2 Stroke or 4 Stroke?
I'm sure this question has been asked plenty of times but the search option on this site didn't help me find a previous thread.
I've always been under the impression that the 2 strokes, though have their good points like longer periods between servicing, didn't last as many hours as a 4 stroke and had the fumes issue (which makes me sea sick).
Now after being down at the boat show today, i've been told that they emit the same level of fumes as a 4 stroke now due to the stricked emissions regulations put on them and that they last the same number of hours as a 4 stroke.
If anyone can confirm this to be true and also what year model Evinrude e-tec started being produced with these low emissions as I don't want to end up buying a boat with a 2 stroke and then not being able to use it because of the fumes.
Also if anyone has other info on the good and the bad with relation to either motors.
And last but probably not least, what are peoples thoughts on having one motor or two...
... and if you buy a boat with 2 motors, when they give up the ghost, can you stick a single one on it?
Thanks in advance.
till
Posts: 9358
Date Joined: 21/02/08
How big a motor? I have to
How big a motor? I have to admit I'd probably not buy a 2st above 120hp?
They can't be producing the same fumes, one is burning oil, the other isn't thatis just marketing.
Its usually easier to go twins to single than single to twins!
Grooveepants
Posts: 194
Date Joined: 06/03/10
Two 115hp Evenrude Etecs
Two 115hp Evenrude Etecs
PerthGlory
Posts: 157
Date Joined: 07/03/10
answer your phone
ring ring....ring ring
dodgy
Posts: 4585
Date Joined: 01/02/10
Its all relative. Some older
Its all relative. Some older hulls were built for a screaming 2 stroke and dont perform with the extra weight of a 4. (4 strokes are really closing the gap on weight though)
Length a motor will last will have a lot more to do with how well it is maintained and the type of use it does than if its a 2 or 4 stroke. Despite what you may be told there are plenty of 4 stokes that fail within 1000 hours and plenty of 2 strokes that are still going after several thousand.
As far as fumes go, you will still get the odd whiff of burning oil from any 2 stroke in certain conditions. I find mine does get a build up after 4 or so hours of trolling and if Im heading downwind I can get a whiff.
Does anyone know where the love of god goes, when the waves turn the minutes to hours?
sea-kem
Posts: 15041
Date Joined: 30/11/09
I've just built a fuel tank
I've just built a fuel tank fro a boat that has gone fom 2 donks to one....goes like a shower of shit. With the advance of technology I reckon it's going to be hard to decide which way to go. More a case of what suits your fishing needs.I have a 90hp 4 stroke on my 5.4 Quinnie. Absolutely love it. Quite, fuel efficient but probably heavier than a 2 stroke.
Love the West!
Travisd
Posts: 315
Date Joined: 07/05/11
can of worms
I have the 4 stroke 115 yamaha.. and we've got a 25HP two stroke yamaha... both are mint motors but anything bigger than a 90HP on anything I'd go the four stroke for sure.
Not big on the 2 motors .. just from all the extra servicing costs. An auxillary would be better if you were going somewhere remote. I think all of your brands out there are pretty good these days
.Can't see why if amonohull boat had two motors to start with, you could drop one and repower with a single bigger one.. you coundn't go the other way around though(single to twins) without reinforcing the transom
Baron Sportsman
Just the depth that Varies
Jamos Damokos
Posts: 239
Date Joined: 11/08/11
e-tecs for me, and next boat
e-tecs for me, and next boat will be twin etecs 150 or above, will admit you can smell a slight oil/fuel smell every now and then. only going on what i know of motorbike engines and a new age 4t cost more in service/maintenance due to more moving parts and higher rpm, as for outboards i dont think this is relevant they probably rev less but would still assume maintenance costs to be higher due to more parts. i think the 2t 4t debate is more of a what your using the boat for and what your preferance is. and as for why i want 2 motors, well if one craps itself theres always the second..... basicly for piece of mind.
Twiddling my thumbs with velvet gloves on.
smash
Posts: 434
Date Joined: 01/12/10
at the show
there was an Etec idling in a drum-could definitely smell the oil, not strong but there without a doubt.
Had a spin on the Merc 150 there, was definitely a nice motor, solid feel and lots of torque. No price on it yet though-"between a Opti and a Verado was the cryptic answer.
Of all the outboard sellers though, merc was the only one that didnt concentrate of running down the others.
Grooveepants
Posts: 194
Date Joined: 06/03/10
Yep
I saw that too and sent the missus over for a sniff and she said she could smell it too. I currently have a Honda 90hp and you can get a wiff of the fumes off that sometimes too. It's just that I've been out on an old boat that had a 2 stroke and it was horrible but again, everyone is saying the new emissions controls on stuff coming out of America means they have less fumes than 4 strokes.
till
Posts: 9358
Date Joined: 21/02/08
Sure, but think about the
Sure, but think about the implications of that?
The less oil they're burning, the less lube they're getting.
Its like people getting excited about the weight coming down on 4st. It just means that the castings are like tinfoil.
allrounder
Posts: 1853
Date Joined: 10/11/08
Getting the weight down doesnt always mean its build
weaker Till it just means its built differently.
So tell me have you got your info from years on the water or hours on the internet?
till
Posts: 9358
Date Joined: 21/02/08
That may be true. Looks at
That may be true.
Looks at what happens to lightweight marine diesls though! Hard to see how 4st engines would be somehow immune to all the same issues there.
The industry has created diesels with the longevity of 4st motors and next will be 4st motors with the longevity of 2st motors.
allrounder
Posts: 1853
Date Joined: 10/11/08
All it would take is for the likes of BMW or Mercedes
to get serious about it and that would be a different story as well though.The engine mould injection systems they are using are producing lighter stronger diesels than ever before.The new 2 litre they are putting in the 520d BMW is mindblowing for a little oil burner.
So tell me have you got your info from years on the water or hours on the internet?
till
Posts: 9358
Date Joined: 21/02/08
I fundamentally
I fundamentally disagree.
Its not a secret that the more HP you crank out of the same weight block, the lower its life expectancy is.
Neither BMW or Mercedes are magicians and in terms of longevity car motors are irrelvant, they just don't do the hours!
This is from a website that has a bit of a natter about the issues.
The Problem With Light Weight Engines There is a direct relationship between service life and the weight of engine blocks and cylinder heads. The heavier, or thicker the castings, the longer they will last. That's one of the reasons why older engines just seem to go and go, while we often refer to the engines of recent years as "throwaways."
The problem with light castings is a problem of both strength and heat distribution. Diesel engines, with their 350-550 lb. internal cylinder compression, develop tremendous heat within the cylinders and heads. When castings heat up they expand, and when casting thickness are unequal, this can lead to cracking. It follows then, that the thinner the casting, the weaker it is, and therefore more prone to heat distortion and cracking.
This has been one of the major problems of trying to adapt light weight automotive engines to marine use. Because the loads are much greater, more heat is generated, and therefore more distortion of the castings occur. And when distortion occurs, the close tolerances of the moving internal parts such as crankshaft, bearings and journals, rods, pistons and cylinder walls goes out of whack. The end result is an early demise of the engine. Therefore the move to adapt high speed, light weight small truck engines to marine use results in an engine with a decidedly shorter service life. One of the most common problems that we see with light engines is the frequent cracking of cylinder heads, which is the first place that designers seek to reduce weight.
allrounder
Posts: 1853
Date Joined: 10/11/08
Same old story of goggle not giving the full story
The engine development from the likes of BMW for their cars that a designed to run long distance at far higher speeds than here is fantastic.They use two stage injection systems to produce stronger lighter engines than ever before.I will also state that it is a strong chance that we will see diesel outboards in our life time.The statement you have spent time trying to find states that when casting thickness are unequal it can lead to cracking.This is true but if they are produced with the quality of todays machinery then this doesnt occur.These engines are produced to drive at 200+ kms an hour and will do it every day of the year all day if required.If they built a diesel outboard the size of a 250 Honda/Suzi/merc ect it would be on the back of my boat in a heartbeat.
So tell me have you got your info from years on the water or hours on the internet?
sea-kem
Posts: 15041
Date Joined: 30/11/09
ah it all comes back to basic
ah it all comes back to basic physics guys you can't take from Mary to pay Paul. I've just read a book on it and it's a fundamental law that can't be cracked.
Love the West!
sea-kem
Posts: 15041
Date Joined: 30/11/09
Ah it's the basic laws of
Ah it's the basic laws of physics. You can't take from Mary to pay Paul.
Love the West!
allrounder
Posts: 1853
Date Joined: 10/11/08
But now days you can turn Mary into Paul
and Paul into Mary.
As we move forward things are a changing.
So tell me have you got your info from years on the water or hours on the internet?
sea-kem
Posts: 15041
Date Joined: 30/11/09
Ha ha I think you're a bit of
Ha ha I think you're a bit of a romantic Allrounder
Love the West!
Jamos Damokos
Posts: 239
Date Joined: 11/08/11
with the quality of oil and
with the quality of oil and better more effecient engine designs these days it allows less to be needed and a boat engine rarely sits above 5000rpm for prolonged periods. but in the end you will always sacrifice engine longevity for performance more oil, more protection, less performance and vice versa, since oil is injected rather than mixed with the fuel in the tank alot less waste oil is produced and allows for better performance while still providing optimum lubrication....
Twiddling my thumbs with velvet gloves on.
badxr8ute
Posts: 65
Date Joined: 03/09/08
Mate i have twin 250 etecs on
Mate i have twin 250 etecs on my boat and i can honestly say i have never noticed any fume smells. Love the performance of the etecs!
Would never go a single motor. Pushing a 31 footer is no easy task even for 2 outboards.
Was at the show myself today and found my next boat. Lurhs 37ft Open Tower. Awesome!