocking they didn't have more selection for what I'm looking for considering how many props in your picture. They have a lot.

From the research I've done, a used prop in great condition only sells $75-100 less than a new one. My prop, which is now on eBay & craigslist, is listed for $175. Same prop sells new for $250 by online distribs. It's highly likely my prop will sell for asking price considering its condition and how few used props like it are available. So in the end, after purchasing a new one and eventually selling the 21" I'll really only be spending $100-150. Excluding the $35 hub kit.

pstephens46 is correct...

Test wheel just confirms motor is 100%

The specific topic of this thread has jumped off topic. Townsend referenced a different thread of mine addressing prop performance & engine performance. The thread is here if you want to read up:

http://www.yamahaoutboardparts.com/f...n-th27635.html

99yam and rodbolt were both adamant about checking engine with test wheel before purchasing a prop. That way I could rule out the slim possibility I was turning lower rpms at WOT due to engine problem. And you know what, they are not wrong. Am I 100% certain the lower rpms are NOT being caused by the engine, verses over-propping? No, not 100%. Only because I haven't checked engine with test wheel. But neither of them have been on the water with me in the my boat. They are only suggesting due diligence. However, many factors point to the lower rpms being caused by the prop. NO factors have pointed to an engine issue.

The factors pointing to over-prop? Prior to me installing new carb kits, cleaning all jets, etc, and installing a new fuel pump, filter, and fuel hose, I was turning 4400@WOT. After performing all of the former, the engine turned 4700@WOT. Better, but still below the upper end of spec rpms. If I had and engine issue (compression related or likewise), I doubt I would have seen this increase in rpms.

Another factor pointing to over-prop, which had me convinced even prior to cleaning carbs and fuel components, was the scale of pitch props offered for my motor. The most common lowest was 13, the most common highest was 23. Mine is 21".

Simple mathematical logic, including the use of 1 inch of pitch = 150-200 rpms, points directly to over-prop. Motor isn't under-prop, motor isn't even turning mid range of rpm spec. The 21" prop is at the high end of available pitch props for motor, only one size higher is available. However, 7 smaller pitch sizes are available for motor.

Combine all of the above with the feedback I've received from Admiral. AND the numerous web prop selectors, where you enter in type of boat, motor, current rpm@WOT, and current prop pitch. All of these selectors spit out the suggested props with pitch between 14 and 19. None suggested 21".

Needless to say, I'm fairly confident this is an over-propped boat. Not a poorly performing motor. We will all know the result as soon as I locate the new prop I want.

Stay Tuned !!