Water in lower unit ? - Page 2

HighlandR · 01 August 2014, 15:41

Peter, are you 100% sure that this engine should have a continuous flow of tell tail water ? I was led to believe the thermostat opened and closed when needed.

The starter motor does not turn at all, no noise, nothing. I'll hammer it and see if it turns, if not i'll check the ground wire

Peter_C · 01 August 2014, 17:06

Quote:

Originally Posted by HighlandR

Peter, are you 100% sure that this engine should have a continuous flow of tell tail water ? I was led to believe the thermostat opened and closed when needed.

The starter motor does not turn at all, no noise, nothing. I'll hammer it and see if it turns, if not i'll check the ground wire

The tell tale is there to let you know that the impeller is pumping water. It should always be flowing water as long as the engine is running. It is very common that they plug. As in really really common to plug. You can blow it out with air, or try a piece of wire or something shoved into the hole.

Without water flowing from the tell tale doesn't mean it is going to hurt anything, it is there only to let you know the motor is properly pumping water. To me it is important to be able to look back and see my motor is pumping water. There have been a couple of times, kelp has wrapped around the lower leg and blocked water flow.

As to the starter you probably should try manually turning it a little bit to free it up and break any corrosion built up on the brushes.

jyasaki · 01 August 2014, 18:11

Thermostat, as far as I know is only closed when first starting from cold, so "as needed" is kind of misleading.

My Honda 40 was prone to plugging the telltale; I used a high pressure water jet on the outlet to clear it (actually got in the habit of hitting it every time I flushed the motor.)

jky

HighlandR · 02 August 2014, 12:37

Hi guys, just started the engine again from cold and it pumped water from the outlet for a few seconds then stopped - which it wouldn't do if it was blocked with dirt ?

Can anyone confirm if this is normal for this model of engine to have the tell tail water stop and start ? as I don't want to risk damage to the engine

jyasaki · 02 August 2014, 17:14

Are you running in the water? In a tank? or on a hose with muffs? (Or some other way)?

Pretty common for a hose to supply insufficient pressure to completely fill the water need, so you may not get a telltale.

If you've got the LU submerged, you should have at least some telltale stream at all times (weaker at idle, stronger when throttled up.)

I've never heard of an OB that shut off cooling water at any time (well, not one that continued running, anyway.)

jky

HighlandR · 02 August 2014, 17:25

Hi Jky, it's in a tank with the leg submerged, the intake is at least 12 inch depth

paddlers · 02 August 2014, 17:27

My experience is a bit limited but on my 2005 Mercury 15 two stroke I was warned to expect an intermittent flow due to the thermostat but strangely on my new Tohatsu 20 (4 stroke) and my 90's 135 Mariner the stream seems constant !!!

Have you had the thermostat out ? I replaced both mine on the 135 as one was not opening at all & the flow was brilliant after that.

HighlandR · 02 August 2014, 17:41

Paddlers, how often did the flow start and stop ? from cold start it flows for a few seconds then stops, it has ran around 2 mins with no further flow, so i switched off !

paddlers · 02 August 2014, 19:29

I'd have a poke around. Strimmer cord is good to poke up the outlet. I'd whip the thermostat out personally just for peace of mind!

Boatnomad · 02 August 2014, 20:36

Have owned a Yamaha 5hp and water always came out of the tell-tail.
Odd time had to put wire up to clear it and then it was fine.

HighlandR · 03 August 2014, 14:04

I used the hose to flush backwards through the system for a good 10 mins, water comes out fine from the exhaust port on each side and from the intake on the underside of the cav plate, if it doesn't pump itself now I'll take the thermostat out and have a poke around !

Landlockedpirate · 03 August 2014, 14:25

A number of the twin cylinder, 2 stroke Mercury transportable outboards DO NOT HAVE a continuous flow of water, it starts and stops as cooling is needed. This includes the 8, 9.9 and 15hp engines with the destinctive triangular head.

We had a 1998 Mercury 8hp on my dads old sailing boat, tell tail ran 50% of the time depending on how hard it was working and the water/air temperature.

As far as I know, this these are the only engines with intermittent flow.

HighlandR · 03 August 2014, 14:58

AAhhhh !!! Landlockedpirate, thanks very much for that, 2 other people had told me the same thing, and 6 others have said otherwise !

Since the water flows out when first started I've been under the impression the hoses etc are not blocked, so hopefully the thing is actually working as it should ! To be sure - How long can the motor be ran safely before switching off ? So that i can wait for water to pump out !

Landlockedpirate · 03 August 2014, 15:08

Just stick it in the test tank and run it till it stops, or pumps more water. In my experience, a 2 stroke siezing due to heat, isnt the end of the world. It will usually run again once it cools down.

But if its pumping at the start, it isnt blocked and remember most of the cooling goes through the leg, the water stream is only a tell tail and does little or no cooling itself.

Peter_C · 04 August 2014, 06:15

When the engine is cold the thermostat will be closed. So if the tell tale works cold, when you first start it, then it doesn't turn on or off by the thermostat.

Mostly likely there is a free floating piece of debris that gets in the way occasionally. Have you tried pushing a wire or string trimmer line into the hole yet?

Jizm · 04 August 2014, 18:26

Quote:

Originally Posted by Landlockedpirate

A number of the twin cylinder, 2 stroke Mercury transportable outboards DO NOT HAVE a continuous flow of water, it starts and stops as cooling is needed. This includes the 8, 9.9 and 15hp engines with the destinctive triangular head.

We had a 1998 Mercury 8hp on my dads old sailing boat, tell tail ran 50% of the time depending on how hard it was working and the water/air temperature.

As far as I know, this these are the only engines with intermittent flow.

Not heard of that, hey ho learn something new everyday....

Boats&Outboards · 04 August 2014, 18:49

Yes your model pumps when it needs, NOT a constant flow. It'll start to pump very hot, then stop as it cools.

To check the impeller is working, remove the stat (2 x 10mm bolts, however leave the rubber seal in place, or it will leak) and run it in a test tank. You'll get a strong, constant flow. Then test the stat, re-fit and run engine.

Some prefer a constant flow, so they remove the stat. You'll run into problems long term if you do this as its designed to run at the right temp, which gives best fuel, performance etc. Some refit a restrictor to slow the glow, giving a constant flow at the right temp.

This model never blocks on the tell-tale, as the outlet is huge!

Peter @ Boatsandoutboards4sale
07930 421007
www.BoatsandOutboards4Sale.co.uk

jyasaki · 05 August 2014, 00:59

Thanks B&O; I'd never heard of that.

jky

paddlers · 05 August 2014, 06:12

Peter primed me with what to expect with my 15hp Mercury & was spot on.

Top man

dpround · 05 August 2014, 11:59

I had a Mariner 25 that also had a thermostat on the tell tale so that water might not come out either because the engine was cold or bust... Stupid idea!

If in doubt, pull the cover off and keep an eye on the temperature of block by touching it carefully - or use infrared thermometer.

All the best

David