What size outboard are you running

[spoolin01]

I'd say go with 2-stroke and definitely more than 10HP. The Nissan/Tohatsu 15 and 18 are the same weight as the 9.9, I think around 80 lbs. Other makes should be about the same, as noted. I use an older Nissan 15 on my 10' Quicksilver airfloor and it's great - light enough for easy one-man deployment, plenty of thrust, and not too bad on smoke. It planes 2 divers or 3 fishermen, using a lower-pitched prop. Your 11' might even handle the 25 if it wasn't too heavy, and I've found my airfloor boat to be pretty squishy when loaded at all, so power helps a lot. With 4 people, I'd wonder if 15HP would be enough. One thing about motor weight - I found with mine that there wasn't enough tube aft of the transom to float the 115 lb 9.9 4-stroke that I first tried - it almost swamped us with 2 divers quartering into some chop, and the stern wave was always washing up over the intake unless you slowed down carefully. The lighter 15 rides noticeably higher. Boats differ in the amount of flotation behind the transom, so take a look at how your boat handles weight there.

I have older Nissan 8 and 15 HP motors, and the injected 40, and they've proved to be reliable starters and so far no mechanical problems except one carb pickup tube that fractured.

 

[Nemrod]

I do not think that a heavy15 horse four stroke will plane four divers. Our 14 footer (the Cancuro is rated for 50 horsepower) which has plenty of planning surface with a 25 would struggle and the Merc 25 is no wuss like the heavy four stroke junk.

N

 

[deepstops]

2-stroke motors have no match in the power to weight ratio. They also have about half the moving parts that 4-stroke has, are less expensive up front, and are far cheaper to rebuild. Their downsides are smoke (not a real issue once underway IMO) and fuel economy.

You could buy a lot of fuel just based on what you're saving on the up front purchase price.

 

[cmburch]

Two-stroke versus four-stroke outboard motors

My 15hp 2-stroke does not give off noticable smoke even when rinsing at the end of the day in a 5 gallon bucket. I have never really given it much thought on how much gas my 15hp uses. The 6 gal gas tank goes a long way. You may find that lifting a motor on and off everyday that a 4 stroke may not have what you need for a small inflatable.

 

[Mr.X]

I finally took the inflatable out of the box and it's sitting in the living room. The transom looks sturdy enough... but after a weekend of weeding my back is killing me. The Suzuki 15 hp (four stroke) / Tohatsu 9.8 are looking awfully good now.

Cheers,

X

 

[adurso]

I have Suzuki four strokes on my big boat and little one. Although two strokes have their benefits, I hated mixing oil on the little ones, and ensuring a full reservoir on the big.

The big advantage for me is he quiet running of the four strokes. And the Suzuki swings a bigger wheel in the larger sizes.

The 15 on my 14ft aluminum john boat with three adults and a bunch of crab pots and bait planes fine.

 

[Nemrod]

You do not generally mix oil in the gasoline with a two stroke engine, not for about 30 years now.

Modern two stroke engines, particularly the large direct injection engines like Optimax and Etec are as fuel efficient as any four stroke, actually more so and are lighter.

N

 

[spoolin01]

Looks like weedin' time is OVER! If you get a chance, maybe see if you can trial any motor you're considering. You can tune performance a bit with prop selection, but the lower the power the more you get to choose: (planing) thrust, or speed.

 

[promocop]

Love my Tohatsu on my 9.2 Avon. Graeat. Motor. Easy start

 

[adurso]

You do not generally mix oil in the gasoline with a two stroke engine, not for about 30 years now.

Modern two stroke engines, particularly the large direct injection engines like Optimax and Etec are as fuel efficient as any four stroke, actually more so and are lighter.

N

The smaller engines (as we are discussing) with a 3-6 gallon tank have an injection reservior?

I thought the large direct injection engines had a reservior they drew from?

Never heard anything bad about Optimax, Etec on the other hand had many corrosion issues. It seemed that a good one was really good; and a bad one was reallly bad....