Outboard Advice

[charliedrewitt]

Hi,

[I posted this about three days ago before my account was approved, so it seems to have dropped off the radar without anyone seeing it, so I'm optimistically re-posting it]

We have a Fletcher Arrowstreak 17 with a 125hp Mercury. We're wanting to upgrade to a 150hp, either an e-tec or a four stroke.

We've seen a couple of suitable engines, the problem being that all the ones we've seen have 25" shafts, and after some measuring we think our outboard is 20". What would be the downsides to fitting the longer shaft motor?

Also, a chap selling an e-tec has said he can adjust it from 25" to 20", has anyone heard of this being done before and is it likely to have implications? I had assumed that the shaft was a built in part of the motor.

Many Thanks in advance

Charlie

 

[VicS]

First determine what shaft length you need.

The anti-ventilation plate above the prop should be close to the level of the bottom of the transom

http://www.smalloutboards.com/shaft.htm will give you some guidance.

If the shaft is too short then the prop will ventilate and you may also lose cooling.
If the shaft is too long it will create excessive drag.

Without full model details I cannot say what a change from extra long ( 25") to long (20") would involve.
It is perfectly feasible but is unrealistically expensive as a rule unless the parts are already available. Maybe the vendor has already altered it from a long shaft to an extra long and has the parts available to convert back again.

The model number will tell you which it was originally ( X= extra long, L= long)

Two stroke (E-tec) will give faster acceleration than a 4 stroke.

 

[charliedrewitt]

Thanks for the reply and information VicS.

Do you know what sort of tolerance is acceptable between the level of the plate and the bottom of the transom. For example I've just measured the transom at 22.5", suggesting that a 25" shaft outboards anti-ventilation plate would be 2.5" below the bottom, is that too much? Our current outboard seems to be about an inch above the level of the transom.

I don't know the model as it's not specified on the advert, except that it's a 2007 Evinrude E-Tec 150hp. I guess the chap must have the parts as he said it would be no extra charge. I'll ask him for the model number.

Again, thanks very much.

Charlie

 

[VicS]

I expect that if you measure a 20" engine you will find that the AV plate is actually a bit more than 20"below the transom top. It could be around 22". That would be OK.
Simiarly a 25" model may measure nearer 27" to the AV plate.

I'd recommend that you take a tape measure with you when you look at it

model numbers for 2007 150 hp Evinrudes are

E150DBXSUF
E150DCXSUC
E150DCXSUF
E150DHLSUC
E150DHLSUF
E150DPLSUC
E150DPLSUF
E150DPXSUC
E150DPXSUF
E150DSLSUC
E150DSLSUF

E= Evinrude, 150 = 150, D = E-tech, B= blue paint, C= counter rotation, H= lightning gearcase, P = power trim and tilt, S = saltwater edition (20" transom) X=25", L= 20", SU = 2007. The last letter is production suffix.

There maybe other letters to indicate the country of manufacture, eg B for Belgium


As far as I can see changing the length would involve changing the drive shaft and the exhaust housing, the main outer part of the leg, and a few other minor parts such as the gear shift rod.

However these big engines are a bit outside my area of interest!

 

[Fire99]

Will there not be weight issues?

I'd guess a modern 150hp 4-stroke will be significantly heavier than an old 125hp 2-stroke.

(That is if looking at them is anything to go by, or my 10hp 4-stroke honda which is about double the weight of a comparable 2-stroke)

 

[landlockedpirate]

IMHO the Etec is the best engine for your boat, but you must get one with the correct shaft. If you dont at best it will compromise performance and at worst will make the boat handle in a dangerous way.

If the seller can change the leg back (perfectly possible and safe with the right parts) then let him do it and buy the Etec. They have better power to weight ratio, good fuel economy, smooth and quiet in operation, as mentioned because they are 2 stroke they are also lighter than the 4 strokes.

 

[VicS]

In terms of weight

A 150 Evinrude E-Tec weighs 190 kg,

a 150 2 stroke Mercury Optimax weighs 201 kg,

a 150 4 stroke Mercury Verado weighs 231 kg.

 

[owen-cox]

I was thinking that surely the difference in weight of a 4 stroke is outweighed by the fact you will need at least double the fuel for a 2 stroke?

 

[Fire99]

I was thinking that surely the difference in weight of a 4 stroke is outweighed by the fact you will need at least double the fuel for a 2 stroke?

I wasn't thinking of fuel, more that if the 4-stroke was (for argument sake) near double the weight, that would affect boat balance, with it hanging off the back of the transom.

That said, from Vic's info, they seem much of a muchness.

I'd be interested the weight of the original 125hp 2-stroke is though, as a comparison.

 

[prv]

I was thinking that surely the difference in weight of a 4 stroke is outweighed by the fact you will need at least double the fuel for a 2 stroke?

Fine, but you can put that weight in a better place for trim purposes than hanging it off the stern.

(Not that I'd want to pay for more fuel than I had to these days, but that's a different question.)

Pete

 

[VicS]

I'd be interested the weight of the original 125hp 2-stroke is though, as a comparison.

We do not know exactly what model but a 2001 125hp 2 stroke Merc weighed 158kg

 

[Fire99]

We do not know exactly what model but a 2001 125hp 2 stroke Merc weighed 158kg

Blimey... Engines have got heavy old hectors over the last decade or so. That's a fair ol difference.

 

[charliedrewitt]

Cheers for the replies all.

I think we're gonna go for the etec, if I can ever get hold of the bloke, seems like boats & outboards go out of thier way to make sellers difficult to contact!

According to what I've read, the e-tec use a similar amount of fuel to a comparable four stroke, or is this just advertising blurb?

For those who were interested, according to a dealer I spoke to the 125hp 2 stroke weighs 157kg. I'm not too worried about a 30kg difference, but this puts me off going for a 4 stroke a little bit.

Cheers

Charlie

 

[landlockedpirate]

Etecs are very fuel efficient, not quite as good as a modern 4 stroke, but not far off. I used a 90hp Etec on an 18ft centre console, very very impressed with it. For a 'speed boat' application I think they are the best choice by far.

 

[longjohnsilver]

I was thinking that surely the difference in weight of a 4 stroke is outweighed by the fact you will need at least double the fuel for a 2 stroke?

Not with the Etec you don't, it's just about as efficient as a 4 stroke. Had one recently, a great engine, started first turn of the key everytime and very fuel efficient.