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Post by Deleted on Dec 28, 2018 20:25:57 GMT
www.canalworld.net/forums/index.php?/topic/99570-outboard-telltale-query/Tom, spiders have crawled up your tell tale and blocked it. Rod it out with a small drill bit. if it is not overheating you have no pump problem. Alan and Wotever are talking shit. the pump is driven in direction of rotation by the engine - it cares not whether it is in ahead or astern- forward only my arse - Twats! The gearbox is driven through the pump. it will pump water well in neutral at idle the Honda has a bypass in the leg and you should see some water and steam coming from here - the rest goes through the propeller hub to exhaust underwater.
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Post by phil70 on Dec 28, 2018 20:31:54 GMT
Exactly as Gazza says with the added proviso that tell tales can get bugged up a bit with very fine weed filaments. I used an outboard to get to and from work, shops, pub etc etc for 10 years.
I kept a bent paperclip for "rodding out"
Phil
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Post by Deleted on Dec 28, 2018 20:38:02 GMT
Exactly as Gazza says with the added proviso that tell tales can get bugged up a bit with very fine weed filaments. I used an outboard to get to and from work, shops, pub etc etc for 10 years. I kept a bent paperclip for "rodding out" Phil Hondas and yamahas are by far the worst culprits for this. I drilled the tell tale out on our yam 9.9’s - can’t remember what size, but just big enough to keep the spigot the hose pushes on to. That helped no end. Using them regularly helps too - as good an excuse as any - got to go out on the boat again to keep the pipes clear 👍🔨 |
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Post by tonyqj on Dec 28, 2018 20:47:30 GMT
So how come when my mate reversed the direction of rotation on the shaft on his ancient outboard leg the water started pumping? |
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Post by Deleted on Dec 28, 2018 20:50:59 GMT
Seagulls have a rigid plastic impeller which does not look to me like it would work backwards.
Eta it may be possible to get the engine to run backwards as its a two stroke. not sure if that's been done or not thus far.
They do it with Bollinger narrow boat engines so someone may have tried it.
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Post by Deleted on Dec 28, 2018 20:55:11 GMT
Also worth noting that whenever an outboard motor is running the drive shaft is turning and rotating the impeller. The propeller rotation direction is controlled in the lower unit using a dog clutch and gears.
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Post by Deleted on Dec 28, 2018 20:55:19 GMT
So how come when my mate reversed the direction of rotation on the shaft on his ancient outboard leg the water started pumping? Has he got a reversing engine rather than gearbox? It’s a load of old crap I’m afraid - duff info for someone without a clue. the pump is driven by the drive shaft from the engine to the gearbox in the lower casing - have a look here to understand how the box works. there is no special care neeeded when assembling impellers in outboard water pumps -they do not need bending to suit their DOR, they are flexible enough to take the form they need when first installed as long as there is a bit of lube/water present to ensure they do not start dry. |
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Post by tonyqj on Dec 28, 2018 20:58:27 GMT
So how come when my mate reversed the direction of rotation on the shaft on his ancient outboard leg the water started pumping? Has he got a reversing engine rather than gearbox? It’s a load of old crap I’m afraid - duff info for someone without a clue. the pump is driven by the drive shaft from the engine to the gearbox in the lower casing - have a look here to understand how the box works. there is no special care neeeded when assembling impellers in outboard water pumps -they do not need bending to suit their DOR, they are flexible enough to take the form they need when first installed as long as there is a bit of lube/water present to ensure they do not start dry. So he was simply driving the shaft in the opposite direction to the engine rotation I guess? Nothing to do with fwd/rev, simply that the engine turned the shaft anti-clockwise looking from the top? |
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Post by Deleted on Dec 28, 2018 21:12:20 GMT
Has he got a reversing engine rather than gearbox? It’s a load of old crap I’m afraid - duff info for someone without a clue. the pump is driven by the drive shaft from the engine to the gearbox in the lower casing - have a look here to understand how the box works. there is no special care neeeded when assembling impellers in outboard water pumps -they do not need bending to suit their DOR, they are flexible enough to take the form they need when first installed as long as there is a bit of lube/water present to ensure they do not start dry. So he was simply driving the shaft in the opposite direction to the engine rotation I guess? Nothing to do with fwd/rev, simply that the engine turned the shaft anti-clockwise looking from the top? Engine DOR is usually clockwise viewed from the flywheel When you overhaul a leg you bang the impeller in, clap it together, check it pumps - the pick up pipe can sometimes miss engaging with the grommet on the pump housing outlet, once water is confirmed to be circulating go and get a beer. I have no idea why you would bugger about trying to turn the pump by hand - the housing is a volute meaning it will only pump in one direction - the direction governed by engine DOR I use muffs as it saves pissing about with barrels/Whellie bins |
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Post by Deleted on Dec 28, 2018 21:18:04 GMT
Maybe its an electric outboard with the motor on top.
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Post by phil70 on Dec 28, 2018 22:14:39 GMT
Maybe its an electric outboard with the motor on top. Not sure that an electric outboard would need water cooling but hey you never know Phil |
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Post by Deleted on Dec 29, 2018 6:13:50 GMT
Maybe its an electric outboard with the motor on top. Not sure that an electric outboard would need water cooling but hey you never know Phil quite likely if the motor is on top. This one has a water cooled AC induction motor in the normal position is where the petrol unit would usually be. And probably water cooled power electronics as well.  www.aquawatt.at/GB/elektro_aussenbordmotoren_14_GB.htmlOn the other hand if the motor is a pod type it is cooled by the surrounding water like minn kota, motor guide and the other cheap trolling motors and some other more expensive units such as the torqueedo and Karvin. www.karvin.eu |
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Post by Deleted on Dec 29, 2018 11:13:53 GMT
tonyb surprises me - for someone who is regarded as an expert on cwdf and In the canal press in general he doesn’t half post some odd and not very useful info.
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Post by Deleted on Dec 29, 2018 11:33:59 GMT
I am now wondering if these electric outboards have the traditional dog clutch bevel gear arrangement or reverse the rotation of the motor itself.
The latter would be better but the former is probably cheaper. A generic outboard leg with the power head changed over.
In which case some sort of electric actuator would be required to enable fly by wire operation rather than a Morse type cable for gear change.
Quite interesting. I like electric boat stuff. A lot.
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Post by brummieboy on Dec 30, 2018 22:36:35 GMT
Long time since I had an outboard, but is it possible that in reverse, the leg could cavitate a very negative head to the intake, or even a void? That would create the situation he had.
Tony B generally speaks a lot of sense, but is inclined to contribute to situations he does not encounter; then again lots of people do that,(me included sometimes, but I hope not dogmatically)
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