the laying down of four strokes

dylanwinter

dylanwinter

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www.keepturningleft.co.uk
on my recent PBO play day I noticed that the eight outboards we tested were very particular abut the way they want to be laid down

although all were handles to the port side.... why... half wanted to be laid handle down and half handle up

why can't they make a four stroke that can be laid down or even turned upside down without leaking oil or wrecking a spark plug

I am onlly a simple ag engineer so I know only the basics

help me vic

D

https://www.youtube.com/watch?v=0afiWy2y-Uc
 
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I'm having my first season with my 4 stroke on the yacht. Last year l bought a 4 stroke for the tender and was impressed enough to change the other motor for a 4 stroke.

When not in use on the yacht the new 4 stroke spends its life laid down, correct side down, in a locker with the propellor end facing the stern. What l have noticed is that the new motor is quite smoky to start with which l don't get with the tender's 4 stroke which by the way except for being transported in the car spends it life upright in the garage. I'm not sure why it might be a little smoky on starting up but one low water when the boat was aground l noticed it had settled on the mud with the bow slightly in the air because of the mud bank it sits on and wondered if it settles the other way (and then the propellor would be raised higher than the motor) could oil be running the wrong way or to do this would you need to literally turn it upside down?
 
The oil must stay in the sump
imagine any engine turned upside down then the oil will leek past the pistons into
combustion chamber...not good
but its not hard to follow instructions about this is it...
 
Thanks Vic. I'm going to try as you suggest and place some wood underneath the power head to see if this makes any difference. Unfortunately the option doesn't exist to leave it mounted upright all the time.
 
Just a minute.
Have you (any of you, not aimed at any one in particular) noticed that most outboards (including 4 strokes) have two tilt settings so that you can leave the motor slightly tilted or at about 50°?
They are absolutely fine like that. My last motor and current motor don't object.
Even if you have steering swivel on, the tilt doesn't cause catastrophic and lasting damage.
If you know about engines you'll know that 2 strokes do not have a sump with a volume of oil at the bottom.
4 strokes do.
They also have valve gear and a camshaft to operate the valve gear. Normally the side that has the valve gear will have an open chamber through which the oil could run if laid on that side. One valve will normally be open at most points of the cycle so oil will have free access to the cylinder via that route. It only has to run down the oil stem. If you are really determined you could let the oil run back up the bores past the pistion rings. But that would take some definite effort.
As Niander says, each engine has it's own foibles and requirements which are laid out in the handbook and the usually on the motor itself.
If you can't be arsed to learn those requirements. More fool you.

If you prefer a stinky, fuel-hungry oil burner, just because you don't have to learn how to treat it. Fine.
 
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Possibly as you suggest, but not in one I've had. Each engine is different and that is exactly the point.
Read the manual. Look at the stickers. Put your own label on if you really can't remember.

But there is no excuse for not knowing how to lay down a motor. It's a substantial investment and needs looking after.
People waffle on about flag etiquette and anchors endlessly but seem to come over all Luddite when it comes to looking after an engine.
 
My 8HP Tohatsu 4-Stroke has not had any problems and I have it tilted at 50 plus degrees on the bracket when not in use. It also has to put up with me getting blown over to 60 plus degrees in gusts either side as well (lightly ballasted lake sailer in strong winds). I think you would have to get it laying down on the wrong side to at least 70 degrees before oil starts going where it shouldn't. As it is not an outboard with a handle, being one designed for remotes, handle up or down is not even a consideration. Neither is removing it anyway during the season as it is through bolted and locked to the bracket. Weighing in at 49Kgs means there is no way I am going to attempt to lift it in the normal course of events.

It is obvious on mine which way it should go as it has feet on one side of the housing and a big sticker saying which way it should go. I must admit I did have 6HP Suzuki (with handle) before that which was not so obvious. That one I did remove every time (different boat) and put down on the cabin floor when not sailing. That was borderline hernia country too. That actually was put on its back as there was not room to put it on its side. Never gave any problems.
 
Honda 6HP followed the manual and sticker on the side, laid it down in car correct side down, never had any problems!

Yamaha 6HP followed the manual and sti.............ditto bla, bla.

Store upright or raise the engine end up further whilst on it's side when stored if needed and you are worried about the boat rocking motion getting oil/water where it shouldn't. The manual says it should be stored up right on the transom and not lifted up on the catch as it may knock up and down on the catch in heavy weather I presume or when a MoBo goes by :D - just follow the instructions.
 
Unfortunately, the oil has to stay in the sump on the bottom of the engine on all 4 stroke engine whether big or small; this is one of the two basic differences between 2 and 4 stroke engines.

Engine designers will design the engine so that it can tolerate a certain degree of inclination and position without causing the oil to escape the sump; this is why there a limitation in the way it can be positioned side down.

Now, if a designer designs an engine with a removable sump then the sump can be "unscrewed" and removed, allowing the engine to laid down anyhow we want to, like a 2 stroke. That is a good idea!!!!;)
 
the downside

CAPTAIN FANTASTIC said:
Unfortunately, the oil has to stay in the sump on the bottom of the engine on all 4 stroke engine whether big or small; this is one of the two basic differences between 2 and 4 stroke engines.

Engine designers will design the engine so that it can tolerate a certain degree of inclination and position without causing the oil to escape the sump; this is why there a limitation in the way it can be positioned side down.

Now, if a designer designs an engine with a removable sump then the sump can be "unscrewed" and removed, allowing the engine to laid down anyhow we want to, like a 2 stroke. That is a good idea!!!!;)
Click to expand...

There must be some elegant way of desiging a four stroke so that it can be stored or even run at any angle.

The thing that amazes me is that they can standardise the side the tiller arm is on but not the way the engines are laid down

and.....

why is it always on the same side

I presume because most of us are right handed

maybe they should make left handed outboards

D
 
dylanwinter said:
There must be some elegant way of desiging a four stroke so that it can be stored or even run at any angle.


why is it (the tiller) always on the same side

I presume because most of us are right handed

maybe they should make left handed outboards

D
Click to expand...
Four strokes can be dry-sumped, but that is a very expensive and weighty answer to the problem of not learning which side to lay it down.

Your point about the "handing" of the tiller is a very good one. It should be possible as motors are made in large numbers and the internal connections to the motor are all by cable.
 
Lakesailor said:
Just a minute.
Have you (any of you, not aimed at any one in particular) noticed that most outboards (including 4 strokes) have two tilt settings so that you can leave the motor slightly tilted or at about 50°?
They are absolutely fine like that. My last motor and current motor don't object.
Even if you have steering swivel on, the tilt doesn't cause catastrophic and lasting damage.
If you know about engines you'll know that 2 strokes do not have a sump with a volume of oil at the bottom.
4 strokes do.
They also have valve gear and a camshaft to operate the valve gear. Normally the side that has the valve gear will have an open chamber through which the oil could run if laid on that side. One valve will normally be open at most points of the cycle so oil will have free access to the cylinder via that route. It only has to run down the oil stem. If you are really determined you could let the oil run back up the bores past the pistion rings. But that would take some definite effort.
As Niander says, each engine has it's own foibles and requirements which are laid out in the handbook and the usually on the motor itself.
If you can't be arsed to learn those requirements. More fool you.

If you prefer a stinky, fuel-hungry oil burner, just because you don't have to learn how to treat it. Fine.
Click to expand...
My Suzuki 2.5, must be laid on the handle. The opposite side of the crank case has a breather on it, open to a rubber pipe which goes to the air filter. So laying it wrong side down and the crankcase oil WILL flow out in to the air intake. Even laying it the right side up, going from home to the boat allows oil to pool around the bottom of the piston where it seeps past the rings and enough gets in the cylinder to hydraulic it! Embarrassing when you push off and havent started the engine, only cure is to remove the spark plug and whip it over a few times.
Stu
 
My honda can only be laid on one side and it has a flange to give a flat surface for that. All to do with valves, etc I believe. When fitted on the boat, it can be tilted up to nearly the horizontal with no problems. It is a 30hp though.
 
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