4hp 4 stroke outboard - recommendations?

I moved from a tohatsu 9.9 2s to yamaha 6hp 4s this year.
Spent an extra 100 on a high thrust prop.
Pros: great econ,great power from the prop, no more mixing fuel and oil.
Cons: Heavy Heavy Heavy !!! An extra 20 odd kg as i remember.
Yamahas are the way to go thou , great engines.
 
I had the same problem last year...settled on a Mariner 4 and have not regretted it. Engine sat for 8 months and started first pull! Very economical, quiet and portable.

Servicing looks simple enough. Sailing Today (sorry PBO) did a great step-by-step article on renewing the impeller on this model. It was a tricky enough job but dooable on a DIY basis. My local dealer was looking list at £675 but I got it for £625 - this dealer is a tight-fisted $%*&^ so I would expect this type of discount from dealers in general.

Collecting the engine in person saves on high delivery costs so it may be better to source from someone near you - especially true for smaller engines where delivery costs can eliminate any savings made.

I have since learnt that a lot of the smaller outboards are made by the same company but rebadged under different names. If this is the case and, for example. a Tohatsu 4 was basically the same as the Mariner 4 then I would now go for the cheaper Tohatsu.

Incidently, if anyone knows which engines are rebadged models under different trade names I, and others, would surely like to know...
 
Re: Whats with the 4 stroke thing?

I agree with you in all these negatives but the factors that swung me in favour of the 4 stroke were a) no premixing hassle so I could use the fuel from the main tank or other fuel provider directly and b)lower pollution levels - both from noise and fumes.

I don't know if this is misplaced optimism but I feel more confident in the reliability of the four stroke engine, I've also had negative experiences from fouled plugs on 2 strokes from letting the engine run at tick over for long periods but I think it is just personal preferences coming into play at the end of the day...now, if somone came up with a small, competitively priced diesel I would be even happier.
 
The PBO report was in the May issue. 6 four strokes and 5 two strokes, all 9.9 hp, were tested. Maximum speed, fuel consumption and thrust were all tested. The cost of replacement impellers, anodes and propellers were compared as were price, weight, capacity, alternator output, whether they had electric start and warranty period. The usual comments about ease of handling and operation were made. Unfortunately such testing does not, and cannot, cover long term reliability.

The "Best performing two stroke" was the Mariner 10ML while the "Best on test" was the Tohatsu M9.8B, also a two stoke.
 
Re: Whats with the 4 stroke thing?

I have a very simple view of these things. The simpler the engine the better. The modern 2-stroke is a far better engine than it's historical ancestor. Better oils, electronic ignition and Jap engineering have combined to make 2 strokes very reliable. I will stay 2-stroke until I have to do otherwise. The small 4 strokes are an abortion, any marine engine that is fussy which way up you stow it is going to be got wrong.... Every time I hear Honda BF2.3 I hear a Seagull
 
I would go back to 2-stroke. Bought a Honda BF2 about two years ago, it has done in total maybe 2 hours work and kept in bow locker the correct side up.
I used it last week and it seized solid.Under investigation found the oil had drained into locker......it seized within about a minute. ps. is there any way to un-seize it. A friend reckons piston/rod and crank are all one unit and it would be cheaper to buy a new engine.

Go 2 stroke or check the oil every time.
 
I got a Honda 5HP 4stroke with my boat. It's 5 years old but had done very few hours. It starts fine, but it tends to die when ticking over and cannot be relied on to keep running when I start it as a precaution (I like to sail on and off the mooring). Even after an hour's run it will die (or not) when you return to a no-load tickover situation.
I've tried adjusting the tickover and mixture to the specs in the workshop manual and tried a new plug. I've checked for airleaks on the manifold, all the usual stuff, but it just isn't reliable enough to depend on.

So my vote would be for some other make. A multi-agency fitter I spoke to suggested the Mariner is a far better motor.
 
I DID go back to 2 strokes. I had 2 Yamaha 4 stroke 4 hp and sold them both last year and went back to the Mercury 3.3 2 strokes. Reasons? Weight, having to be VERY careful laying them down or storing them in lockers - one hydraulicked on me (oil ran back through the head into the inlet and into the bore) O.K. fixed in about 15 minutes but not what I want when I am trying to get ashore for a beer. Anodes were pricey and they were both difficult to start at times. Best move I made was changing back to 2 strokes. Fuel is kept in 2 X 5 liter jerry cans - when one is empty I slosh in 50~100 ml of oil and 5 liters of petrol then give it a good mix (100:1~50:1) Engine starts first time and is comparatively light weight - only down side is loss of reverse gear but that is not a problem.
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"Artificial intelligence is no match for natural stupidity"
 
I agree with all above! Small 4 strokes are a pain and long term a waste of money.
9.9hp and above they are a bit better if you go for the Honda, Who have been doing 4 strokes for a very long time and have sorted out most of the teething probs.
Most of the others have long term faults and especially if they are not serviced like a car regular.
The little Mariner/Yamaha 4/5hp 2 stroke is the most robust, Great little engine EVER made and i would recommend one of these.
Looked after it will last for years and will withstand the most terrible abuse.
I have run them on hire fleet dayboats, Day in and day out for years. I have also tried the Hondas and a number of other small make 4 strokes and they all fell apart in an alarmingly short time.
The only real reason for the push in 4 strokes is because of the European directive on emissions, which is trying to faze out 2 strokes.
I will be keeping mine till the bitter end!!

Joe
 
My Parker 21 has a 5hp outboard in the well as auxiliary. When I bought it it had a Mariner 2-stroke which the previous owner found was unreliable on tickover for long periods (he kept it in a marina and needed to mill about waiting for things). So he bought a Mercury 4-stroke which he passed on to me in it's original box, unused.

So I was able to do direct comparisons. The 2-stroke does indeed oil up and stop just when the other guy has made up his mind what to do and you need to buzz about without delay. The 4-stroke will tick over all day and guns up fine when asked. For cruising at mid-throttle the 2-stroke wins by a mile for noise and vibration - Something to do with having twice as many bangs per rev I suppose.

And the 4-stroke uses almost exactly half the amount of petrol (1 litre) per mile/hour/whatever. And no messing with oil either. So I've stuck with the 4-stroke.

Geoff
 
Re: I, and quite a few outboard mechanics

that I know are with you all the way. I've had a few 2 strokes over the years. Mariners and Tohatsu in the 2.5 to 9.9hp range in the main. Not only is trouble with these engines extremely rare but it's easy to fix if it arrives.

Because I forgot all about my 5hp Tohatsu for the best part of a year. It sat on the garage floor on it's back with half a tank of fuel in it. I put it in the tank, two pulls and away it went. I've just got around to servicing it. Took about 40 mins. This 4/5hp model, you buy the 4 and turn it into a 5 by taking a strangling plate out of it, is up there with the Briggs and Stratton lawn mower engine in the reliability stakes. And there's no higher praise than that.

You do see a lot of blokes with Honda's rowing.
 
our Suzuki 4 hp 4 stroke seems good.

We changed our Yamaha 5 hp fora Suzuki 4 hp 4 stroke for no other reason than the unpleasant noise of the 2 stroke.

With the engine in a cockpit well the noise is right next to you .

The engine is 2 or 3 years old and pushes our 22 footer better than the old 5 hp. Much pleasanter on the ear. Cant really comment on reliability as we have only owned it for one season.Allways starts easillly and frugal on fuel. /forums/images/graemlins/cool.gif
 
Re: I, and quite a few outboard mechanics

If you remove the strangle plate it will improve the power but you should also change the needle valve and jet to the larger engine type to get the full benefit.
Also by running without the bigger jets you will be running it on a weak mixture which could cause the engine to overheat and sieze up.
Joe
 
I have a 1979(!) Yamaha 2B and <u>never</u> had any problem. Very light (9.8 Kg), absolutely reliable. Only change spark plug and inspect/renew impeller.
Just before setting sails for a 2-week holiday this year I discovered (while checking the impeller) that the impeller housing was broken. As the part had a 10-day delivery time, I assembled back the engine and sailed. Never needed a second try to start it.
I was dissapointed to hear that Yamaha is not marketing 2-stroke outboards less than 5HP any more, as I was planning to go for a 3-4 HP (the 2B producing actually 1.5HP)

Bottom line: Unless absolutely necessary, don't go for 4 strokes.
 
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