Water Flow at Idle

Post here for issues with outboard engines (i.e Yamaha 9.9) on PDQ yachts
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thinwater
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Water Flow at Idle

Post by thinwater »

Is it normal to get a good flow at start-up, and then mostly just exhaust when idling? It seems when setting still the exhaust must rise up and get in the water inlet. The exaust is pumping through with just a little water.

I'm fooling with some new-to-me engines in a barrel of water. However, it occurs to me that one of the engines on the boat does the same thing and does not seem to overheat.
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Re: Water Flow at Idle

Post by Page 83 »

Follow the little hose around to where is comes out of the block and clear any obstructions. If the barrel isn't too big, add a lot of "salt away" and let it run to warm and stop it several times. If you are really worried about it, take it apart!
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The flow at start is full blast.

Post by thinwater »

Page 83 wrote:Follow the little hose around to where is comes out of the block and clear any obstructions. If the barrel isn't too big, add a lot of "salt away" and let it run to warm and stop it several times. If you are really worried about it, take it apart!
I did pull the lower unit and cleaned out the hoses.

So, what is with these lame Yamaha engines? I have now lived with 4 of them, and they all have the same problems, to varying degrees. Very disappointing. I had a Nissan 18 for 15 years; never changed an impeller, spark, flushed the engine, or looked at the carb. Started first push, every time. Same story with my prior 9.9 engine. Now it seems every Yamaha has carb troubles, charging problems, impellers needing replaced, and they clog. At only 10-12 years old we think they are toast. Yes, they have good reverse power, but there MUST be something much better. I have instructed my wife to beat me if I EVER go near a Yamaha for a replacement.
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Re: Water Flow at Idle

Post by Page 83 »

Necessity is the mother of invention! Go boldly where man has never gone, and snap up the franchise.
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Re: Water Flow at Idle

Post by amytom »

I've found that the little brass fittings coming out of the port side of the block are a big part of the problem. I would pull the thermostat and cover. Run the engine for a short time to ensure that water flows up and out of the open cover. Reinstall the thermostat (after testing in a pot of boiling water) and pull the top and bottom hoses off of the brass fittings. If water isn't flowing through one or both of them I would pull the brass fittings out of the block. The fittings are just pressed in but will likely be damaged as you pull them out. The part number is 676-11372-00 and can be had from http://www.boats.net .

You will probably find a wall of salt and corrosion behind the fittings. I used a small screwdriver to break this up and clean it out. Then hammer a new fitting in and test again. I found both of my engines had blockages in at least one of these tubes.

Good luck and let us know how it works out.


PS My engines are 98-99 series so please double check this with the boats.net website before ordering parts for your '00 engines.
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Re: Water Flow at Idle

Post by Allezcat »

Good luck with finding the blockage. I have two 03 models blocked up with no water out of those tubes. I took out the nipples. No salt blockage and no water flow. Probed into the hole with a wire but unable to find the blockage. I guess its teardown time! Has anyone taken off the exhaust plate cover to probe in that area?

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Re: Water Flow at Idle

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see Colin Swithenbank in a search on this site for "salt". Drill down to circa 2006. With more hard science than I can follow, he says household vinegar will deal with the problem, which is not salt but calcium carbonate. This is REALLY worth looking into.
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Re: Water Flow at Idle

Post by SecondWind »

Hey guys,

How about a pair of these with a diesel genset !

http://www.ecyclemarine.com/eCycleOutboard.html
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Re: Water Flow at Idle

Post by Page 83 »

I did consider them Terry since I already have a 5kw generator, but I would need a 10! That got way far away from my price range.

Another very interesting option is the latest Torqedo, which has the thrust of a 9hp outboard. I just spent a fruitless half hour trying to find a video I've seen recently of a 45' cat equipped with two of these.
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repowering w/ electric

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Re: Water Flow at Idle

Post by thinwater »

I did have one blocked below the impellor.

Take the lower unit off, turn it upside down, and blast with hose. Salt removing products are a good idea too, but this case was a wasp nest !
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