2.5 or 3.5 hp tender outboard

[stevd]

I am looking for some advice on an outboard.

Currently I have an elderly 4hp Yamaha 2 stroke from the 80's which works well enough, it is a bit slow to start when cold and takes some effort to get from my boat down to the tender. It is quite heavy really (I think 22kg) so it is a bit difficult but manageable for occasional use.

Next season I am hoping to move to a mooring where I will be using my tender a lot more so I was wanting to save some weight and get a newer outboard for peace of mind with reliability.

I was thinking of getting a smaller 4 stroke such as the Suzuki 2.5 which weighs in at 13kg or the Mariner 3.5 which weighs in at 17kg.

I have a 2.7 air-deck tender and was wondering if a 2.5 would be powerful enough, given that I will be taking bags etc out to the boat with one other person on the tender too? I certainly like the idea of just 13kg, but would I be better off going for the 3.5 Mariner which is still a weight save of 5kg?

There isn't a huge difference in price so that doesn't really bother me.

What are peoples thoughts and experiences.

Many thanks

 

[LadyInBed]

You need to consider (I nearly said weigh up) what conditions will be in the majority of use. Carrying and lifting on / off will be up neat 100%. Fully loaded into a strong headwind might be 1 to 5%, so if you are changing to reduce weight then the light engine will serve and only struggle on a few occasions when you could maybe make two trips to split the load.

 

[jamie N]

Honda 2.3. Lightweight, air cooled, ultra reliable, and has been pushing my Folkboat variously up the Caley Canal, and across the Pentland Firth at 3.7kts on a calm day.

 

[Iain C]

When I upgraded my yacht I had to make a choice between letting the old one go with a Suzuki DF2.5 which I'd had from new, or a Tohatsu 3.5 2 stroke which was an unknown quantity. On the basis that it was lighter, more powerful and won't spill oil in the car I kept the Tohatsu and have not regretted it for a second.

If I were you I'd seriously think of trying to find a similar Mariner/Mercury/Tohatsu 3.5 2T. So much smaller, lighter, more compact. And obviously it's far simpler and easier to maintain.

From a power perspective the extra 1hp makes a world of difference. My "live at the club" tender for getting to my mooring is an Avon Rover R2.80 and my on board tender is a Wetline 2.60. In the right conditions with just me on board and my weight carefully placed they will both essentially plane. With the 2.5 they are nowhere near it. There's probably a 4 or 5 knot speed difference between the two and in tidal areas that makes the world of difference.

I guess the only downsides are mixing fuel...a bit of a non-issue with all these clever mixing bottles you can get now, and the environmental impact. TBH as I drive a 280 mile round trip to go sailing, and when I go sailing I'm using sails anyway, it's minimal in the grand scheme of things.

Of course you have to buy second hand, but I really do think that family of engines are superb little units.

 

[RupertW]

We went the electric route and bought a Torqueedo for our 3m heavy rib 4 years ago and it been brilliant even with 6 people and lots of luggage in a chop. But we don’t have to beat tides.

A completely clean engine that refuels from the ships batteries with about 5km range (twice that with battery available now) and breaks into 3 parts that can be held by one hand to put in dinghy is perfect. But you really pay for that perfection.

 

[Stemar]

Neither will get the boat on the plane, and most of the time, you'll be able to put-put around happily with the smaller one. I don't know about you, but I've no desire to be out in conditions where the extra power would matter. It's reasonable to expect an outboard to last 10+ years, & I reckon 5Kg lighter will be starting to matter then, even if it doesn't now.

 

[dancrane]

My mate rigged up a neat side-bracket on his one-and-a-half-tonne traditional keelboat, to hold a Mariner 2.5 two stroke.

I doubted it would do more than froth and make a racket, but it was ample power to give three or four knots, even while towing another similar yacht into a headwind.

So I doubt if the OP's small inflatable really requires a heavier engine, unless it will routinely encounter choppy conditions. The lightness of these smallest motors makes them incredibly appealing.

 

[stevd]

So it seems most would go for the lighter less powerful option. Thanks for everyone's input.

The tender is only 18 months old....in hindsight I would have gone with a smaller 2.4m tender to make that easier to lift on board too.

 

[jac]

If your mooring will be further away, what about a dedicated " at the club" tender and engine. Use the new, light one only for cruises and have a slightly larger dinghy and outboard for the longer trip to and from car to boat when the extra size and weight might be needed. That way, you will only be moving the engine when you're on shore and will have the extra power when the dinghy is heavily loaded and you can have something smaller and lighter when on a trip.


For your " at the club" tender, something old and tatty is probably very appropriate as it minimises it's attraction to thieves.

 

[RupertW]

So it seems most would go for the lighter less powerful option. Thanks for everyone's input.

The tender is only 18 months old....in hindsight I would have gone with a smaller 2.4m tender to make that easier to lift on board too.

Yes to that. When our secondhand heavy GRP 3m rib was more patch than rib after 8 years of our ownership we were delighted to swap it for a 2.5m aluminium one weighing almost nothing in comparison

 

[lw395]

Some of those air deck dinghies are very draggy with a small engine. The vee-hull and keel makes a lot of immersed transom at low speeds. You can reduce the effect by sitting well forwards, if the outboard shaft isn't too short. A tiller extension is a good thing to have.
The problem is, if the drag is too much, the small engine won't rev enough to get near its rated power, so you end up with 1HP not 2.5. This is why people find torqueedos are sometimes nearly as thrusty as a petrol motor.
That said, my 2HP will shove my small RIB along quite handily if we keep the transom out of the water as best we can.

If you can try before you buy, it might help.

There is a lot to be said for an old GRP tender to go to and from your own mooring.

 

[dancrane]

...what about a dedicated " at the club" tender and engine...something old and tatty as it minimises attraction to thieves.

I like this idea, very much. I'd even like to convert a hard tender, adding shallow keels to which wheels could be attached...

...and which would protect a fixed propeller, driven by a boxed-in lawnmower engine so the boat is ever-ready for action, as well as unique and not worth stealing. Nor would it be hard to introduce a discreet kill-switch so the uninitiated couldn't borrow it.

My ancient father's ancient lawnmower always starts first time, even after months outdoors, unused. I wonder if he'd miss it.

 

[mbroom]

I was thinking of getting a smaller 4 stroke such as the Suzuki 2.5 which weighs in at 13kg

Many thanks

Don’t!! I have one, and if I leave it for a few months the carb gums up and is almost impossible to start. I do drain it.... last time the ultrasonic carb cleaning cost half the purchase price of the engine. When I collected it from the workshop, there were several Suzuki 2.5s with exactly the same problem....

 

[dancrane]

There seem to be so many threads about the shortcomings of small four-stroke outboards, I hardly know where to look first...

...can anybody explain simply, if the four-stroke process is intrinsically temperamental or vulnerable on outboards, or whether the manufacturing is at fault, or if lots of users are insufficiently careful about observing the recommendations for storage and cleaning?

I'll be buying an outboard at some point, and while I'd prefer a well-preserved two-stroke, I'd like to believe there are dependable NEW engines available...God knows, they're not cheap. Considering how clever and reliable, most Japanese petrol engines are reputed to be, it seems odd that small four-strokes have found so many unhappy customers.

 

[oldmanofthehills]

Get a nice 2hp Yamaha (2nd hand or channel isles;=) ) unless you are going vast distances in heavy dinghy. My old 19ft Sandpiper on had a 5hp and it was a yacht that weighed well over half a ton.

I used to carry my 3.5 honda 4-stroke across the marshes to my mooring and after using it, lift it onto the boat. Well my arms were getting longer due to stretching and I was wobbling in the dinghy lifting it aboard. And then a light engine came my way. Still a pain to carry and lift but not an excercise in agony. I dont think any of the small 4 strokes as as light as the small 2 strokes as need extra complexity, whats more they must be stored always the right way up or oil falls out and they blow up. 4 strokes are of course more economical but we managed 1 mile trip round St Helens Island in bad weather in our inflatable (foolish I know) with said 2 stroke still had fuel to spare in the tank.

 

[Tam Lin]

Don’t!! I have one, and if I leave it for a few months the carb gums up and is almost impossible to start. I do drain it.... last time the ultrasonic carb cleaning cost half the purchase price of the engine. When I collected it from the workshop, there were several Suzuki 2.5s with exactly the same problem....

Seconded. Buy a different make, please!

 

[johnalison]

I replaced my 2.2 Suzuki 2-stroke with the 2.5 4-stroke. The old engine was fine until it packed up, but in almost all respects the new one is better. Although theoretically no more powerful, it actually gives a lot more poke and feels about 50% stronger. Although I only have a small Redstart, it would be perfectly adequate for general use for a larger dinghy as I have seldom used more than 1/3 throttle, and the greater ease of handling would make it my choice.

 

[RichardS]

Seconded. Buy a different make, please!

The 2.5 Suzuki is a brilliant and light little workhorse.

Mine is running on 4 or 5 year old petrol and, after 6 months of lay-up during winter, it always starts first pull without fail.

However, to achieve this state of outboard nirvana one must a) always drain the carb through the carb drain when leaving the motor for more than a couple of weeks (running it until it stops is not the same thing) and b) ideally fit a small 50p inline filter in the rubber pipe just before the carb.

Richard

 

[BelleSerene]

I was thinking of getting a smaller 4 stroke such as the Suzuki 2.5 which weighs in at 13kg or the Mariner 3.5 which weighs in at 17kg.

I have a 2.7 air-deck tender and was wondering if a 2.5 would be powerful enough, given that I will be taking bags etc out to the boat with one other person on the tender too? I certainly like the idea of just 13kg, but would I be better off going for the 3.5 Mariner which is still a weight save of 5kg?

We use that engine to power a slightly larger air deck Zodiac. It’s quite powerful enough, with multiple bags and people. You’re never going to get the dinghy on the plane with it, but you wouldn’t be asking if you wanted to, and you probably won’t with a 3.5hp either although it’ll go faster.

But as several threads have shown, and I have suffered, this particular engine is incredibly intolerant of stale fuel and water content. And when it won’t start is just when you need it to. I do not know whether the 3.5hp, with slightly less microscopic carb jets, is more dependable. I assume that other brands are, as you don’t keep hearing the same problem remotely as much; others will know.

The Honda 2.5 may be light but being air-cooled is incredibly noisy. That’s what I used before I left it on the 5m contour off Herm. Can barely hold a conversation across the tubes with it running full.

If I could go again I’d try 2-stroke. Lighter, more powerful, tolerant to being stored at different angles, and far less temperamental. I’d either buy in the Channel Islands (I have noticed the prices rising!), or more likely second hand on eBay and pay someone competent to strip and service it. As has been said, the fuel mixing is easy these days with these squeeze-and-measure oil cans.

 

[prv]

If I could go again I’d try 2-stroke. Lighter, more powerful, tolerant to being stored at different angles, and far less temperamental. I’d either buy in the Channel Islands (I have noticed the prices rising!), or more likely second hand on eBay and pay someone competent to strip and service it. As has been said, the fuel mixing is easy these days with these squeeze-and-measure oil cans.

When I was in Alderney a few weeks ago I saw the people in another yacht on the moorings struggling with a temperamental outboard. After a while there was a definite air of “bugger it, I give up” and the thing was propped in a corner of the cockpit and left.

Shortly afterwards, the Mainbrayce RIB came out and handed up a nice new Tohatsu 2-stroke, complete with accessories pack but without box

For what it’s worth, my solution to fuel mixing was to buy a load of new 100ml screw-top plastic bottles off eBay and decant the oil into them. Each time I fill the 5l plastic fuel can with petrol I tip in one bottle of oil, and that makes the 50:1 mix I consider best for my engine.

Pete