2009 20HP Merc prop for trolling?

[northshoremb]

I just bought a 2009 20hp 4strk tiller for my 14' Sea Nymph Deep Water and Im very impressed at the speed she does now but trolls to fast.

I had a 1980 15hp Evinrude with stock 120psi per hole compression and a 10/9.25" pitch prop which only did 17mph last year. This year the new 20hp does 27mph on GPS which is a huge gain.

My only problem is it does 2-2.5mph at idle which is to fast for trolling worm harnesses and want to know what I can do for prop option to slow her down at idle and not lose top?

Does going to a smaller diameter prop mean less trust so it will cause it to have less out of hole power and bring trolling speed down?

The prop say 10 P on it and looks like I measured it out to 9.25"

 

[steelespike]

Re: 2009 20HP Merc prop for trolling?

Something was up with your 15. Should have been good for a solid 20 to 25
What trollig speed are you looking for?My guess is you won't lose much with a prop And you would lose top end and risk over reving if you don't pay attention.
I would try to lower the idle. You could consider a trolling plate or a drift sock.

 

[northshoremb]

Re: 2009 20HP Merc prop for trolling?

Ya it wasn't like the 15hp was wore out, still had stock compression and 40lb's lighter. Anyways I might just have to use my electric trolling motor.

 

[dkonrai]

Re: 2009 20HP Merc prop for trolling?

dont want to sound like a smart a** but, i troll at 2.3 mph, and trout fish alot. i now troll rapalas, and have ditched the dodgers/flashers due to my boat also not trolling slow.
just a thought. and yes we have been getting fish! have caught lm bass, and striped bass incidentially.
dino

 

[northshoremb]

Re: 2009 20HP Merc prop for trolling?

Ya that speed isn't bothering me for Salmon or Lakers but it is a problem for pulling worm harnesses here in the St.Mary's river for Walleye. You have to troll just faster .5-1mph then the current going down stream and in 30ft water still pulling 2-3oz bottom bouncers to touch. If I was going 2-3mph faster then the current I would need 6-8oz bottom bouncers to keep them at a 45.