2 stroke vs 4 stroke

[macd]

Whether they're messier or not probably depends on how well and where you mix the 2-stroke's oil, and how incontinent or not your 4-stroke proves to be. The point's moot, but most people accustomed to car engines would probably consider a pre-mix stroker a bit of a hassle.

As to durability, the "at least in theory" part didn't creep in there by accident. In general terms, four strokes damn well ought to be more durable. Just ask the next main bearing you happen to strike up a conversation with where he'd rather be. In practice, of course, what does for most marine engines is the salt environment and general lack of care, rather than subtleties (or not-so-subtleties) of design. That's one of the reasons I asked the original poster what exactly had corroded.

 

[kirielad]

Tohatsu are so confident of the durability of their 2 strokes that the factory warranty allows for and includes usage for racing (Zapcats, etc). I guess a lot of it is down to personal choice, but to me 4's are more complicated, have more parts, more to go wrong, more to service, yadda, yadda, yadda. I have experienced a 4 str Honda generator which packed up due to coaked up valves as the the mixture was a bit out.

 

[geoffatstanpit]

One more on this veritable pile of wisdom! The previous owner of my Parker 21 used a Mariner 5 2stroke but got fed up with the way it stalled on him just as he wanted to exit the lock at Chi Marina and bought a Merc 5 4stroke. Then he decided to sell me the boat with both engines. So I compared them. The Merc certainly does tick over more reliably than the 2st. I didn't get a chance to test the relative fuel consumption but the Merc ran for 15 hours on 12 litres all the way back from Cherbourg and I can't see a 2st doing that. But - with only one bang every other rev the power is noticeably rougher than 2sts I've tried - 15 hours was about as much as fur and flesh could stand and all manner of screws undid themselves!

 

[reginaldon]

Sticking 50ml of oil in a 5l can and shaking it is hardly a hassle ie. 100:1. I got 10 hours from 12.5 L in my Yamaha 5.

 

[Csail]

Honda 4 stroke is rubbish....ive got one....customer support the same. Go for Tohatsu.

 

[Noddy]

I'm running a 30 foot cat with a 2 stroke outboard.

Last summer, for our club trip to Ostende, there was very little wind (one isobar in Spain the next in Norway). At the start we were about to make the decision to hug the coast in the sea breeze and get some proper English beer.

The reason was the painful fuel consumption of the 2 stroke. I would have spent a lot of money motoring all the way to Ostende for something that falls well short of Real English Bitter.

In the event my mate Ed towed me all the way across behind his concrete smack.

I won an award for the greenest trip across.

So I'm in the market for a single 10 - 20 hp long shaft 4 stroke and have a very nice (if a little thirsty) 9.9hp Suzuki two stroke for sale!

What about Diesel Outboards??

 

[Bejasus]

Diesel outboards few and heavy and expensive.
I have just purchased a Honda BF20 plus Powerthrust Prop and Electric tilt & start. It is identical in every way to the BF15 just more power. I haven't used it yet, but it is a very popular unit in the US and as I got the 20 for about the same price as the 15 I couldn't really complain.

 

[ReggieK]

Hi Macd

I am told that the manifold & sump have corroded, there is 8 weeks delivery on the sump. Also advised that this is a common problem with this unit, especially when used as an auxiliary

 

[ReggieK]

Hi Lakesailor
Do you get the same amount of push from the 4HP Yamaha?
My main usage is in and out of marina but I need the capacity of returning home if wind dies & to maneouvre in the stronger winds

 

[Lakesailor]

I tried my handheld gps on-board Slippy (18ft) and get 6 MPH at a little over half throttle. Full throttle makes little difference as I've reached boat speed, but makes more noise and the stern sits a bit lower for about half a mile an hour more.
It manages 4.5 MPH at about quarter throttle. I would say, subjectively, that it is every bit as effective as the Honda 5 HP I had. Plus it doesn't die when you are manouvering onto your mooring, which is the whole point of having an outboard. If you can't rely on it at that point, then it's no use.

 

[ReggieK]

Thanks for that.
Have been offered a good deal on Johnson 4HP 4 stroke and reckon it will probably do the job.
Our marina is very awkward with narrow channels, cutting out & difficult gear change a no no.
I would reckon that Etap is a bit heavier than Slippy, which, I note from another post you have stripped out but I think will get enough poke