Picking a motor for a KL Industries Pro 120 boat

[DaveInGA]

I've finally settled on getting a KL Industries Pro 120 as my small lake/pond boat and get a larger boat later for the big lakes here in GA.  I'd like to get a motor for it, but am having a hard time making a decision.  

It apparently will get up and plane with either a 9.9 or 15 horsepower two cycle, so I'm looking at those.  

But I'm interested in the fuel efficiency and quietness of the four cycles.  KL recommends no larger than an 8 HP ina four cycle.   Does anyone know if an 8 HP four cycle will bring a boat up on plane the same as a 9.9 HP or 15 HP two cycle?

Or better yet, why would a company recommend so much smaller an engine in a four cycle?  What are the performance differences in the two engine types?

Thanks in advance,

Dave

[Skwerl]

The difference is weight- four cycles are typically much heavier than the same power two cycle. More moving parts, more maintenance, more repairs, messy oil changes, etc. The ONLY reason four cycle outboards are on the market is the governmental EPA laws. The newer two cycles are very clean, quiet and a 10-15 horse motor isn't going to use enough fuel for it to make a difference anyway.

I go to a fly-in fish camp in Canada every year. The guy has camps on 15 lakes and each camp has 4-6 boats/ motors for client's use. Every one has a Yamaha two cycle on it. He uses 6, 8 or 9.9 horse depending on the size of the lake. Even with the 9.9, it's almost impossible to burn a 5 gallon tank in a day. Those lil Yamahas are bulletproof.

[DaveInGA]

What are the better two cycle engines these days?  Have some of the smaller motors improved in technology?  I'm thinking 9.9 HP is plenty of motor and am not sure about buying new vs. used.

[Fish Chris]

I see you like the two strokers...... and yes, they are lighter.... course I'm not acustomed to picking mine up and carrying it around on my back :-)

Seriously though, I found my old Honda 9.9 four stroker to be VERY low maintenance. It held exactly 1 qt of oil, and I (cleanly) changed it about 2 or 3 times a year, in about 15 minutes....... which more than offset having to screw around with two stroke oil mixing, every time I filled my tank.

Now, when you talked about how clean, quiet, and economical the newest technology two strokers are, your right........ but only in the larger models. To give you an example, the new Evinrude E-tech, is only available "as small as" a 35hp, and even so, its specs, like weight, fuel economy, etc, are not near so impressive as the 150 hp's, and up (read; not much, if any better than small four strokers)

My brand new Yamaha 25hp four stroker will burn about 3 to 4 gallons of gas in an all day fishing trip. I would be willing to bet that a 2 stroker would burn at least 6. Okay.... that's only 2 or 3 gallons a day savings, but multiply this X's my 140 days a year on the water, and your looking at about 350 gallons.... or about $1000 a year ! That's a good chunk of change for me.

And finally, in my case, there are at least a couple of Nor Cal trophy bass lakes which only allow 4 stroke motors, "no matter how new, or how clean", and I totally expect to see more lakes like this in the future.

Loved my old Honda, and loving my new Yamaha even more ! :-)

Peace,

Fish

[DaveInGA]

So if you're buying a four stroker vs. a two stroke, will the equivalent horsepower rating provide basically the same oomph driving the boat?  I want to understand why KL Industries advises buying no more than an 8 HP four stroke while they recommend a 9.9 or 15HP two stroke.  What am I missing here?

I did notice the 8HP four stroke weight about the same as the 9.9 four stroke.

[RatONaStick]

Dave

15hp is 15hp. The problem is that the four stroke engines are heavier than a two stroke of the same hp rating.

Basically you don't want an engine that weighs anymore than about 75lb, which is what the 9.9hp and 15hp 2 stroke Johnson/Evinrude weighs. I doubt you will find a 15hp 4 stroke that weighs close to that.

I'm running a 1989 15hp Johnson on my KL 120. With the stock prop (9.5"x10p) I was having trouble planing with a full load in all conditions. Plus, I was way under the recommended operating range of the engine. I ended up having to swap to a lower 10"x7p prop to get up on plane and into the correct operating range.

I use about a 1/4 tank of fuel (6 gal tank) an outing on a 1300+ acre lake. I consistently do 13 to 14mph, and i can get 15-16mph out of it on a good day. any faster and the bow starts plowing.

I strongly advise you to go with a 15hp 2 stroke. It sucks getting out on the water only to find out the boat won't get on plane and you can't go anywhere.

[DaveInGA]

Brandon,

Thanks for that information.  That's what I was looking for.  I think I'll try to pick up a used 15HP and swap out to the prop you suggest.  The only four stroke with a reasonable level of weight I've seen was the Nissan/Tohatsu at around 80 pounds.  I think I'll be better off with a 60 pound 15HP two stroke.

Regards,

Dave

[RatONaStick]

Dave

I don't know where I got that 75lb figure from, 60lb is probably more like it.

Basically what I should have said, you want the lightest 15hp outboard you can get.

When you do get a motor, test it out with the stock prop with a full load before making a prop change. You don't want to over rev the engine, plus depending on your load and condition of your engine, it migh be fine.

[abelfisher]

Before I bought my new bass boat, that is the exact boat I owned.  I had a 4HP/4stroke Nissan on it.  If you read more into the boat, it is the weight that is the issue.  It is a very decent boat.  very stable for the size (tri hull).  I also had a 43 # Tm on the bow.  Great little boat.

[DaveInGA]

You guys are definately making me feel good about my choice of boat.  I feel like, after all the research I've done, it'll be perfect for my applicaiton, which is small ponds to medium sized lakes with motor restrictions.  

Ok, now that it's obvious I need a two stroke for the weight savings, what are the lighter and more durable, dependable two stroke brands rated at 15HP and is there a good place on the internet to buy a "program" motor or some such?

Thank you for helping me with my selections.

Regards,

Dave

[Travlin_Man]

www.smalloutboards.com

[DaveInGA]

That's a pretty good link.  Are there others and what are the "contenders" in the 15 HP two cycle motor brands?

thanks for the link,

Dave