Outboard hassles

[jwalker]

Originally Posted by brucehawsker

Do you mean take out the brass screw all together?

Yup.

[Jackwabbit]

What JW said is spot on, the 2 ½ to 3 turns out on the mixture screw (the one with a spring behind in the side of the carb) is always a good starting point on all engines 2stroke & 4stroke.
We have had this slow running problem a lot with Auto-lube two stroke engines, especially after leaving them unused for a time.
It has always been the same thing, blocked slow running jets within the carbs.
Is your engine still under warranty?
If so why not take it back to let them sort it out, if its outside the warranty period it looks like you are going to have to take the carb off and clean it out.

[jwalker]

Sorry Jackwabbit but, from what Bruce has said, it seems, in this case, the one with the spring around it is the tickover adjustment and the mixture screw is inside a hole.

[Jackwabbit]

oops OK so they keep changing things but it still sounds like slow running jet or hole or whatever they have put in this time.
Whatever it is I hope you get it sorted soon.

[brucehawsker]

Thank you for all your help. Called Suzuki dealer this am. They confirmed it was the slow running hole which was blocked. Need to take carb off in their view. Offered to do it under warranty when I am passing Lymington tomorrow so bit off his arm. Said he'd show me how to do it.

It is great you all arrived at the corrrect dianosis - sorry that I am too much of a wimp to try and sort it myself - I am getting out of my DIY level of competance!

Cheers

Bruce

[roohairy]

Idle jets blocking up can often be caused by leaving fuel in carbs when you store an engine, IMHO if you're not going to use it for a week drain the carb either by disconnecting the fuel line and running all the fuel through the engine (give it full choke as it starts to falter) or if you are lucky enough not to have a Johnson use the drain screw! This has cured 'faults' in several engines and is well worth while as a matter of course.

[jwalker]

Originally Posted by brucehawsker

They confirmed it was the slow running hole which was blocked. ...........- sorry that I am too much of a wimp to try and sort it myself

I'm kinda sorry you didn't do it yourself. You missed out on the satisfaction it brings. Next time...

[jwalker]

I thought I would just add a wee bit about outboards and carbs while we're on the topic.

Carburetters do not normally flow only fuel through their internal passages. The main system will have a jet, often referred to as the 'air corrector' which feeds air into the top of an emulsion tube. The main jet feeds fuel into the bottom of the emulsion tube. The air and fuel mix and it is this emulsion which isssues from the main nozzle as fuel.

The slow run system is normally similar. Additionally, at tick-over, air is added to the mixture via the progression holes which are on the atmospheric side of the throttle butterfly. As the butterfly opens, the progression holes are gradually subjected to inlet tract depression and they begin to flow some of the emulsion and so provide extra fuel during throttle opening. As the butterfly gets close to leaving the final progression hole, the main system should begin to splutter fuel and then begin to supply the whole of the engine's fuel requirement. This transition can be a problem area and it is a good reason for ensuring the fuel chamber float level is correct.

This emulsion air will usually be drawn into the front of the carb via the airbox and herein lies a problem. Outboard motors do not usually filter the inlet air so any bits of bugs, leaves, seagull wings etc. are able to enter the small fuel passages inside the carb. Plainly, this makes outboard motors more suseptible than road vehicle engines to dirt contamination problems.

There will also be a fuel enrichment device but we'll leave that for another time.

Here endeth the wee bit of gospel.

I just thought it might be useful to someone.

[brucehawsker]

You was right. It was the slow running whatever that was blocked. Now runs fine. How important is it to run the engine out of fuel each time? I use mine every three to four weeks. But it takes a lot of pulling to get fuel back into the carb if I run it dry. Hence decididing to leave petrol in while stroing in the garage.

What are your thoughts?

Thanks

Bruce

[jwalker]

Originally Posted by brucehawsker

You was right. It was the slow running whatever that was blocked. Now runs fine. How important is it to run the engine out of fuel each time? I use mine every three to four weeks. But it takes a lot of pulling to get fuel back into the carb if I run it dry. Hence decididing to leave petrol in while stroing in the garage.

What are your thoughts?

Thanks

Bruce

Phew, I'm pleased to hear that. Distance engineering is tricky!
----

Doesn't pumping the squeeze bulb fill the carb?

I've never found any difference either way. Some folk swear by one or the other. I'd just flush it out, wrinse it down and put it away. Give it a scoosh of grease occasionally.

[Phil Davies]

Originally Posted by brucehawsker

How important is it to run the engine out of fuel each time? I use mine every three to four weeks. But it takes a lot of pulling to get fuel back into the carb if I run it dry.

I have a similar problem with my Yamaha 4hp 4-stroke, which incidentally has an integral tank. Due to the siting of the carburettor so far from the fuel outlet on the tank, it regularly takes up to 10 pulls of the starter cord to draw the fuel into the carb and fire the bitch up. I always run the carb dry after each usage and therefore have to put up with this problem, but I find it preferable to having petrol leaking out of the float chamber after I chuck it in the back of the car and asphixiating the occupants, which is what happens if you don't run it dry!

As JWalker says, the problem should be resolved in your case by pumping the fuel bulb to fill the carb before you pull the starter cord. I don't use a separate tank so I don't have that option.

The issue of stale fuel is interesting. Apparently normal unleaded goes off after 1-2 months, although I once left half a tank of fuel in my Yamaha for 10 months and it still fired up and ran fine when I came to use it. I did, however, top it up with fresh fuel which probably helped.

[brucehawsker]

Originally Posted by jwalker

Doesn't pumping the squeeze bulb fill the carb?

No, not really. Still requires a worrying (have I flooded the carb again?) ten or so pulls

[Sharky]

If you have checked everything, it may be the idle jet in the carb which has got blocked. If you run it in water it must be above the cavertaion plate. Hope this helps!!!

[roohairy]

Fuel goes off faster in hotter temperatures, after a couple of months in cans at 40degrees it won't burn any more. Hopefully (unfortunately?) this problem will not affect most British users! The other thing for those of us stuck with old 2 strokes is that petrol breaks down the oil so the lubricating properties are reduced, hence the warnings about 'old' fuel. Should have said earlier that running the engines dry only really applies to 2 strokes that will not be used for say over a month, sorry!

[Colin F]

............... i can't claim credit for this but, we had the same hassles getting fuel through on our sib engine - yam malta.

Fill fuel tank with petrol tap closed, replace cap and close beather. Then shake engine to create a bit of pressure in the tank. now open tap first. the pressure pushes fuel through to carb. works well in my experience and doesn't seem to have any adverse affects

we're replacing this with a mariner 8hp as an aux for the ribcraft as it's a lot heavier than the little avon we had before. it is also the max our sib can take

[Phil Davies]

Originally Posted by ribnwheels

Then shake engine......

Not sure about shaking a 4-stroke with all that sump oil slopping about. You can't throw small 4-strokes around with quite the same abandon as 2-strokes, because the oil gets into the top of the cylinder, soaks the spark plug and then you've really got a starting problem on your hands. In fact if I'd known how temperamental small 4-strokes can be, I'd have bought a 2-stroke. Furthermore, the pro 4-stroke argument about noise levels is largely irrelevant on this size of outboard and about the only thing I can say in its favour is that I don't have to pre-mix the fuel.

[Colin F]

Originally Posted by Phil Davies

Not sure about shaking a 4-stroke with all that sump oil slopping about. You can't throw small 4-strokes around with quite the same abandon as 2-strokes, because the oil gets into the top of the cylinder, soaks the spark plug and then you've really got a starting problem on your hands. In fact if I'd known how temperamental small 4-strokes can be, I'd have bought a 2-stroke. Furthermore, the pro 4-stroke argument about noise levels is largely irrelevant on this size of outboard and about the only thing I can say in its favour is that I don't have to pre-mix the fuel.

agree phil, mine is a 2 stroke. i would only have them as an aux engine purely because i know one day i would lie it down the wrong side and lose the sump oil..............bound the be the day you really needed it.

in terms of shaking it around, all i do is flick the engine left and right a couple of times within its steering range. i wouldn't imagine it would slop the smp oil around, but it is enough to stir the fuel

[tue]

Its so not much the fuel "going off" as it is the oil separating and gungeing up that causes the problems with 2stroke outboards. With a four stroke you shouldn't really have any problems with stale fuel (you must have left your car for few weeks In an airport carpark and then gone back and started it fine without first having run it out of fuel? ). The problem with the integral tanks tends to be dirt deposits being added to the fuel tank from the filler can. Avoid using metal Jerry cans as rust particles can fall into the tanks.