2 stroke outboards

[ip485]

Wanting a really reliable outboard and having had more than a few problems with a new four stroke suffering a sticking carb. if fuel is left in it for any more than a few days I am wondering whether two strokes are more reliable?

I am assuming purchased second hand a 2 stroke is still legal for non commercial use?

I am also guessing like for like they are lighter than the equivalent 4 stroke?

Thoughts please.

9.9 hp is the engine in mind and weight is reasonably critical with the dink on davits although a 9.9hp just comes in under the all up max weight.

 

[PabloPicasso]

Personally I love 2strokes ever since I had an rd350 Yamaha as a teenager. But yes, lightweight, powerful, a bit noisier and smellier. I think the ban is non sensical greenness myself. But there you go.

 

[Seajet]

Secondhand 2 strokes are perfectly legal.

I have always had them and don't fancy the extra weight of a 4 stroke for one thing.

I have had a Yamaha 4, now have a Mariner 5 & Mariner 2, all perfectly reliable; the 4 & 5 have motored my boat across the Channel several times.

As long as it's reasonably maintained, a 2 stroke is a fine engine.

 

[ip485]

Do two strokes suffer from sticking carbs. which seem to plague four strokes with "modern" fuel?

 

[davidpbo]

Yes, Damage limitation can be effected by running the carb dry at the end of each period of use. I have still had gunge the consistency of builders squirty foam in the float bowl but may have missed running it dry on that occasion. I would imagine the same is true of 4 strokes.

 

[ProDave]

Do two strokes suffer from sticking carbs. which seem to plague four strokes with "modern" fuel?

Mine had a blocked idle jet recently, so I guess they are prone to the same fuel problems as any engine.

 

[TSB240]

Thoughts please.

9.9 hp is the engine in mind and weight is reasonably critical with the dink on davits although a 9.9hp just comes in under the all up max weight.

If you can find one go for a Tohatsu 9.8. They are the lightest 2 stroke twin of that power output. Geting to be a rare find now.

I beleive it is still posible to obtain new from CIs!

 

[rbmatthews]

Two-strokes are perfectly legal, even new, provided they meet emissions regulations. However, to achieve this, the manufacturers have had to develop direct fuel injection systems and pressurise the air going in and the like, but with all the extra gubbins required, it is generally only practicable on the larger engines, and consequently there is not so much a weight differential between 2- and 4-strokes any more, neither is there any difference in fuel consumption between them. Modern two-strokes are very efficient - we can get up to 3 NM/litre on our Mariner Optimax 75hp, for example. Unfortunately, the weight penalty of the DFI means that it is not practicable on smaller engines, hence most engines in this range being 4-stroke now. However, as one post said, two-stroke second-hand engines are still perfectly legal, regardless of emission levels.

I think the problems with deposits in the carb that you mention happen to both 2 and 4-strokes - see the heap of posts on this forum on carb problems with Tohatsu's and others, for example, which are invariably solved by cleaning out the carb and using completely fresh fuel. These problems are a fact of life with all the additives in modern fuel, unfortunately, regardless of whether it is 2 or 4 stroke. It is the price we pay for not poisoning the environment with lead and causing brain damage, like they did in the old days.

Rob.

 

[single]

First thing to do is strip the carb, good clean with carb/intake cleaner spray (or brake cleaner) , new filter and plug and hey presto.Then run the carb. dry after each use. I bet 95% of second hand ones have had very little use and just need a good service.If you think about it, there is very little to go wrong. Its just people don't look after them.Suppose you may as well change impellor and gear oil then engine should be like new.As for makes, i love Mariner/Mercury and Tohatsu.I really can't see why they were banned! Its not as though small outboards contribute that much to pollution.

 

[Seajet]

Never had sticking carbs on my Mariner 2 & 5; I religeously empty the tanks every winter - into the lawnmower, strimmer, chainsaw tanks then use before laying them up, but during the season the boats tanks may have fuel in for weeks if not months.

I was told by a good garden machinery engineer that modern unleaded petrol starts to jelly after 3 months which seems about right.

 

[onesea]

Buy a fuel preserver, I bought one stopped 95% of my problems with outboards both 2 and 4 stroke. As always with me they where used and abused with minimal maintenance.

When my 3.5hp Tomhatsu 2 stroke went for impeller change and service after 6 or 7 years, the dealer was surprised it was getting old through use not age .

The one I bought (cannot remember which) cost about 15 quid about 6 years ago, I have only just run out.

I was so impressed I now buy a similar thing for diesel inboard.

 

[macd]

Never had sticking carbs on my Mariner 2 & 5;

Never had sticking carbs on anything except a Ducati in which the slides hung up on the cable end fittings and dumped me on my ear on a roundabout in 1976. I've used a lot of engines, two-stroke and four, over the last forty-odd years and am surprised that this seems a common problem for some (unless everyone's suddenly gone retro and is using Castrol 'R'). What's going wrong?

 

[single]

Never had sticking carbs on my Mariner 2 & 5; I religeously empty the tanks every winter - into the lawnmower, strimmer, chainsaw tanks then use before laying them up, but during the season the boats tanks may have fuel in for weeks if not months.

I was told by a good garden machinery engineer that modern unleaded petrol starts to jelly after 3 months which seems about right.

I do the same, but why is the lawnmower ok left all winter? Are lawnmower carbs less fussy about s### fuel?

 

[Lakesailor]

Never had sticking carbs on anything except a Ducati in which the slides hung up on the cable end fittings and dumped me on my ear on a roundabout in 1976. I've used a lot of engines, two-stroke and four, over the last forty-odd years and am surprised that this seems a common problem for some (unless everyone's suddenly gone retro and is using Castrol 'R'). What's going wrong?

I do the same, but why is the lawnmower ok left all winter? Are lawnmower carbs less fussy about s### fuel?

Same here. I have never run outboard carbs empty. Never thrown away fuel. They always started even after months in the garage. I think that once a carb has some gunge in it unless you clean it thoroughly, including a good blast with an air line, you are just putting off the next blockage for a while. Whilst it's the jet that blocks the gunge can form in the passages. Bit like blood vessels and a thrombosis really.

One thing I thought of. Do those getting more problems use supermarket fuel?
I've stopped buying from supermarkets and use brand name fuel stations. You get better mileage, believe it or not.

 

[Seajet]

I do the same, but why is the lawnmower ok left all winter? Are lawnmower carbs less fussy about s### fuel?

No, lawnmowers are just as fussy, our garden centre bloke says Spring is always lucrative with people getting carbs sorted; which is why I said I try to use up fuel in the mower, strimmer & chainsaw before laying them up.