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Author Topic:   Can 100-HP 4-stroke Troll at 1-MPH on Montauk
Layla posted 04-25-2003 10:43 PM ET (US)   Profile for Layla   Send Email to Layla  
I have an 81 Montauk with a 90hp Johnson 2 stroke primary and a 7.5 hp Evinrude kicker for trolling. We trailer the boat to both ocean and CA freshwater lakes. CA is already outlawing 2 strokes on some lakes. I am considering replacing both with a single 90 or 100hp 4-stroke. Do any 4 strokes of this size run slow enough to troll at 1 mph?
JBCornwell posted 04-25-2003 11:58 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Hi, Layla.

I bought my Suzuki DF70 4 stroke on the recommendation of a Montauk owner who had a Merc 90 4 stroke (essentially the same engine as the Yamaha F90, previously F100).

He often flotillaed with friends who had the Suzuki and it's rebadged Evinrude twin. He said they were smoother, quieter and just as fast as his engine.

I have not regretted his advicce for a minute.

The Suzuki and its current twin, the Johnson, have become the engine of choice for Montauks, and with good cause.

You will certainly hear from other enthusiasts for this engine.

You might do a search for Montauk Repowering discussions.

Good luck.

Red sky at night. . .

dgp posted 04-26-2003 08:27 AM ET (US)     Profile for dgp  Send Email to dgp     
Don't rule out the Mercury 60EFI four stroke. It only weighs 248# while the Suzuki weighs 335#.
jimh posted 04-26-2003 09:31 AM ET (US)     Profile for jimh  Send Email to jimh     
[Changed TOPIC; was "Re-power with 4 stroke."]
Sal DiMercurio posted 04-26-2003 11:35 AM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Layla, no a 100 hp will not troll down to 1 mph without a trolling plate.
Unless you troll into the wind.
whalernut posted 04-26-2003 01:36 PM ET (US)     Profile for whalernut  Send Email to whalernut     
I have seen one of those yamaha 100 4-strokes on a boat, it ran great and and was pretty darn quiet!! I would imagine, a smaller 4-stroke would get you into that slow speed zone, maybee a Mercury 60h.p. 4-stroke, and they are much lighter and EFI, so that should help :) Jack.
captbone posted 04-26-2003 05:47 PM ET (US)     Profile for captbone  Send Email to captbone     
Its a pain but a 5 gallon bucket with a short lenghth of rope dragged behind the vessel will get most montauks into that speed range.
jimh posted 04-27-2003 10:03 AM ET (US)     Profile for jimh  Send Email to jimh     
I don't think there are any engines that can troll at 1-MPH. Let us look at the numbers:

A typical 100-HP engine will idle about 800-RPM, have a 2:1 gear ratio, and run with a 17-inch propeller. A MONTAUK is an easily driven hull so figure the slip at no more than 35% Put those numbers into the propeller calculator and you get a minimum speed of 4.5 MPH.

To get down to 1-MPH (with that propeller) you would need the engine to run at 177-RPM, which is highly impossible.

To change the propeller pitch to get 1-MPH at 800-RPM idle, you'd need to go to a propeller with only 4-inches of pitch. They don't make such a beast.

The only technique to get to 1-MPH with a reasonable idle speed is to increase the SLIP. Towing drogue or adding a trolling brake is one way to accomplish that.

Sal DiMercurio posted 04-27-2003 12:04 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
You may need a kicker engine to troll with.
Such as a 10 hp.
dgp posted 04-27-2003 07:06 PM ET (US)     Profile for dgp  Send Email to dgp     
I checked this today, my Montauk with Mercury 50Hp four stroke makes 1.7 MPH at idle speed (750 RPM) in-gear.
jstachowiak posted 04-28-2003 09:56 AM ET (US)     Profile for jstachowiak  Send Email to jstachowiak     
Running: 70HP Evinrude 4-Stroke with 17 pitch OMC SS prop at idle 750RPM speed is 3.4MPH.
elaelap posted 04-29-2003 08:58 PM ET (US)     Profile for elaelap  Send Email to elaelap     
My old Katama with a 50 hp "High Thrust" (like a Big Foot) 13" pitch putts along at 2-4 mph at 800 rpm idle in gear, depending on wind and sea...just perfect salmon trolling speeds. No smoke, and I literally can't hear the motor over the sound of the ocean...course I'm getting a little deef in my declining years.


captbone posted 04-30-2003 01:07 AM ET (US)     Profile for captbone  Send Email to captbone     
It is for calm waters only but try trolling backwards in idle. That should also get most vessels close to 1 mph.
Tom2697 posted 04-30-2003 10:43 AM ET (US)     Profile for Tom2697  Send Email to Tom2697     
There is an old trick that can be used.....It's called slow trolling or bump trolling....bump the engine into gear and then put it back in neutral to troll at whatever speed you want. It's a pain in the neck but it also produces a killer effect on your lures....When in neutral, the baits will slowly sink. As soon as you start moving, the baits shoot toward the surface.

Also, a bucket or a drift anchor tied to the stern will slow you down. If you have a water ski bridle that connects to both stern eyes, using this will keep the boat going straight.

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