4stroke vs 2stroke

Gmarkos319

Seaman Apprentice
Joined
Apr 9, 2005
Messages
41
Are there any big disadvantages to 4stroke engines? I like the idea that you dont have to change the oil everytime you fill up and 4strokes are much quieter but why doesnt everyone use them then? there has to be some catch that im not getting lol. Any help would be great.
 

31900

Petty Officer 2nd Class
Joined
May 23, 2003
Messages
167
Re: 4stroke vs 2stroke

To get the same power a 4 stroke is much heavier. There are more service requirements when compared to a basic pre-mix 2 stroke. Even some 2 strokes such as those with fuel and oil injection require a good deal of servicing. My choice is a basic premix 4 stroke as in the Yamaha Enduro range. Tried and true technology and very little to go wrong.
 

Triton II

Commander
Joined
Nov 23, 2004
Messages
2,479
Re: 4stroke vs 2stroke

G'day SSS,<br /><br />I have a 2003 model FT60B Yamaha 4-stroke which has done 300 or so trouble free hours on the back of my 16ft aluminium cuddy cabin. It weighs about 30lbs more than the equivalent Yamaha two-stroke. The maintenance is simple and the engine is very quiet and smoke free at idle. I think people still buy two-strokes because they're cheaper to buy - but IMHO they're definitely more expensive to run and are not as quiet. I think $10 worth of oil and a filter every 50 hours is worth the hassle of the 4-stroke as the thing only uses about 4 gallons of fuel an hour at 25 kts. My cousin's 60 hp Johnson 2-stroke uses double that in a 15 ft Savage aluminium runabout. What he saved in purchase price he's paid for in fuel consumption and now I'm ahead! Your choice but don't be put off by extra maintenance - it's not at all hard.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 4stroke vs 2stroke

Non-repair topic.
 

ziemann

Chief Petty Officer
Joined
Apr 28, 2004
Messages
584
Re: 4stroke vs 2stroke

Use the search function. This horse has been beaten to death. There are dozens and dozens of pages on this subject (going back several years) without starting this thread all over again. <br /><br />But watch...people won't be able to resist the urge to post to this thread all over again...hehe.
 

khc1970

Petty Officer 2nd Class
Joined
Sep 19, 2004
Messages
109
Re: 4stroke vs 2stroke

Whatever you do, make sure you compare like with like, and not a 10 years old 2 stroke with a 2005 4 strokes or the other way round.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: 4stroke vs 2stroke

Modern 4 strokes are great motors but with just too many moving parts.This has to add up to more maintenance expense down the line.<br />Modern 2 strokes, the Etec for instance, are as good or better on all points except sound as a 4 stroke.And I wonder if that sound problem comes from the 2 stroke getting twice as many power strokes per revolution as a 4 stroke.Now that the Etec has come along you will see more companies with similar technology.<br />Look long and hard at both and make your choice.<br /> Try to sort out the gobble D goop that will come from both camps.
 

bigbrownbuku

Master Chief Petty Officer
Joined
Sep 17, 2004
Messages
885
Re: 4stroke vs 2stroke

the major difference between 2 identical boats fitted with like 4s/2s engines will be holeshot performance. aside from all the obvious things like noise smoke etc.<br /><br />4strokes are quieter<br />4strokes are far less "smoky"<br />4stroke/2stroke weights are comparable<br />service costs are more similar then you would be led to believe.<br />2strokes are faster out of the hole.
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Re: 4stroke vs 2stroke

I guess you are talking buying a new motor so the above comparison of a 60hp yamaha 4 stroke and 60hp Johnson 2 stoke needs explaining. The Johnson is probably old 2 stroke carbed or ficht technology and not apples to a 2003 x 4 stroke. Go compare the 2005 60hp 4 stroke with the latest 2005 technology eTec 2 stroke and the numbers aren't as convincing for the 4 stroke. <br /><br />Forget the $$$ for now and consider how much your free time is worth and which maintenance items you want to do. Change oil/filter and adjust valves on a 4 stroke or pour oil into a 2 stroke tank (take into consideration that you may want to check the 4 stroke oil dipstick often and that somewhat cancels out time spent pouring oil in 2 strokes)? Don't forget the spent 4 stroke oil has to be properly disposed of...is that handy or a hassle? Do you want to pay someone to maintain the 4 stroke or do you want to spend a Saturday morning every xxx hrs doing it yourself? If a shop does the work for you how much time are you spending trailering and picking up from the shop? Some guys like to adjust valves and change oil...I'm lazy and would rather be boating while I pour 2 stroke oil.
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: 4stroke vs 2stroke

the vapor seperator on the HPDI containes the medium pressure electric pump. it has a filter that needs to be cleaned or replaced annually or every 200 hours of service. the medium pressure filter between the VST and the high pressure pump is annually or 200 hours but its a disposable inline cartridge type. you will need the correct clamps and the clamp pliers to change it. I have seen worm gear type clamps fail and allow the fuel line to pop off. at 50 PSI it sprays a bunch. the pump kit is about 60 dollars the t-stats are about 30 and the pressure valve grommet is 2.50 or so. the oil tank water trap needs maint as does the remote oil tank filter.there is also a small oil filter between the VST and the oil pump. if it has the dual electrode plugs ( gray coil connectors) you will need a .024" wire feeler gauge and the picture in the 03 tech guide to set the gap. most the maint is monkey work. anyone can do it. but it does require patience and the ability to follow directions from print.the low pressure fuel pumps are about 40 dollars apiece. the O2 sensor needs maint at 75-100 hours and if neglected will fail. its about 370 or so.
i am getting the inpression that any modern outboard is going to need time at the dealer and not be cheep to keep running<br /><br />tommays
 

Whitedog

Cadet
Joined
Jul 3, 2005
Messages
12
Re: 4stroke vs 2stroke

2 strokes are lighter and more powerful than their 4 stroke counter parts. Something to consider on a boat where weight is a critical factor. Maintenance cost is a small factor, just how much maintenace will you do to an outboard. not a whole lot I'd guess. Performance and weight are the overiding factors.
 
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