Why not turn outboard upside down?

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NickC

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Is there any reason why a 4-stroke (6hp Johnson/Suzuki) should not be turned upside down? Apart from possibly clamping the oil breather pipe closed or disconnecting it.

I would like to turn this upside down so that I can soak all the salt encrusted water channels in acid for a couple of hours.
 
Originally I always thought it was due to the oil getting to places it shouldn't, but speaking to someone recently I'm told it's more to prevent water getting to places it shouldn't, such as water trapped in the exhaust getting back to the cylinder.

I'm not sure which if either are the real reason, I just blindly do as I'm told so I don't find out.
 
maej said:
Originally I always thought it was due to the oil getting to places it shouldn't, but speaking to someone recently I'm told it's more to prevent water getting to places it shouldn't, such as water trapped in the exhaust getting back to the cylinder.

I'm not sure which if either are the real reason, I just blindly do as I'm told so I don't find out.
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So maybe I should take the spark plug out and make sure I turn her over a few times to clear out the cylinder before starting her up.
 
I think Id drain the oil to prevent that causing any unforeseen problems but as maej says you will have to be very careful not to get any acid cleaning solution into the cylinder via the exhaust.
 
VicS said:
I think Id drain the oil to prevent that causing any unforeseen problems but as maej says you will have to be very careful not to get any acid cleaning solution into the cylinder via the exhaust.
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I see your point, is there some way I can ensure that the engine is at TDC on the compression stroke before turning it over and putting the acid in.

Then again if the plug is out what harm if some does get into the cylinder bore, at best it is going to clean some of the coke of the rings. Once started any residue will soon burn away.
 
How noxious/corrosive is the stuff? Could you put it in the barrel and then run the o/b at tickover for an hour or so? That would have the advantage of warming it up and helping to dissolve deposits. alternatively have the gearbox off, put a bucket or basin under the o/b with it held upright(on a stand, or on a plank in a vice or workmate perhaps) and using a funnel and a bit of hose on to the pipe that takes the water from the water pump, pour it through the waterjacket; if you hold the funnel just above the powerhead it should just trickle through slowly.
 
Turning a 4st engine upside down and pouring acid into it is a really bad idea.

I would be very cautious on using ANY acid on aluminium even vinegar which is acetic acid.

Fresh water flush by running in a bucket however is a good idea as is using the giant nose clip style flushing accessory.

In the past I have resorted to dismantling and chiseling out such scale deposits. Very much a last resort.
 
NickC said:
I see your point, is there some way I can ensure that the engine is at TDC on the compression stroke before turning it over and putting the acid in.
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You could, but the odds are that the oil that flows into the rocker cover will fill up the holes that lead down to the top of the valve guides as you right it.

I'd prefer to have control of the acid with ref to the various metals that it may get to and so would take the head off. Nobbut a 41 yr old Chemistry O level, but I'd worry about any Copper in the gaskets disappearing rapidly.
 
penfold said:
How noxious/corrosive is the stuff? Could you put it in the barrel and then run the o/b at tickover for an hour or so? That would have the advantage of warming it up and helping to dissolve deposits. alternatively have the gearbox off, put a bucket or basin under the o/b with it held upright(on a stand, or on a plank in a vice or workmate perhaps) and using a funnel and a bit of hose on to the pipe that takes the water from the water pump, pour it through the waterjacket; if you hold the funnel just above the powerhead it should just trickle through slowly.
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Yes, I could run it in a bucket of the stuff but I don't know how well it will dissolve the deposits while flowing around the engine. Your idea of putting a pipe on the inlet tube with a funnel is interesting but still got the problem that it will drain both from the indicator jet and from the water outlet which is in the top of the leg and cannot, as far as I can see, be stopped up in any way.
 
As its a 4 stroke piece of junk the orientation is often critical but it dosn't matter which way up it is as you throw it in the skip.

(Should have bought a Seagull!):)

Robin
Pleiades of Birdham
MXWQ5
 
VicS said:
Whatever do you imagine he will be using to clean it ?
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He said acid. I assumed that it will be quite concentrated, and my almost now nothing knowledge of Chemistry tells me that some metals will more readily react with particular acids. So I'd be happier pickling only the bits I want to treat, and separately in a controlled manner.

I didn't add that a quick lapping of the valves while the head is off wouldn't be a bad idea.

But of all the members here Vic, you are one that I will be glad to be corrected by!
 
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NickC said:
Yes, I could run it in a bucket of the stuff but I don't know how well it will dissolve the deposits while flowing around the engine. Your idea of putting a pipe on the inlet tube with a funnel is interesting but still got the problem that it will drain both from the indicator jet and from the water outlet which is in the top of the leg and cannot, as far as I can see, be stopped up in any way.
Click to expand...

In that case it might be best to remove the powerhead, drain the oil, then invert it; that way you can be sure of where you're putting the descaler and avoid it inadvertently going in the exhaust port and thence the cylinder.
 
Used to have an old seagull.
you could turn it any which way you liked.
A spare plug was essential though they liked to oil up.
just change it clean the one you took out you will need it again soon.
 
DaveS said:
So, how did you do it then?
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He says,

Engine flushed over the weekend with that sulphamic acid. Took about 3-5 hrs of flushing / resting cycle as water indicator jet very gradually got slightly stronger and stronger. Unfortunately had to use a lot more water than expected so concentration was probably only half what I was aiming for but still seemed to work.

Took her out for a test run on the river on a small rib yesterday and had a very constant, reasonable but not heavy, flow from the indicator for all that time. I guess this is probably about as good as this engine is going to get.​
 
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