OK what size 4 stroke Trolling Motor required????

madmans

Seaman Apprentice
Joined
Jun 29, 2008
Messages
43
FOR a 1983 22 foot Starcraft Ilander with a 120 mercruiser outdrive, I was going to use 245 horse (I have 2 and 4 stroke 25 s ) BUT I thinkin too heavy> What do yo uguys run? Thanx Mike
 

snowman48047

Petty Officer 1st Class
Joined
Jul 24, 2008
Messages
371
Re: OK what size 4 stroke Trolling Motor required????

My 82 Islander had a '92 150hp outboard with a 25hp Evinrude for trolling, both were 2 stroke. Worked like a charm. The difference in weight between the 2 and 4 stroke 25's won't be enough to make a difference as long as the kicker bracket is made to handle the weight.
 

1216bandit

Petty Officer 1st Class
Joined
Aug 18, 2008
Messages
214
Re: OK what size 4 stroke Trolling Motor required????

I have a 9.9 merc long shaft 4 stroke on the back of my 22' islander and it does the job just fine, as well as being rather light weight. I really didnt want too much weight hanging off the back of the boat, my choice. Your Islander is a deeper boat than mine and I am sure with the extra weight of the larger motor you will still sit with plenty of transom out of the water. As stated above, just make sure you get a good quality bracket thats up to handling the heft of the motor
 

Jlawsen

Master Chief Petty Officer
Joined
Apr 22, 2012
Messages
810
Re: OK what size 4 stroke Trolling Motor required????

In order to properly size a trolling motor you first need to determine what your minimum and maximum trolling speed requirements are. In most cases this is going to fall within 1.25mph and 4.5 mph. Using that for a starting reference you can see that anything over 9.9 hp is overkill and may not give you the minimum. If you can't get that minimum then you end up using trolling plates or dragging socks or buckets. That's not what I considered a good solution because it will cause excessive load on the gas motor and that will lead to premature failure. Many Merc 9.9 Pro Kicker owners are finding out that it's not the right option on boats 18' and under because of it's high thrust option. Yamaha discontinued their highly prized 8hp high thrust for this very reason. It was great on boats 20' and up but on smaller boats it had way too much thrust.

I have a boat with a 60hp main that I can troll down to 2.4 mph and it also has SmartCraft troll controll so I can troll at any speed above that. The range I needed to cover was 1.25 - 2.4 but I also needed to consider control of the boat. In my case I chose to go with an bow mounted electric because pulling a boat always gives far better control. Had I gone with a gas motor I would have chose a 6 hp 4 stroke motor and then added a panther remote steering unit and second set of throttle controls. This would have allowed me to use a single fuel source for both motor also.

When I chose the bow mount I also considered weight. The two options (electric or gas) weighed in very close to the same once you consider batteries, controls, etc.

Now I know you have two 25hp motors so this answer is probably going to have you scratching you head. I hope that is the case and I hope you consider evaluating your situation and consider selling the two 25's and opting for a smaller motor.
 

grzzzz

Petty Officer 2nd Class
Joined
Feb 23, 2010
Messages
135
Re: OK what size 4 stroke Trolling Motor required????

I have a 9.9 rude on my 18' holiday. At, idle or just above, it trolls about perfect, around 1.5 mph. So, I can't see anything bigger working?? It is a 4 stroke and weights 90lbs!!. It is nice to run off one tank but I do not feel comfortable trailering boat3 0151.jpg it hanging off the transom so I take it off and lay it inside the boat during transport. That is a pain!!

Grzzzz
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,368
Re: OK what size 4 stroke Trolling Motor required????

You didn't say under what conditions you want to operate.

Water conditions play a very large part in the selection process. While a 9.9 may be suitable for a small lake under most condtions, it may not give the desired results on river with a lot of current or a large lake where wind and waves may be an concern.

Undersizing a troling motor to where you use it 1/2 the time doesn't makes sense. Error on the side of too much. When push comes to shove I've never heard anyone say that they have too much motor. Only wishing they had more.

Regulate your trolling speed with prop selection, not HP
 
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