How much more reliable are 4t Outboards than 2t

jac

jac

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I have a 2002 2.5hp Tohatsu that is starting to annoy me. Used fine for 2 years - then laid up for a while. An expensive overhaul last year, fully serviced about March - worked and started 1st pull. Now - brand new fuel - nice looking spark - fuel on the end of the spark plug - no starting. Will fit new spark plug and try that but the existing one has done maybe 10 minutes.

My pattern of use is probably not ideal - we use club launch to get to and from boat so the tender & OB only really get used on an annual cruise or on occasional weekend. The rest of the time it sits on the bracket on the stern. I service it about the time that the boat is out of the water so it sits in the garage over the winter with fuel drained and gets treated to new fuel and sparkplug & gear oil etc about Easter

I'm thinking of replacing it with something say 3.5-4hp but 4 stroke but if it's going to be as much of an issue to keep running as this one then may not be worth the bother. SO - are modern small 4t engines better able to cope with infrequent use and be reliable enough to trust? Any particular engines that people would recommend?
 
Was the carb emptied last time you used it? Believe me although 4T's may be a bit more sophisticated a good 2T will be lighter per HP, have fewer moving parts to go wrong etc, etc. I'd drain the carb to make sure that you've got rid of anything that might have collected, then every time you use it run the fuel out with the fuel tap off. The issue maybe around our superb unleaded these days that goes off in weeks, forms varnishes at the drop of a hat which block the jets and passages through the body. My Tohatsu 3.5 I wouldn't trade for the world. Just try and heft some of the equivalent 4 strokes...
 
Gladys said:
Believe me although 4T's may be a bit more sophisticated a good 2T will be lighter per HP
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Absolutely! My 2.2 Suzuki is about 9 or 10kg, I can carry it easily with one hand around the leg tube. The boat astern of us at Mixtow the other week had a 2.5hp Suzuki 4-stroke, which was at least twice the size, and had a lifting harness around it suggesting that they had to crane it onto the boat.

The prices of good 2006 2-strokes are rising rapidly, for good reason!

Pete
 
I would echo the comment re emptying the float chamber on a small four stroke.
i have a Honda bf2 which was a bar steward to start until I let it run the float chamber dry after use.
doing this and waiting say 30 secs for it to fill up agian when the tap is opened gives it the ability to start first or second pull.
As said many times the jets are so small a little bit of gum in the fuel can block them.
 
I wouldnt swap my Tohatsu 9.8 hp for any 4 stroke. I only bought the tohatsu this year to replace the previous one stolen in Spain last year. the last one was 10 years old and still going strong.
 
We had a 4hp Honda 4 stroke. Nightmare - wouldn't start - sent off to dealer who couldn't fix it - suggested £300 for a new carb! Bought a 3.5hp Tohatsu 2 stroke. So far - fantastic. Light, starts easily, powerful, simple. 2 strokes are simpler and better - if you can find one!
 
For the last two years have stopped it by turning the fuel tap off and letting it burn the fuel from the float chamber. I did get some clogging in the past but liberal application of carb cleaner seems to have fixed that and fuel is def coming through. I have an oily sheen on the water from the unburnt fuel/oil being discharged and the spark plug is wet so it's def getting that far.

That led me to think of spark plug. I didn't bring spark plug or speak tester home with me ( have ordered one - gotta love amazon prime) so will swap tomorrow andsee if that helps but can see and hear a spark when held near the o/b block so at a loss as to why it should not start.

Just annoys me lugging something unreliable around. If the 4t engine was more in the league of a boats diesel or a car engine in terms of reliable starting I think the weight penalty would be bearable, especially with a small crane.
 
prv said:
Absolutely! My 2.2 Suzuki is about 9 or 10kg, I can carry it easily with one hand around the leg tube. The boat astern of us at Mixtow the other week had a 2.5hp Suzuki 4-stroke, which was at least twice the size, and had a lifting harness around it suggesting that they had to crane it onto the boat.

The prices of good 2006 2-strokes are rising rapidly, for good reason!

Pete
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It must have been a very old Suzuki 2.5 4-stroke as our DF2.5 weighs 13kg so even SWMBO can lean out and hand it to me one-handed whilst I'm standing in the tender.

I prefer 4 strokes to 2 strokes but in either case would recommended draining down the carb and tank if leaving for more than a week or two although, in my experience, this is more important with a 2-stroke as gumming-up with oil residues from evaporating mixture is even more likely.

Richard
 
We had a Honda 2 bhp 4 stroke outboard about 16 years ago and found it to be very unpredictable re starting - we went 2 stroke . On the other hand I have a Honda mower and strimmer - both 4 stroke - which are 9 and 12 years old which have always behaved perfectly.
 
The other thing to do is to add fuel stabiliser to the mixture to prevent the gumming that blocks everything. I use it in both the 2 and the 4 stroke never had a problem starting.
 
Three years ago I bought myself a new four stroke 2.5 hp outboard for my tender as a retirement present. It has been nothing but trouble. Last week I was on my way back to the hard after launching Tam Lin when it just cut out. Luckily I had my marine engineer with me and he rowed back! Then he took the outboard away and gave it a going over. The next time we went out, it started then cut out, then started five minutes later. This is just typical of the way it works. My engineer said that this make is no good and I will always have problems with it. Well, I was already fed up with it and thinking of changing it so I had a look on eBay. There was a Mariner 2 stroke, excellent condition, hardly used. It was reasonably close to me so I put a bid in and won the auction. When I collected it, it looked just as described, almost new. I took it to my engineer and he gave it the once over and confirmed that it was hardly used. I am now looking forward to many years of trouble free tendering!
Good two strokes are out there, you just have to look for them, or in my case be lucky!

P.S.
Anyone want to buy a four stroke outboard, three years old, just serviced, excellent condition?
 
How much 'more' reliable? I think you mean how much 'less' reliable! Two strokes only have 3 moving parts, piston, conrod and crankshaft.
Echo the above praise of the Tohatsu 3.5 2stroke, and we can still buy them from Mainbrayce etc new and guaranteed.
 
My 1990 2.5 Tohatsu (Mercury) was given to me with a corroded head and rusted crank and mains.I replaced the head , ring and seals and soaked the bearings and crank in oil.They're a bit pitted but the thing keeps going,always starts on first pull and idles perfectly.It's a contact breaker model by the way.A simple as they get.
 
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Have a 35 year old Tohatsu 3.5. Been sunk three times, once for over an afternoon (yes, tied ok, but bracket broke, so bracket still attached, but not engine) - still going strong and starts second pull. Given simple routine maintenance these simple little two strokes will go on for ages. Run out carb on the last trip of the day, and appreciate the weight differance to a four stroke !
 
I have had 2-stroke outboards for 4 decades, currently have a Yamaha 4hp, Mariner 2hp for the tender and Mariner 5 for the mothership.

All supremely reliable - the 4 & 5 have taken me several times across the Channel in calms - and - importantly - light.

When I checked out similar hp 4 strokes for someone at the Boat Show, my first reaction was ' what joker has bolted this to the floor then ? ' - they were unbelievably heavy !
 
The engine you have shouldn't be giving you problems given that you're draining the float chamber after use and keeping a clean fuel system. Once diagnosed and fixed it should be more reliable than a 4t in general. Certainly shouldn't be less so. Probably worth getting it sorted.
 
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