4-Stroke OB Trolling

[JimS123]

We troll more than we still fish. I have always used a 2-stroke Kicker, and once set up right we can troll for hours without a hiccup. Periodically I run up to WOT, and in the Fall I always use OMC Engine tuner. Regardless, plug fouling or carbon buildup has always been a non issue. My current Kicker is a 1984 Evinrude 9.9 with about 600 hours on it, 90% of which is trolling.

When I say "trolling" I mean running at 1.9 mph in a straight line with fishing lines dragging out the back of the boat.

We are contemplating trading up to a slightly larger fishing boat, which would be equipped with a Merc 60 HP 4-stroke. I DO plan to install an electric "trolling motor" on the bow, but I would prefer to not have to put a gas Kicker on the transom. No type of electric motor would meet my "trolling" requirements.

I have no personal experience with 4-stroke outboards. My question is....any issues with running that big 4 cylinder, 4-stroke Merc at idle for 3 or 4 hours at a time, once or twice a week?

 

[dingbat]

Run 150 to 350 Hp 4-strokes 8-10 hours a day, 6-7 days a week during peak Striper season. No problems.

 

[ajgraz]

My understanding is that being able to troll all day long without fouling is one of the big "plusses" of 4-stroke OB's compared with 2-stroke...excluding DFI 2-strokes, supposedly.

 

[ondarvr]

It will troll along all day long with no problems, it may not be at the speed you want though, it just depends on the exact boat and conditions, it may get down to 1.MPH, or it may not get below 2.MPH, I've seen it both ways.

​I have all three, main, electric and small gas, motors, it allows for the correct presentation for every species and in varying conditions

 

[JimS123]

The performance specs say dead idle @ 600 rpm, at a speed of 1.9 mph. That's perfect for all the trolling I do.

 

[ondarvr]

They can't know what the idle speed will be, it's totally dependent on factors other than just the idle RPMs, it's determined by prop, boat size, weight, hull design, hull material, etc.

​Although some outboard manufactures do actual testing on different boats to let people know what performance to expect, they typically list this on a website though so it can be updated as needed.

 

[Silvertip]

Making oil (oil dillution eith unburned fuel) can be an issue with four strokes. Incorrect prop and running too cool can affect this as well.

 

[dingbat]

The performance specs say dead idle @ 600 rpm, at a speed of 1.9 mph. That's perfect for all the trolling I do.

I troll a ton of hours in the 2.0 to 2.5 Kt.range.

Feed them fresh fuel and keep a good water pump on it. They will perform all day for you. When done for the day, give them a good hard on the way back to the barn.

 

[JimS123]

They can't know what the idle speed will be, it's totally dependent on factors other than just the idle RPMs, it's determined by prop, boat size, weight, hull design, hull material, etc.

.

The test results were for the specific boat as configured.

 

[ondarvr]

The test results were for the specific boat as configured.

That's why my next sentence talked about actual on the water testing, I thought you were referring to what was printed in the manual for the motor.

 

[fishin98]

You should have no trouble trolling with that 60 Merc, with the right Prop pitch, you could get it .75mph. A few years ago fished (trolled) out of a 16ft boat with a 40Hp 4 stroke Merc with out issue 6-8 hrs a day for a week.