Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 20-09-2013, 10:55   #16
Registered User

Join Date: Oct 2012
Location: UK
Boat: Catana 50
Posts: 76
Re: 2 Stroke vs 4 Stroke

I think colemj makes good points re weight and fuel efficiency, and as I don't intend ever taking the thing off the dink or submersing it, I still have a suspicion that whilst a 2 stroke would be easier to fix, a new 4 stroke won't need fixing. Jury still out.
__________________

__________________
AliaVita is offline   Reply With Quote
Old 20-09-2013, 11:00   #17
Registered User

Join Date: Apr 2011
Posts: 2,243
Re: 2 Stroke vs 4 Stroke

I would consider a 4 stroke if you are doing any extended cruising with the outboard, when the 2 stroke fuel consumption becomes an issue.

For short trips with a dink the 2 stroke does kind of win hands down - unless you don't like the idea of dumping all that oil and unburnt fuel in the water.

Go and run a 2 stroke in a bucket for 5 mins, to see what I mean. The results are disgusting and make me ashamed to have one.
__________________

__________________
MarkSF is offline   Reply With Quote
Old 20-09-2013, 11:04   #18
Registered User

Join Date: Oct 2012
Location: UK
Boat: Catana 50
Posts: 76
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by MarkSF View Post
Go and run a 2 stroke in a bucket for 5 mins, to see what I mean. The results are disgusting and make me ashamed to have one.
So what would you replace it with if you had to do so next week?
__________________
AliaVita is offline   Reply With Quote
Old 20-09-2013, 11:13   #19
Registered User

Join Date: Sep 2012
Posts: 4,936
Re: 2 Stroke vs 4 Stroke

I truly understand folks who have a problem with the additional oil of a 2 stroke. Mind you at 100-1 its not much but I understand. Many of those folks choose to drive electric cars or take the bus and sail like the Pardey's with a rowing scull rather than a dirty diesel engine, as well they build super hi energy efficient homes that can be heated by natural means and use solar power and if your one of them then i take my hat off to you. Now if you get disgusted real easy and feel shameful but still burn gas on the water then its a bit hypocritical don't you think??
__________________
robert sailor is online now   Reply With Quote
Old 20-09-2013, 11:54   #20
Registered User
 
Dos Gatos's Avatar

Join Date: Nov 2011
Location: SF Bay
Boat: O'Day 25
Posts: 100
Re: 2 Stroke vs 4 Stroke

For cost, compare $$$ of a second hand 2 stroke + gas to a 4 stroke + gas for 100 hours. You do the math. It changes every year. At one time used 4 strokes weren't readily available so the disparity of purchase + operating cost was greater.

I like that 4 strokes are more quiet.

I like that you can swamp a 2 stroke and have it running in 30 minutes.

As far as emissions, if I truly cared about the environment I wouldn't have a boat.
__________________
Dos Gatos is offline   Reply With Quote
Old 20-09-2013, 12:07   #21
Registered User

Join Date: Apr 2011
Posts: 2,243
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by Dos Gatos View Post
As far as emissions, if I truly cared about the environment I wouldn't have a boat.
The problem is, if we all really cared about the environment, we should all kill ourselves. All human activity has an impact, the trick is minimising it and/or keeping it to an acceptable level.
__________________
MarkSF is offline   Reply With Quote
Old 20-09-2013, 12:10   #22
Registered User

Join Date: Apr 2011
Posts: 2,243
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by AliaVita View Post
So what would you replace it with if you had to do so next week?
I'd replace it with a 4 stroke I think. I've had one before, it was fine. But for my application where it gets run for maybe 4 hours a year, it's not worth replacing unless it gets stolen.

The problem with 2 strokes isn't just the oil. Up to 30% of the fuel goes unburnt out of the exhaust. So at 100:1 mixture, for every ounce of 2 stroke oil, you're dumping 30 ounces of raw gasoline into the water.
__________________
MarkSF is offline   Reply With Quote
Old 20-09-2013, 12:18   #23
Registered User

Join Date: May 2009
Location: Massachusetts
Boat: 40' Silverton Aftcabin with twin Crusaders
Posts: 1,589
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by Roy M View Post
Well put, colemj. A lot of folks don't tend to add up the hidden weight and hidden cost of all that wasted fuel.
Those concerns are important to few. Not being able to lift a heavy 8 or for that matter a heavier 9HP off one dinghy is important to many.
__________________
foggysail is offline   Reply With Quote
Old 20-09-2013, 13:20   #24
Registered User
 
Wraith_Mac's Avatar

Join Date: Aug 2013
Location: Central Coast, NSW, Australia
Boat: Avon Rib, 65hp
Posts: 304
Re: 2 Stroke vs 4 Stroke

The OP was asking for a solution to outfitting a Catana 50' catamaran with a 15-20hp dink engine... 2s or 4s?
In that context, smaller outboard issues do not seem to be relevant to the question at hand do they?
15-20hp 2s or 4s can be manhandled by some but are usually left in situ on a cat, yes? Mechanical advantage can be used to bring them inboard if necessary.
FWIW, I have a 65hp 2 stroke, [not suggested for dink use] it's from the last century and still a great engine, very reliable. The Suzi DT65 has served me very well for over 20yrs. If anyone has reason to be a fan of 2 strokes it is me.
However tech moves on and if ever I have to replace it it will be with a 4 stroke 40 or 50hp fuel injected engine. Either will provide enough performance much more economically.
All the positives of 4 strokes have been listed above and as all the car engines I work on [hobby] are 4 stroke the technology doesn't frighten me, it's a myth really.
I can see the 2s still has big advantages in small motors, but the OPs requirement is either 15-20 hp, then it's a 20hp FI 4 stroke for me, the extra weight won't be noticed on the Catana.
It's going to hang from a big cat, electric start 20hp with a good sized hard bottomed Hypalon dink, why not?
Cheers,
Mac
__________________
Wraith_Mac is offline   Reply With Quote
Old 20-09-2013, 13:28   #25
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: 2 Stroke vs 4 Stroke

For the record, I have never mentioned environmental concerns when discussing this issue - it isn't on my list of comparable features for cruising. I dump far more gas into the environment trying to fill a portable gas tank on a beach from a cracked handle-less 10gal pail of fuel provided by the vendor.

I think the continual political bent of comparing 4-stroke owners with electric cars, buses, rowing sculls, high efficiency homes, solar, etc gives us much more insight about your personal demons than it does to the choices of an outboard.

Like I mentioned, if weight is a concern, then you should not be looking at a 15hp of any type. The weight difference at 15hp+ is simply inconsequential. In fact, above 15hp, it begins to favor 4-strokes. I stated that for smaller engines (3-8hp) that needed to be lifted and carried regularly, a 2-stroke was the better choice.

If you keep water out of the engine by using a good external fuel filter/water separator, you will not have much need for "fixing" anything on either type of engine. Just what do people think goes wrong with these things that need constant "fixing"? Carb rebuilds are the same for each, so are props, plugs, water pumps, pull cords - even magnetos and charging circuits.

How many of you find yourselves regularly completely stripping and rebuilding your outboards? Those that do will be better off with a 2-stroke - but best off with a set of oars.

If you polled serious offshore cruisers (if you could even objectively define that term), they would give answers that are decades out of date - with opinions formed decades ago on gear that no longer exists now - just as they do with anchors and sails and other gear. For example, the most popular anchor listed in these polls is the CQR. It took decades before roller furling gear were accepted in these polls.

And people who are mostly doing long passage making aren't the best judges of an outboard. Polling recreational fisherman would probably be a better idea.

Local fishermen in many parts of the Carib have Yamaha 15hp Enduros because they are made inexpensively in that part of the world and their governments heavily subsidize their purchase. Do those facts alone make them the best choice? It seems that many put a lot of emphasis on "what the locals use", and conflate their choice with some "secret knowledge".

I don't understand the point about a 2-stroke being good for short trips. All outboards are mostly used for short trips. Both types are fine for this, and both are designed for this. A 4-stroke is much better at trolling or low-speed work.

We just got a new outboard. Our previous one was a 4-stroke. We debated long and hard about going to a 2-stroke and actually ordered one. That order/delivery got screwed up and we didn't accept the engine and went back to square one. A year later, we took ownership of a new 4-stroke. What the decision came down to for us was the weights were almost equal, we got 5 more HP in the 4-stroke, we can have a conversation while planing at high throttle, and most of the areas we cruise in have very little to no availability of gasoline.

That last part is very important because we spend months in areas with no gasoline at all, and years in parts of the world with difficult access to gasoline. When in these areas, we carry less than half the gasoline on board than friends with 2-strokes - a couple of jugs in a sealed, vented locker versus an entire side deck lined with jugs (which are sometimes stolen).

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 20-09-2013, 13:31   #26
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by Wraith_Mac View Post
It's going to hang from a big cat, electric start 20hp with a good sized hard bottomed Hypalon dink, why not?
Cheers,
Mac
Our cat is only 40', but we have a 12' hypalon RIB with an electric start fuel-injected 20hp. Sounds like we came to the same decision as you.

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 20-09-2013, 14:12   #27
Registered User
 
Wraith_Mac's Avatar

Join Date: Aug 2013
Location: Central Coast, NSW, Australia
Boat: Avon Rib, 65hp
Posts: 304
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by colemj View Post
Our cat is only 40', but we have a 12' hypalon RIB with an electric start fuel-injected 20hp. Sounds like we came to the same decision as you.

Mark
One of us must be smart Mark and I'm told it isn't me!
I do have a lot of hours in Hypalon ribs though, usually in places cruisers wisely avoid and some I should have.
You're cruising and I'm waiting for my wife to cease being 'indispensable' at the University, so it must be you brother.
Cheers mate,
Mac
__________________
Wraith_Mac is offline   Reply With Quote
Old 20-09-2013, 14:18   #28
Registered User

Join Date: Dec 2012
Location: Sydney, Australia.
Posts: 170
Re: 2 Stroke vs 4 Stroke

15 horse yamaha two stroke. light, fast, simple and in the very likely event of swamping the motor you can have it running in a jiff. 8 horse if you must. Parts available everywhere and seen all over the world. The only motor you will see in PNG is the 15 horse two stroke yamaha and I suspect it is the same all over the south Pacific.
__________________
giant is offline   Reply With Quote
Old 20-09-2013, 14:39   #29
Registered User

Join Date: May 2009
Location: Massachusetts
Boat: 40' Silverton Aftcabin with twin Crusaders
Posts: 1,589
Re: 2 Stroke vs 4 Stroke

Quote:
Originally Posted by Wraith_Mac View Post
The OP was asking for a solution to outfitting a Catana 50' catamaran with a 15-20hp dink engine... 2s or 4s?
In that context, smaller outboard issues do not seem to be relevant to the question at hand do they?

Mac

8-9HP 2 stroke vs 4 stroke, 15 2 stroke vs 4 stroke, 30HP 2 stroke vs 4 stroke are all relevant Mac. In all cases a 2 stroke is lighter. So the difference in fuel consumption IMHO is no where near as important to many where as weight might be. Of course if the engine is mounted once and stays put for years until it needs replacement then maybe fuel soars on the importance list of choice options.
__________________
foggysail is offline   Reply With Quote
Old 20-09-2013, 14:52   #30
Registered User
 
sy_gilana's Avatar

Join Date: Jan 2005
Location: On board
Boat: Van de Stadt 50'
Posts: 1,101
Send a message via Skype™ to sy_gilana
Re: 2 Stroke vs 4 Stroke

Hi If you are looking for a 2nd hand Yamaha 15 in the EU you will struggle to find one.
In the EU they are sold as 13.5HP, although it actually IS a 15 with a subtle difference to comply with licensing requirements (same situation as 9.9)
for example this link..
MIL ANUNCIOS.COM - Motor yamaha 13,5 Nuevo sin titulin
IS for one for sale in Spain.
__________________

__________________
Tight sheets to ya.
http://gilana.org
sy_gilana is offline   Reply With Quote
Reply

Tags
2 stroke, 4 stroke

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.