Prop question???

bradford · #1 06-09-2016, 11:17 AM

Interested in hearing some opinions, got a 13 3/8 X 17 stainless on my 19 ' skiff with a 90 hp ETEC. Wants to porpoise above 4200 rpms trimmed all the way down, plus I think the max rpms I've gotten is 5100 or so, too low below the max which is like 5500-5800 i think. I want to switch to a 4 blade stainless for stern lift and hopefully stop the porpoising, plus drop down in pitch to get the rpms up.

Thinking about a BRP Rogue, Solas HR4 Titan, or Solas HR4 Rubex, in either a 13 1/2 X 13, or 13 1/4 X 15, what y'all think?

Plus if someone has one like what I'm looking for kicking around in good condition I'd be interested.

tsubaki · #2 06-09-2016, 11:34 AM

You may need to shim the motor.
My father had that problem with his 16V Ashcraft when he had the 90 horse on it.

West Marine.
http://www.westmarine.com/buy/t-h-ma...rctxoC47Dw_wcB
Here is a set on ebay.
http://www.ebay.com/itm/like/2719362...&ul_noapp=true

bradford · #3 06-09-2016, 11:41 AM

Those have crossed my mind, I'm running a TH Marine Atlas jack plate as well, and dont know if having too many "links in the chain" so to speak would be a bad thing?

tsubaki · #4 06-09-2016, 11:52 AM

You would think a 90 horse on a Skiff would not pose any particular problems other than possibly over turning the rpms.

bradford · #5 06-09-2016, 11:56 AM

Quote:

Originally Posted by tsubaki

You would think a 90 horse on a Skiff would not pose any particular problems other than possibly over turning the rpms.

Man, welcome to my world, try to do everything the right way and get kicked in the nuts doing it. lol

Thats me on the right.

tsubaki · #6 06-09-2016, 11:57 AM

shims and bolts are cheaper than a prop

bradford · #7 06-09-2016, 12:05 PM

Very true. but this is how it will work for me....

I'll buy the shims and bolts, unbolt the engine, install, SOME OTHER CRAP WILL HAPPEN, the condition will stay the same and I'll still need a different pitch prop.

OR

I'll buy and expensive as hell 4 blade, easy one nut installation, SOME OTHER CRAP WILL HAPPEN, whatever pitch I end up buying will be the wrong one no matter how many seasoned old salts agreed that it was exactly what I needed for the application, the boat will STILL porpoise.

tsubaki · #8 06-09-2016, 12:10 PM

Sounds like you been working out of my garage, none of that is new to me.

I just went and looked in the garage, thought I might still have the set we took off the Ashcraft when we swapped the 90 for a 50, but they aren't in there.

bradford · #9 06-09-2016, 12:20 PM

Quote:

Originally Posted by tsubaki

Sounds like you been working out of my garage, none of that is new to me.

I just went and looked in the garage, thought I might still have the set we took off the Ashcraft when we swapped the 90 for a 50, but they aren't in there.

I could have told you ahead of time and saved you the trip, lol

I do appreciate you looking, I have probably give or take 40 props, maybe half in decent to excellent condition, none for this application.

PS, Just for fun I went and counted, I have 38.

THEFERMANATOR · #10 06-09-2016, 01:02 PM

You havent seen porpoising till you've rode in mine. And for the record, the only thing shims do is allow more negative trim to make the engine push the bow down more and create MORE drag. Its an awfull band aid fix for a real problem. I still need to run mine again, but I put a permatrim on mine. I want mine to run properly, not with the engine plowing to bury the bow. A properly set up boat should run level with the engine nuetral trimmed or slightly negative trimmed. What happens if you raise the jackplate when its porpoising? Sometimes the engine is mounted to low, and causes it. The powertech scd4 is regarded as the ultimate anti porpoise prop by most, and has worked on quite a few CAROLINA SKIFF'S. It's an easy to tirn semi cleaver design. And the holeshot with them is out of this world. Give Ken at propgods a call, but I bet he reccomends a scd4 in a 17 pitch, and if you buy through him, it's $35 plus shipping to swap props.