20hp manual vs 15hp electric on a 16ft aluminum v hull

zackyholdem

Recruit
Joined
Apr 13, 2015
Messages
1
Hi All,

Purchased a new 20hp nissan 4stroke long shaft tiller this year from a dealer that was old stock (couple of model years ago). Long story short motor has 13 hours on it and has been back to the dealer for service multiple times in the 3 months that i have had it for significant engine work including having to split the block open. The dealer and I both agree that i have a lemon and they are willing to allow me to do a full value trade in on it for a new motor of my choice of equal value or more (i pay price difference if it is more expensive)

The boat that i have it on is a 1976 starcraft 16ft deep v aluminium, with a hull weight of 650ish empty. With the 20hp on it with myself and fully loaded with gear (trolling motor, battery, poles tackle) it would do 21 mph at WOT. I mainly use the boat for local lake fishing in Michigan and trolling for walleye and salmon in rivers and pierheads of lake Mi and lake erie in calm water days.

The top end speed of 21 ish mph is more than enough for me as i don't really do any long runs. The two motors I have a choice of getting are a new 2015 tohatsu 20hp manual (same motor as i had before) or a new 2015 15hp tohatsu electric.

My question is i run electronics so it would be nice to have an alternator and electric start to keep the battery charged (i use the same battery for trolling motor as i do for electronics). I wouldn't mind sacrificing a few mph top end to switch from the 20hp manual down to the 15hp electric. Being that they are the same engines just carbed and tuned differently i'm assuming i will lose a little top end and a little lower end but i don't think i will see huge performance differences. Also im thinking the 15hp will let me go slower for trolling (good thing!) vs the 20hp which only let me get down to 1.7ish mph)

Can i go with the 15hp electric and get the type of performance that i think i will get out of it? or should i expect more severe performance losses? Also i dont want to spend any more money on motors so these are my two options.

Thanks in advance, Zack
 

fishin98

Chief Petty Officer
Joined
Nov 28, 2009
Messages
521
The electric start 15 sounds like a good deal, you may lose 2-3 mph top speed, but what you gain in battery re charge plus a slower trolling speed makes it look like a good choice. I'm considering a similar motor for my 14ft Alumacraft Lunker redo.
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,201
Also, keep in mind you can intententionally underprop a boat to make it troll slower, just have to watch out on the top end that you aren't over revving it. (could also use trolling socks..)
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,665
1 - you are going to want the 20 hp.

2 - You are going to need to run long and hard ( hours ) for that 15 to put any charge back into your battery.

I would go with the 20 hp, and get a second battery if you need more than one battery can give you.
 

WIMUSKY

Moderator
Staff member
Joined
Sep 26, 2009
Messages
19,798
I would go with the 20 too. I'm assuming you're using a deep cycle.....
 
Last edited:

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
20hp

You can probably add a charging coil to the 20.
 
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