Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

[stjernefodt]

Hello all,

I have a 12 ft Saturn SD365 with aluminum floor. Had it coupled with a Mercury Sea Pro 25 HP 2-Stroke engine that worked really well with it. Had this combo for 3 years, but I just sold the Merc and want to go for a 4-stroke engine (just upgraded my larger boat as well to a 4-S).

I don't mind the price or dealer availability, I've been looking at the following models, want to keep it to rope start and manual tilt:

Tohatsu 20 HP - I like what I've seen. Cons would be the short tiller handle and it's probably loudest at cruise and WOT along with the Merc, but they both also look like the most powerful.

Yamaha F20 - Long tiller handle, smooth, but, the performance is a big question mark. Anyone have experience with this one?

Honda BF20 - Best fuel economy and quietest, however from the vids and comments I've seen it looks like the less powerful of the four, and slowest out of the hole. Might be just my perception or a bad prop.

Mercury 20 - The shifter integrated into the throttle worries me. Will I be able to troll at idle speeds without it shifting to neutral?

Basically I want the most powerful motor out of these four. My Merc 25 HP could plane with 3 guys and loaded with gear, but not with 4. Now, I will try to keep this boat for 2 persons and fishing gear only.

Any suggestions are greatly appreciated. A couple of pics of my boat:

 

[Drowned Rat]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I have the Tohatsu 18hp on my 14 footer. Really like it. If I were buying again, I'd go for the 20hp. I've had a number of Yamaha motors in the past and they are always a strong product. Of the ones you list, the Yamaha would probably be my choice. I would have picked that for myself, but I still think for the money, Tohatsu is the best bargain.

 

[firstboatbuild]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

Id go up 5 horse and go with the Merc 25efi and get away from the carbs. Merc has the the tiller mount shift for years now and have not heard of any issues with it. Honda is good just parts are expensive compared to merc and yamaha.

 

[stjernefodt]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I have the Tohatsu 18hp on my 14 footer. Really like it. If I were buying again, I'd go for the 20hp. I've had a number of Yamaha motors in the past and they are always a strong product. Of the ones you list, the Yamaha would probably be my choice. I would have picked that for myself, but I still think for the money, Tohatsu is the best bargain.

I think I saw your Saturn boat a while ago... got a couple of questions:

What is the aprox weight of your boat with engine, gear & persons? When loaded does it plane easily?
Has your Tohatsu been serviced by the dealer in any way, any nitpicks you might have on it?

I already discounted 25 HP 4-Strokes because of the weight. Need to take the engine off for each trip.

 

[Sea Rider]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I have a 12"8 footer rib with a 18 HP 2 strokes, with 2 mate crew totaling 350 kilos for the rib/engine /spear fishing gear combo, planes in less that 5 seconds, a 20 HP should perform better. Tohatsu 20 HP 4 stroker should be the best weight/performer priced.

 

[jrs_diesel]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

One thing to keep in mind, the Mercury and Nissan outboards, 30 HP and under, are built by Tohatsu for the U.S. market.

 

[Drowned Rat]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

My boat is heavy because of all the stuff I carry with it. Engine is 115#. I've not weighed it, but I'm guessing my whole rig is about 800# fully outfitted. The 18 Tohatsu planes it very nicely with 2 adults and 2 children. No issues with the motor whatsoever. It starts right up (electric start) and runs all day, any speed. I have a dealer close by but I service the engine myself. I will say that the 115# engine is just barely manageable lifting on and off the boat by myself. Any heavier and I couldn't do it. In that regard, I would prefer a 2 stroke for this boat but I need the 4 stroke because of where I take it.

 

[likalar]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I have a current model Honda 20hp pull start on a Achilles RIB. I also have a 20hp Yamaha electric start on an aluminum 14'. I love both engines, but there are some minor differences: The Honda is lighter by several lbs (maybe 15-20 lbs.). It starts on the second pull after storage of 6 months. It's also the quieter and smoother of the 2 motors. The Yamaha is also a great engine, but vibrates a bit more, especially at 1/2 throttle. Nothing drastic, but it's noticeable. The automatic choke on the Yamaha has worked perfectly. I also love the electric start feature, easy shifting, robust steering adjustment, and easy to use throttle set screw. The Honda's throttle keeper is a bit tricky to set, and tends to lose the setting.
Do you do your own maintainance? The Yamaha wins, hands down! The Yamaha's oil filter and plugs are up high and very easy to access. The Honda has the filter and lower plug down low, where they are hard to reach. In fact, you'll have to remove several screws to remove the plastic engine covers to reach the filter. Kind of a pain...Both have been 100% reliable, strong, and each should last a very long time. As far as performance, I can't compare the 2, as the 2 boats are so different.
A while back I had a larger RIB Zodiac with a 120 hp 2 stroke Tohatsu. Totally dependable engine for the 12 years I owned it. The only glitch? When it came time to sell, most lookers balked at the brand of engine, as it is not so familiar. I never had a lick of trouble with it , though, and the purchase price, when new, was a bargain.
Larry

 

[stjernefodt]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

Thanks for your valuable info everyone. Looks like all motors should do a fine job, so I guess I'm back to where I started, still undecided.

likalar, I have a 4-stroke Yamaha myself, I do all its maintenance, no problems so far like you said. Still the Honda should be the smoothest.

Drowned rat, my Tohatsu dealer is 60 miles away, but It sounds as I wouldn't be seeing him much because of Tohatsu's reliability.

On a motor this size, would Electric Start be worth the added extra 20 lbs of the starter plus the 45 lb battery? Would I see a noticeable speed penalty?

 

[Sea Rider]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

The lighter the sib/engine combo with the most available interior space for crew, the better, rope start is perfect for that size sib, the battery do jump in heavy chop, will need to secure it properly inside sib.

Happy Boating

 

[stjernefodt]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

Sea Rider, yeah I'm a bit limited in interior space. I love this little boat, I've taken it 15 miles offshore in the Sea of Cortez, calm seas though.

These past days I've been eyeing some 12-13 ft RIBs on craigslist, that cost a bit more than a new 20 HP engine, all of a sudden I'm having second thoughts about wheter to get the engine or a used RIB.

 

[Sea Rider]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

A rib is the way to go specially ribbing on calm waters like Sea Of Cortez, check a good used one, planninng to count with a 20 HP engine, go for at least a 380 mt rib or bit larger. Engine will wot them nicely.

Happy Boating

 

[emoney]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

Pay close attention to how you transport the 4 stroke. It can't be laid on a specific side (I don't remember which), or at least my Nissan can't. Just thought I'd throw this out since it seems you'll be tearing it down each trip. Did you choose yet?

 

[stjernefodt]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I'm liking the Tohatsu but I'm hunting for a deal on 14' RIB as well.

On the Tohatsu, I'm wondering If I should choose the power tilt version. Would 114 lbs be a bit too much hassle to tilt up a few times per day? My earlier Merc weighed around 110 lbs or so it was a bit of a struggle to lift if it was choppy. Then again the Power Tilt option is another component (electrical at that) that could fail.

And you're right about transporting it. According to the Tohatsu manual, you can lay the engine on its side (tiller side up) for transport only, not storage. I've transported my Suzuki 4-stroke kicker on the bed of my truck for periods of about 12 hrs with no probs.

 

[likalar]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

The power tilt is the way to go if you like to adjust trim while underway, but not very necessary for beaching or normal boating activities.... A 115 lb. engine would be easy enough to tilt up, as it is not the entire engine weight that your are tilting. You said you have a 120 Yamaha. The Tohatsu should be similar, I would guess.

Larry

 

[Sea Rider]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

If you are planning updating to a 14" rib, the engine way to go would be a 30 HP, 20HP has it's limitations, will wot/cruise nicely with max 3 total mates, not real heavy though, + light gear, but no further. Keep it simple, no power tilt, with time, trial and error will learn to balance rib & passenger weight accordingly.

Happy Boating

 

[stjernefodt]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

Thanks again for the info. Yes, If I do buy a RIB it would already have to include a 40 HP or so engine included. I would then sell my current Saturn boat.
Right now still leaning towards the Tohatsu, without all bells and whistles, for now, at $2539 shipped seems like a great option. Gonna give it a few more weeks of deal hunting on eBay and Craigslist.

 

[riverandocean]

Re: Suggest me a 20 HP 4-Stroke for my 12 ft Inflatable

I used to have a Honda 20 hp on a 14' Bombard..... Great motor, easy to start.... recall it was 105 pounds.... I could lift and move it easily, but to be honest it was underpowered when fully loaded.

Now I run a Honda 30 with electric start on a 14' Zodiac and when I am on the water.... the extra power is great with a full load.... we like to go boat camping .... family of 4 with a weeks worth of gear and food.... fishing, shrimping, camping......

Honda's are very reliable from my experience, but a little pricey.

Certainly go with a 40 on a 14' RIB!

Have fun out there.