# Trolling with 115HP Mercury ????



## Chuck Smith (Mar 22, 2016)

Are there any ill effects from trolling with my 115HP merc?
I don't want to use the big motor if it isn't good for it.

Trolled the other day with my Terrova in calm water but don't think that will be do-able in rougher water.
Have been considering looking at a 9.9HP 4 stroke for trolling on the big lake.

Any thoughts / comments?


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## ESOX (Nov 20, 2000)

Chuck Smith said:


> Are there any ill effects from trolling with my 115HP merc?
> I don't want to use the big motor if it isn't good for it.
> 
> Trolled the other day with my Terrova in calm water but don't think that will be do-able in rougher water.
> ...


I troll with a t8 kicker, I like not putting the hours on the expensive big mill.


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## Jimbo 09 (Jan 28, 2013)

You will be a lot happier with a 4s kicker. A lot quieter, sip fuel and keeps the hours and wear off the main. Plus you can get back in if your main dies.


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## bowhunter426 (Oct 20, 2010)

I troll with my 150 4S. The cost of rigging a kicker was over 1/3 the purchase price of the 150. For me the expense was not worth the savings. I get out 3-4 times a month for a 3-4 hours at a time. Average less than 1 gallon an hour when trolling. I have considered a kicker for that extra get back security, but never to save gas or reduce wear on the main motor.


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## Jimbo 09 (Jan 28, 2013)

I guess I assumed the 115 was a two stroke. Two strokes are no fun to listen too or smell all day. If the 115 is a 4 stroke it probably won't be to bad to troll with if it gets the boat slow enough for your needs.


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## Chuck Smith (Mar 22, 2016)

ESOX said:


> I troll with a t8 kicker, I like not putting the hours on the expensive big mill.





bowhunter426 said:


> I troll with my 150 4S. The cost of rigging a kicker was over 1/3 the purchase price of the 150. For me the expense was not worth the savings. I get out 3-4 times a month for a 3-4 hours at a time. Average less than 1 gallon an hour when trolling. I have considered a kicker for that extra get back security, but never to save gas or reduce wear on the main motor.


I can't troll slow with the main. At idle about 2.5 MPH???
Wasn't sure how extended slow trolling affected the bigger 4 stroke motors.
Have a drift bag I thought about hooking to the winch eye but don't like the thought of the line breaking and the bag ending up in my prop.
What are the best speeds to troll for the different species?
I also was considering the cost of the 4s kicker.


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## bowhunter426 (Oct 20, 2010)

Chuck Smith said:


> I can't troll slow with the main. At idle about 2.5 MPH???
> Wasn't sure how extended slow trolling affected the bigger 4 stroke motors.
> Have a drift bag I thought about hooking to the winch eye but don't like the thought of the line breaking and the bag ending up in my prop.
> What are the best speeds to troll for the different species?
> I also was considering the cost of the 4s kicker.


I pull bags on each side of the boat off a side cleat and can get the boat down to 1 mph sog. Inspect the straps before use and you don't have much to worry about. For salmon I run without bags and run around 2.5 mph SOG as well. The newer 4 stroke large motors can run all day at idle with no issues.


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## Chuck Smith (Mar 22, 2016)

bowhunter426 said:


> I pull bags on each side of the boat off a side cleat and can get the boat down to 1 mph sog. Inspect the straps before use and you don't have much to worry about. For salmon I run without bags and run around 2.5 mph SOG as well. The newer 4 stroke large motors can run all day at idle with no issues.


How large bags do you pull?


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## bowhunter426 (Oct 20, 2010)

Two 18" bags on a 19' boat.


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## Chuck Smith (Mar 22, 2016)

bowhunter426 said:


> Two 18" bags on a 19' boat.


No problems with the bags rubbing on the sides of the boat?


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## ebijack (Apr 20, 2009)

bowhunter426 said:


> The newer 4 stroke large motors can run all day at idle with *no issues*.


Did a salesman tell you that? I can state from my background.
There is no "new" technology that can improve the problematic condition of idling with a 4 stroke engine. Fuel injection is what really increased 4 stroke engine life. Injection did help at idle some, with less unburned gasoline getting past the rings and diluting the engine oil. Even more so at higher speeds. Main reason 4 stroke engine oil change times were lengthened/increased, due to fuel injection replacing carburetors.
Excessive idling in gear with a 4 stroke shortens the engine life/total hours. Long periods of idling in gear, is the worst condition on any 4 stroke engine. For maximum engine life.
Now, if you use your "bags", troll at or above 1200 RPM you would be much better off for engine life expectancy. Fuel injected or carbureted. There is a difference between just idling, and idling in gear for trolling. Idling in gear is the worst condition.
Now will most ever see a problem. No, because most don't keep their boats all that long. 2500 + hours.
2 stroke engines do not have that "condition/problem".


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## bowhunter426 (Oct 20, 2010)

They occasionally rub due to currents and such but there are no marks from it. 



ebijack said:


> Did a salesman tell you that? I can state from my background.
> There is no "new" technology that can improve the problematic condition of idling with a 4 stroke engine. Fuel injection is what really increased 4 stroke engine life. Injection did help at idle some, with less unburned gasoline getting past the rings and diluting the engine oil. Even more so at higher speeds. Main reason 4 stroke engine oil change times were lengthened/increased, due to fuel injection replacing carburetors.
> Excessive idling in gear with a 4 stroke shortens the engine life/total hours. Long periods of idling in gear, is the worst condition on any 4 stroke engine. For maximum engine life.
> Now, if you use your "bags", troll at or above 1200 RPM you would be much better off for engine life expectancy. Fuel injected or carbureted. There is a difference between just idling, and idling in gear for trolling. Idling in gear is the worst condition.
> ...


So idling a 4 stroke is bad, yet Mercury sells a troll control module for the specific purpose of low speed trolling which maxes out at 1000rpm. There are many guys out there running the new mercury 4s with 1000 plus hours using it for trolling. 70 hours last year on my 150 and the oil came back from Blackstone clear of any fuel. I believe your experience and opinion no longer align with modern 4S outboard engineering and manufacturing. 

And no it wasnt a sales guy, engineers from both Mercury and Yamaha have told me.


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## ebijack (Apr 20, 2009)

" I believe your experience and opinion no longer align with modern 4S outboard engineering and manufacturing. "

Yeah, your right. My 30+ yrs building engines, testing engines for future engine development (both 2 and 4 stroke) and building prototype vehicles is outdated. Also transmissions, rear ends, etc etc.
I stand by my statement "There is no "new" technology that can improve the problematic condition of idling with a 4 stroke engine." When comparing a 2 stroke to a 4 stroke.
Believe what you want.

"And no it wasnt a sales guy, engineers from both Mercury and Yamaha have told me"

You sure they were engineers? Where did you talk to them?
I'd bet the Merc guy could not tell you where the injection system for the Opti's was designed/developed/tested. Prior to Merc getting the data, then adapting to their Opti's.

Gm had 3 cyl and V-6 2 strokes that met 1996 automotive emission standards in 1989. Just couldn't get the cat coverters to last 100,000 miles per GOv. regulations.
Again, believe what you want. Doesn't matter to me.


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## bowhunter426 (Oct 20, 2010)

ebijack said:


> You sure they were engineers? Where did you talk to them?


The Merc guys were at the headquarters in Fond du Lac and Yamaha was at a trade show. 

If idling where massively detrimental to the motor, manufacturers would not be selling devices like troll control and factory 5+ year warranties. The controls systems are phenomenal on the new motors At 70 hours, 60 of which was at idle speeds, I had no abnormal fuel quantities in my oil. Not even close. With 100 hour change intervals the chance or rogue fuel breaking down the oil is near impossible on a well maintained system.

For a 10k-12k outboard, my opinion is that it does not make fiscal sense to spend 1/3 of purchase price of the motor to "save" the motor. The 4k I was quoted could be invested and in 10-15 years will have grown to the point to either easily cover a new powerhead or a repower. If the kicker were closer to 10% of the outboard cost it makes since


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## coralee (Jan 18, 2011)

You can pick up a Tohatsu kicker for 2K, they use about a quart an hour trolling and just keep on running. I love mine


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## Far Beyond Driven (Jan 23, 2006)

Plenty of engines on charter boats going to 5k, 7k hours without issues, 90%+ spent trolling.


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## bad dog (Mar 31, 2004)

I have a 2011 Merc 115 4S tiller. I occasionally use it to troll. I lock down the Merc and use the Terrova iPilot to steer. I think it comes down to the boat and the type of fishing you primarily do.


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## Fishndude (Feb 22, 2003)

I have a Merc 9.9 4-stroke kicker. I had the idle set at 75 rpm, and I can pretty much troll any speed needed to get bitten. I run from spot, to spot with my Merc 115 2-stroke main motor, but troll with my kicker. I bought my boat completely outfitted for a great price, used. I didn't want to deal with figuring out how to troll slowly with a big motor, so I shopped the market for boats with a main motor, and a kicker. I have never regretted that. Bonus - my kicker was mounted on a Panther power tilt. Also, if I am dumb, and am about to run out of gas, that kicker can push my boat about 7 mph, and will go many miles on a gallon of gas.


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## DFJISH (Mar 30, 2009)

Some of the information on this thread is really bothering me. I just bought a 16' Lund Angler (1998) with a 1998 50hp Mercury 4 stroke. If it will idle down so i can troll for walleyes with it I'll be a happy owner. But then I read on here that idle speed in gear is VERY bad for the engine. Last thing I want is to ruin my motor. Even the guy who sold me the rig mentioned that if I trolled very slow that I SHOULD take breaks and run it hard for 1 spell in order to...I forgot. Then I read on the forum that guys are trolling days on end with 4 stroke 90-115hp motors and having NO problems. Am I making a seriously bad decision to troll with my 50hp 4 stroke? If it won't troll slow enough I was going to put a Troll-a-matic plate on it and proceed to troll at idle speed. I sure hope I can get this cleared up. Thanks for any replies.


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## kroppe (May 7, 2000)

Idle speed is not bad for any engine. 

Trolling with a main motor can be done. It is done better with a kicker, but can be done with a main engine.

If you have power tilt/trim you can get a little lower minimum speed by tilting the engine up a bit. 

I troll for salmon with my 97 Honda 90hp carbureted 4 stroke. If I am pointed somewhat into the wind and waves I can troll at 2.2-2.8 mph all day. With the wind and waves, or with calm water, it tends to be too fast. I troll with the main engine when my gas kicker is having a bad hair day, or I forgot to fill the (separate) kicker fuel tank.


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