2 stroke or 4 stroke for 14' inflatable

[BC STS]

I recently purchased a 14' aquamarine inflatable boat it weighs 200 lbs and is rated for 30hp. The dealer I bought it from says he put a 50hp on his ( to give an idea of what it can supposedly handle). I'm looking at the Honda 20hp 4 stoke (101lbs) and the Yamaha 25hp 2 stroke (104.5lbs). At first I was only considering the Honda until I called a dealer who used to carry Hondas and now carries only Yamaha. He told me the Honda 20 is a weak engine and lacks torque. Eventhough he is a Yammie dealer I thought what he told me could be true considering the Honda is much lighter and smaller than other 4 strokes of the same hp. I plan on using my boat in various fisheries from the chuck (near river mouths not way out), lakes (will get a minn kota 50lb thrust motor mount for trolling) and the Fraser river (which has strong current on the upper reaches). I was told I need at least a 15 for the upper fraser but am thinking a 20 or 25 should be about right considering the two I'm looking at weigh considerable less than other brands with the same and higher hp rating. I think the increase in weight to go to a 30 or 40 would hinder the portability aspect as I like to deflate my boat after use and throw it in the back of the truck along with the motor and trailer I will be buying (possibly seitech dolly or Davis transom wheels. opinions?) I will normally be travelling with with 2-3 persons (including myself). Any opinions on the two motors listed above or suggestions of others will be greatly appreciated as this is the first boat I have owned and would like to make the right purchase the first time around.

 

[fishdog4449]

Re: 2 stroke or 4 stroke for 14' inflatable

I would get the 2 stroke. They have much more torque, hole shot, top end power, and they are MUCH lighter. The only advantage a 4 stroke has is better fuel effeciency. But in the horsepower range you're talking, you won't get guzzling gas even with a 2 stroke.
I used to have a 25 Evinrude 2 stroke that i could carry around with one hand, so if you're going to be carrying the motor, I'd go with a 2.

 

[JB]

Re: 2 stroke or 4 stroke for 14' inflatable

First of all, I would never trust a dealer who brags of overpowering any boat or bashes an engine he doesn't (any longer) sell.

The Honda 20/25/30 is a superb engine, and as light or lighter than similar 2 strokes. Smoother, quieter, more economical and cleaner.

These myths about 2 stroke HP being bigger than 4 stroke HP, lighter, hole shot, top end, etc. are just that, myths.

The Honda would be my choice, hands down.

 

[QC]

Re: 2 stroke or 4 stroke for 14' inflatable

I'm with JB on the myth stuff, but I'd go with more horsepower.

 

[wbeaton]

Re: 2 stroke or 4 stroke for 14' inflatable

At 100 lbs I doubt you will be carrying either motor around. Even my 1987 20 hp is a handful at +80 lbs.

I run 12' inflatables with 9.9-15 hp 2 stroke motors in rivers during periods of high flow (I've got a great job!). With me and a partner plus our gear the motor does fine. Our boats are a lot lighter than yours. I would think either motor would work for you. However, I might take the 25 hp only because of the extra push. I don't know the section of river you'll be on, but three adults and their gear in a 200 lbs boat in fast water might need a little more push. Of course, you could step the prop down a pitch and get the same result. So I guess I have no opinion afterall. Might as well get the Honda with a low pitch prop.

 

[BC STS]

Re: 2 stroke or 4 stroke for 14' inflatable

Thanks for the responses thus far.

wbeaton what is a low pitch prop and how do you step a prop down a pitch? When you said I might need a little more push were you saying you think the 25 would be inssuficient or the 20. Thanks.

 

[wbeaton]

Re: 2 stroke or 4 stroke for 14' inflatable

The 20 hp might be a little lacking. If you were running on a lake I'd say no problem, but you said you would also be on the small end of the Fraser. If I took my motor there I'd want to know it was up to the task. The best thing to do is to test it out. Could be that the 20 hp provides enough power to push you, your passengers and gear in all river conditions. The normal recommendation is to select a motor no less than 75% of the max rating of the boat. In your case the 20 hp is only 67% where as the 25 hp is 83%.


I am no prop expert and I'm sure someone will come along and dispute this, but here is my opinion...

The motor will come with a standard prop. Generally, they are chosen for best all around performance. They are measured by diameter and pitch. Stepping down a pitch in the prop will give you a little more bite in the water, give you a better hole shot and give you a little more responsive handling. It might drop your top speed a little, but I doubt it will have much effect that way. It could even add to your top speed if it increases the engines RPM's. Of course, you have to be careful not to go too low in pitch because you don't want to over rev the engine either. Stepping up in pitch should get you more top speed, but it will make planing more difficult. Planing an inflatable boat can be hard enough. That's why I might go down a pitch from the standard prop. I think it would ensure you get on plane and give you a little more control in fast water. Presumably the 25 hp wouldn't need to change the prop since it has the extra ponies. However, it is noisier, dirtier and will use more fuel.

Either way, ask your dealer which prop would be best. They are supposed to be the professionals.

 

[Snowdrggn]

Re: 2 stroke or 4 stroke for 14' inflatable

BC STS,
I hail from where the Nechako meets the Fraser. I ran a 15hp evinrude on a Zodiac 310 (74lb boat, 72 lb motor). With two people and carefully propped it did well. I sold the Zodiac, and bought a Zebec SE320, a few inches longer, a lot wider, and 135 lbs. The 15hp wasn't quite enough in faster water. I came across a sweetheart Yamaha, and love it, although @104lbs, it is a chore dragging it around. I would go with the 25hp Yamaha as it is only a bit more $ than the 20 and the same weight!

Cheers,
Snow.

 

[Expidia]

Re: 2 stroke or 4 stroke for 14' inflatable

I traded a 2006 30 Merc 4 stroke EFI for a 2007 40 Merc. my plates max hp.

Big difference in the weight from a 2006 to 2007. The 30 weighed in somewhere around 239 lbs (a monster) The 40 is only about 215. So beware of model changes year to year as the dealers want to dump hard to move models on you.

I still have a 2005 9.9 Merc 4 stroke long shaft that weighs about 85 lbs and it sounds light, but you still can't carry it around very easily.

Just my personal taste, but I would never buy another carburated outboard again. The EFI stands for electronic fuel injection. You would never buy a new car with carburetors! EFI starts like a dream . . . everytime, for me!

I personally would never buy a 2 stroke either. You will be trading up to a bigger boat at some point (we always do) so I think EFI and a 4 stroke will hold the resale value better.

If your boat has a max 30 plate. Get as close to the 30 as you can. For 5 or 10 less hp you will never be happy as you will always be saying to yourself "I wish I got the max" (I did).

I would do as the other poster said: try each motor in various hp ranges out on your boat, even if you have to go to a boat rental dealer (this is what I did).

I also agree that the dealer you spoke with is a jerk.

Also many brands (especially some smaller hp models) are not made by the name brand you are paying for. That 30 Merc I first bought I found out after I bought it was made by Nissan, but I was paying up for the Merc name and resale potential.
That same year Yammie made the heads for the larger Merc models too.

All of the above advice is exactly what I've been through over the past year.

 

[Snowdrggn]

Re: 2 stroke or 4 stroke for 14' inflatable

From 1988 to present the Yamaha 20hp & 25hp are the same weight. The 30hp is heavier, as it is a three cylinder, as opposed to a twin.

cheers,
Snow.

 

[TOHATSU GURU]

Re: 2 stroke or 4 stroke for 14' inflatable

The Yamaha is by far the better choice. It has a faster hole shot which means you can go with a higher pitch for more top end speed. The Honda is cleaner, not as loud and has better fuel economy at low speeds....None of which are important to the average person who is running an inflatable. One thing though, torque is a useless term when describing an outboard. Torque is a measurement off the engine powerhead and is only one factor used in determining prop shaft hp. Hence the only valid way to compare(output) one engine with another is hp at WOT.

 

[Snowdrggn]

Re: 2 stroke or 4 stroke for 14' inflatable

BC STS,
Check your PM..........


Cheers,
Snow.

 

[Snowdrggn]

Re: 2 stroke or 4 stroke for 14' inflatable

BC STS,
I would go with the with the highest power to weight ratio. Divide the horsepower by the weight, higher result is better. Also bear in mind the WOT range of the engine (higher is better). Other than a brand new Honda 20 (101lbs), you will prolly end up looking at a 25 yamaha ('88 or later, 2 stroke), '71-82 OMC 25 (88lbs, without thru hub exhaust), or possibly a 2 stroke Tohatsu/Nissan.

I use the 25 Yamaha, it has proven 100% reliable, easy to start, and performs well. Then off to the water you go with a selection of props, gps and an inductive tach, to do some tweaking. Prop selection an motor height is critical on inflatables as ventilation and spray are very real issues, as well as motor trim angle. A couple of hours fiddling/testing is well worth th effort!
I'm able to run stably at 36mph (GPS), and have a hole shot that makes the unaware require clean underwear.


Cheers,
Snow.

 

[deejaycee_2000]

Re: 2 stroke or 4 stroke for 14' inflatable

When it comes to inflatables, yamaha is no.1 on them, proven by me for the last 26 years ...... PS. I have a 8,5" inflatable with a 30hp modified motor on that pushes out about 55hp ..... so nothing is impossible ......

 

[whywhyzed]

Re: 2 stroke or 4 stroke for 14' inflatable

put a 30 Yamaha on mine... I would say 25hp would do it. 30hp is about right I feel. If I throttle back to about 3/4 or 7/8 throttle, the boat does a nice cruise at about 23mph, the hull rides nice at that speed and the motor is quiet. I think a 20 would be wound out to the nuts vibrating and buzzing to do the same. I have a 20 Evinrude- I should try it.
I was sold the boat under the false pretense that it was rated for a 40HP, but it's not, it's rated 30 as is yours. I would be really careful with a 40- adult drivers only.. but I might have tried it if I had come across a great deal on a 40. I also put several patches on mine where seams were leaking so the jury is still out on quality of this thing. The paint is chipping off the seats where the crappy seats flex too... I'm thinking of a console and forward facing seat next year if it holds together. I also added 100 rivets to the side gussets of the floor panels before assembling:

 

[BC STS]

Re: 2 stroke or 4 stroke for 14' inflatable

I agree the seats are really cheap, broke one of mine the first time out but got a replacement. Dealer says he is aware of the problem and has notified the manufacture but no imporved seats as of yet. What length is your boat? The 14' er I bought didn't come with loops on the front like yours has even though it was advertised as having them. The dealer said they don't put them on the 14'ers I too thought it was shady how the boat is rated for 40 on ebay but only 30 on the transom, but I got a good deal on it so I bought it anyway. How much does a your Yamaha 30 weigh do you think it is portable for to people to put on/off every outing? Guess I'll have to find a used one if I opt for the 30. THanks for all the advice everyone

 

[deejaycee_2000]

Re: 2 stroke or 4 stroke for 14' inflatable

very nice yamaha ...... a 30 yamaha can be put on by yourself very easily, I do it all the time .... come on guys everyone knows the seat are just to keep the boat together not for sitting on, when riding a inflatable you must sit on the floor, unless it has a centre console ......

 

[whywhyzed]

Re: 2 stroke or 4 stroke for 14' inflatable

haha... yeah I'd be sitting on the floor if I put your engine on djc!

The 30 is manageable for me - 130 pounds-ish....I'm a bigger guy but can mount it alone.
Look for a good used well maintained motor - got mine locally for $1000. Believe it or not it's a 1987 - looks like a 2005..(the guy waxed it annually even!). I was not concerned about age at all, just check compression, lower unit oil, look for grease on all the linkages etc. and see how it runs. Very hard to find new short shaft motors (here in Ontario anyways)- most are long shaft.

mine is 4.3m/14'...good it has those handles... I used them to tether on the registration numbers. (I print and laminate and tether) -check the rivets real close on the aluminum floor- rivet heads were all falling off mine - if the heads fall off they will be rolling around under the floor and could puncture the boat- I drilled all the rivets out and replaced them and added many more (used a whole box of 100). I agree the price was great, (less than half of competitive boat). we'll see how it lasts.

 

[ron7000]

Re: 2 stroke or 4 stroke for 14' inflatable

what a bunch of pussies,

10' w/ 2006 25hp yamaha, 40mph if the chop and tide are in my favor.
the 25 is 106 lbs, it is portable but not a fun portable. I wouldn't get anything less than a 50hp.
you're a loser if you buy a 4-stroke.

 

[deejaycee_2000]

Re: 2 stroke or 4 stroke for 14' inflatable

well said ron, but that 25hp on your inflatable is still childsplay ... I have full modified 50hp pushing out 70hp for that inflatable of yours ......