Running outboard "Dry" out of water

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tsf

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Common knowledge is of course this is a big "no-no" for risk of damaging the water system impeller when running dry.

As a greenhorn I find this frustrating when wanting to test my outboard just before launching. The first time that you're really sure if your actually going fishing is after the gear case is submerged and you crank it up.

Is this impeller issue really still a factor on modern outboard engines in 2017? Why doesn't the impeller start up 10 secs after the engine? An engine can't overheat in 10 seconds can it? Turning the engine over prior to launching would be so useful for checking/safety purposes.
 
It is a simple mechanical connection. The more complexity the more likely it is to fail.

You can buy muffs that attach to the leg with water supplied by a hose.

You can run an outboard for a very short time out of water, but the impeller is running dry and will shred very rapidly.
 
tsf said:
Common knowledge is of course this is a big "no-no" for risk of damaging the water system impeller when running dry.

As a greenhorn I find this frustrating when wanting to test my outboard just before launching. The first time that you're really sure if your actually going fishing is after the gear case is submerged and you crank it up.

Is this impeller issue really still a factor on modern outboard engines in 2017? Why doesn't the impeller start up 10 secs after the engine? An engine can't overheat in 10 seconds can it? Turning the engine over prior to launching would be so useful for checking/safety purposes.
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The engine wont overheat but the impeller will!!
 
Start it in water before setting off to launch site. Then at least you'll know all is ok, or not, rather than thinking "great, it's started ok" and then set off only to find you're rapidly overheating cos you cooked the impeller. That would really spoil your day!
 
Its one of those things that you see so often at the boat ramp. Sometimes after the boats been taken out of the water, as if they are trying to shed the water from inside it. And the classic example is when people are selling their boat and start it up in their driveway to show it works. It always makes me feel like I should go and stop them, like when you see someone beating their dog. One of the reasons I try to buy new whenever possible
 
Humm it does seem to me that in this day and age where trips to the Moon are being envisaged and with all the research and stuff that the Out Board Manufacturers will not develop a superior compound for the impeller, that will enable dry starts

When I researced it some years ago I came to the conclusion that the Manufacturers rather an O/B was stripped and cleaned out after every use in Salt Water wuich just might suit them, but certainly not the users.

Perhaps there is scope for Private Enterprise to get involved and 'sort it out' for us ?
 
Capt Popeye said:
Humm it does seem to me that in this day and age where trips to the Moon are being envisaged and with all the research and stuff that the Out Board Manufacturers will not develop a superior compound for the impeller, that will enable dry starts

When I researced it some years ago I came to the conclusion that the Manufacturers rather an O/B was stripped and cleaned out after every use in Salt Water wuich just might suit them, but certainly not the users.

Perhaps there is scope for Private Enterprise to get involved and 'sort it out' for us ?
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They are used in water so it is unclear what problem you are seeking to solve!
 
If you have access to one, get a free old oil drum.. the most common failure is the filler cap or top rim so an outboard test barrel ought to be free. If you really cant source an oil drum then a water butt from a garden centre will do the job.
 
I used our red recycling wheelying bin. Perfect no mods. Need to take the empty cereal boxes out first though!
 
Get Ear muffs for the engine about £20 and work fine, Don't mess about with oil Drums and huge vessels full of water
 
snowbird30ds said:
My little tohatsu has a plug on the side and a hosetail in the toolkit for direct hose connection, takes a minute and it has all the water it wants.
If you are going to the effort of launching a boat checking the outboard is only a few minutes extra, I too don't see what your problem is.
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The wash connection may by pass the impellar. I don't think you are supposed to start the motor while rinsing, although I can't say specifically for Tohatsu
 
snowbird30ds said:
If you are going to the effort of launching a boat checking the outboard is only a few minutes extra, I too don't see what your problem is.
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Yes I sort of get this argument - and I check the outboard at home with muffs. But, because I'm new to this, it seems feasible that you could test the engine at home with muffs, then drive 50 miles to the coast over bumpy roads, during which time you could damage or dislodge something in the electrical or ignition system, or the battery starts to fade. Then you drop it in the water and it won't start.

Like you lot I probably won't give it a second thought after I've been boating for a few years. But the problem just had me scratching my head a little bit. After 100 years of outboard development, you can still turn a brand new 10 grand motor to scrap by accidentally turning the key?
 
tsf said:
Yes I sort of get this argument - and I check the outboard at home with muffs. But, because I'm new to this, it seems feasible that you could test the engine at home with muffs, then drive 50 miles to the coast over bumpy roads, during which time you could damage or dislodge something in the electrical or ignition system, or the battery starts to fade. Then you drop it in the water and it won't start.

Like you lot I probably won't give it a second thought after I've been boating for a few years. But the problem just had me scratching my head a little bit. After 100 years of outboard development, you can still turn a brand new 10 grand motor to scrap by accidentally turning the key?
Click to expand...

There have been a small number of aircooled outboards, low hp, where you can run them to your hearts content out of the water. However the muffs that have been mentioned in this thread will come in handy to protect your ears from the noise. Just remember not to connect them to the water supply..........:D
 
BruceK said:
There are some manufacturers of impellers that claim to be able to run dry for short periods. I cant comment with no experience but here is an example
https://www.gcsmarine.com/content/impellers/impellers

I have heard in idle conversation the RNLI use a "non standard" run dry impeller, if true maybe someone can shed some light?
Click to expand...

Hi thank you for that good info, BruceK, will come in very useful.
 
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