Trolling with a Mercruiser

sandan5

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May 23, 2012
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We have a 1996 Maxum, 20 ft. long, 3.0 4 cyl and want to troll for fish, and are considering 3 options:
1) Idling down the engine 2) Installing a trolling plate on the outdrive 3) Mounting our Mercury 110 outboard on the stern or an electric motor somewhere on the boat

Some of our considerations: We have heard that running the I/O at low rpm's for an extended period of time isn't advised........trolling plates aren't very effective........not sure we want to drill holes in our boat, which would be needed to mount a kicker

Any thoughts or advice?

Thanks
 

Bondo

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Apr 17, 2002
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71,169
Re: Trolling with a Mercruiser

Ayuh,.... I slow my trollin' speeds with over-sized trim tabs, 'n tossin' drift socks out the side of the boat...

Of the 2000 hours on my motor/ drive, 90% is trollin'...
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Re: Trolling with a Mercruiser

What speed you want to troll at? I do most of my trolling at 6 knots, about 1400rpm. At normal idle speed (650rpm) the boat's only doing 2.7 knots, way too slow for trolling.

Who told you running I/Os at low speed wasn't advised? Load of BS!!! Less of a problem with a 4 stroke I/O than a 2 stroke outboard... Those 3.0 litre engine's will idle all day with no problems.

Chris......
 

tpenfield

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Re: Trolling with a Mercruiser

The bigger issue is if at the lowest idling speed the boat will be going slow enough. My boat would do 5 mph at idling speed, and no slower.

if it matters to be able to go more like 2-3 mph, then you may want a trolling motor.
 

Bondo

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Re: Trolling with a Mercruiser

What speed you want to troll at? I do most of my trolling at 6 knots, about 1400rpm. At normal idle speed (650rpm) the boat's only doing 2.7 knots, way too slow for trolling.

Who told you running I/Os at low speed wasn't advised? Load of BS!!! Less of a problem with a 4 stroke I/O than a 2 stroke outboard... Those 3.0 litre engine's will idle all day with no problems.

Chris......

Ayuh,.... Freshwater fishin' is usually done at below yer saltwater fishin' speeds...

I run down to sub-1 mph sometimes for Walleyes, 'n up to 2.5 mph for salmon....
 

sandan5

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May 23, 2012
Messages
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Re: Trolling with a Mercruiser

What speed you want to troll at? I do most of my trolling at 6 knots, about 1400rpm. At normal idle speed (650rpm) the boat's only doing 2.7 knots, way too slow for trolling.

Who told you running I/Os at low speed wasn't advised? Load of BS!!! Less of a problem with a 4 stroke I/O than a 2 stroke outboard... Those 3.0 litre engine's will idle all day with no problems.

Chris......

sounds good.....I will try the I/O and see if I can maintain the desired trolling speed

thanks
 

sandan5

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May 23, 2012
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Re: Trolling with a Mercruiser

I like those options much better than what I was considering

thanx
 

mike165

Petty Officer 2nd Class
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Apr 14, 2011
Messages
196
Re: Trolling with a Mercruiser

Depends on the lures,5KPH for Tassie Devils,2KPH for Fenders trolling for trout in fresh water
 

wrestling coach

Petty Officer 1st Class
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Jun 27, 2011
Messages
210
Re: Trolling with a Mercruiser

Sandan,
I have two boats that I troll with extensively. They both catch fish. Walleye fishing mostly where I'm trying to achieve 2.0-3.0 SOG (speed over ground) on my GPS. One boat is an 18' Lund with a 90hp Johnson 2 stroke. It has a trolling plate. The other is a 19' Grady White with Merc 470 IO (Bond O's favorite engine).
I have found that the trolling plate slows my boat down too much in most cases. I rarely use it except for specific boat control situations like the current of the upper Niagara River. In the open water of Lake Erie I'm on engine only.
My IO is on the St Lawrence River/Lake Ontario where it is used for trolling for Walleye,Northern Pike,Bass and the odd Muskie. It does not have a trolling plate and I am able to hit my trolling speeds (2.0-3.0) SOG with no problem. The engine is always in good tune with fresh plugs,cap and rotor etc. I did upgrade it to an electronic ignition (Pertronix). I felt all of these would help me achieve my trolling speeds. I have turned the spec idle speed down and I can control my speeds up and down for hours without any problems. Each boat is different and I would suggest you try WITHOUT the trolling plate first and try to get it to work.

Dennis
 

sandan5

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May 23, 2012
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Re: Trolling with a Mercruiser

Hadn't considered those options......sound good to me......

thanks
 

sandan5

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May 23, 2012
Messages
13
Re: Trolling with a Mercruiser

Coach.....

You obviously have a wide range of trolling experience......I would prefer to make it work without the trolling plan and will try it out when they're bittin'

thanks
 

sandan5

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May 23, 2012
Messages
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Re: Trolling with a Mercruiser

we barely have our feet wet for trolling fishing.....will consider these options down the road.......thanx
 

Thalasso

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Jan 18, 2011
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2,879
Re: Trolling with a Mercruiser

Get yourself a drift sock a large one and you will be good to go.
 

Davcar

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Aug 22, 2003
Messages
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Re: Trolling with a Mercruiser

Our boat is a 165 I/O. For years we trolled on quiet Canadian lakes for Walleye with a Happy Troller plate. Don't ask me about the times I took off without raising it first. Anyway, we never cared much about the speed other then it was nice and slow and quiet. The past year my son and I started getting into Salmon fishing on Lake Ontario. With the waves, wind and speed required, 2.5mph +/- the trolling plate was not the hot set up. I had to use 1000-1100 rpm to get the speed we wanted.(idle was about 600) but steering was a constant fight. A little wind and it was turning sometimes lock to lock to try and keep it straight. I may still get trolling bags but 1/2 way thru the season I made a change that really helped. The trolling plate had notches to either hold it up or all the way down. I cut new notches halfway between. Now a quick pull of the string and it'll go down and lock down at the 45 degree angle and speed can be easily achieved and regulated but more importantly steering is vastly improved. Want to drop the speed back down for slow walleye trolling pull the string and let the plate go all the way down.
 

fishrdan

Admiral
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Jan 25, 2008
Messages
6,989
Re: Trolling with a Mercruiser

I use a Troll-A-Matic on my 140HP Mercruiser and it will crawl along at less than 1MPH, at idle. I'm usually just off idle trolling (700-800RPM) to get the lures running properly.

As Davcar mentioned, diminshed steering is the biggest issue I've had running a plate,,, and over correcting to get the boat back on course. Though, it's not a concern until the wind and waves kick up, and I've learned to add a bit of throttle to correct the boat's heading. Not a biggie is you have others onboard to tend rods and land fish, big PITA if you're fishing alone and trying to land a fish while the wind is blowing the boat all over the place.
 

elkhunter338

Master Chief Petty Officer
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Jun 27, 2009
Messages
818
Re: Trolling with a Mercruiser

I am pleased with my happy troll, that is spring loaded on the bottom half to prevent damage if you forget to put it up.
Mine is on a 3.0 merc, works great just nice to have two people to get it up. 1 to pull the cord the other to shift the boat back into gear. trolling plate does not release if you are in gear.
 

jimbo_jwc

Ship Happens
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Dec 19, 2010
Messages
633
Re: Trolling with a Mercruiser

I get down to 2.2 mph with 3.0l Mercruiser on 19.5 ' Idle 600 RPM and kicker at Idle will take to a little over 1MPH on my Garmin . Kicker is 4.5 Hp Johnson mounted to swim entrance platform on Inland lake light breeze . Great Lakes with wind drift I have to Idle up . Speeding up is easier and more cost per hr than trying to slow down when finding what fish like .
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Trolling with a Mercruiser

Another way to get the troll speed down without adding plates and socks is to change the prop to one with less pitch. If your running a 17", for example, and at 650 rpm doing 2.5 knots, then changing to a 13" will drop that speed down to 1.9 knots. You just need to be aware that at higher throttle positions the engine will run quicker than 'normal'... Easy to go too far over the top recommended RPMs...

Chris....
 
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