prop help needed

eyellaw

Recruit
Joined
Sep 24, 2020
Messages
2
i have a 1995 lund tyee 1950 magnum GS with a 200hp evinrude vindicator with a 14 1/2x19 steel prop. with a full fuel tank (60 gallons) and complete fishing setup, W.O.T. rpm is 6500, i am in south dakota (if it makes any difference). i was told the target range is 5500-6000. there are not any loaner props available in my area that i have been able to find to try before forking the cash out to buy the "correct" prop. i am curious if a 14.2x21 wont get me low enough, or if a 14.2x23 will be too low? just looking for good input before i finally make my own bad decision.
 

WesNewell

Chief Petty Officer
Joined
Jan 3, 2018
Messages
497
First thing I'd do is check the tach for accurate reading/setting. If not. Then correct and re test. Check manual for rpm range. Iboats list 5500 rpm for that engine. Altitude will affect performance. State doesn't matter. if you don't pull skiers, and your tach is right, then you would probably want to go to a 23P.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Is that motor an Etec 200 HP version ? If so, the wot range is 5000-6000 rpm. So 500 wot revs more than its max rated for. Try a 21 pitch or send current prop to a prop shop and have it repítched to 21, surely much less in cost.

Happy Boating
 

eyellaw

Recruit
Joined
Sep 24, 2020
Messages
2
Well the tach operates smooth with no bouncing, so I am guessing its accurate. Is there a way to check the true accuracy of the tach? The guy I bought the boat from said he pulled skiers and tubers with it so that may explain the 19p prop. I listed the state as elevation reference not "state pride" lol.
How many rpms will I drop going to a 21p and 23p? Is it best to run at the top end of your suggested rpm range?
 

WesNewell

Chief Petty Officer
Joined
Jan 3, 2018
Messages
497
It should operate smooth on all settings. that doesn't mean a thing. My brother bought a hew ranger RT188 in 2014 that was set wrong from the factory. It operated smooth too, just ~800 rpm over the actual rpm. He didn't find it for 3 years, after trying to re prop. Yep, if po pulled skiers, then that's why he had a low pitch prop. usual rule of thumb is 200 rpm per one inch in pitch. So going from a 19p to a 23p would lower rpm about 800 rpm, but that can vary depending on prop. As for the rpm you want, my thought is max with lightest load. Mid range with normal load. Others may think otherwise.
Elevation on SD lakes can vary from 966' to over 7000'. For every 1000' you lose ~3% of hp.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
How many souls were on board when the tach read 6500 wot revs ? is that the usual number of souls that plan to go boating with ? As previously tested a 21 pitch should put the motor to rev around max 6 K wot revs. A 200 HP motor should achieve way more than just 200 revs per + 1 pitch specially being a medium light boat with a powerful motor, a 23 pitch will lower the wot rpm too much. Only a wot run as usually loaded will tell. The only way to check any tach accuracy is with a new tach..

Happy Boating
 
Top