DF50 2009 - pee-hole output intermittent and sometimes stops

[Murray]

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[mike.floutier]

Thanks Murray, that's awesome, although mine is clearly very different you've given me a great idea of where to look, ie the later model df50 manual.

By the way, in researching cooling, I came across the brilliant YouTube channel - https://youtu.be/joEQChcZl2A . It's not Suzuki specific but it's so helpful and beautifully presented.

[mike.floutier]

image.jpeg Ok, finally tracked down the Water Pressure Valve. The image page is here - https://goo.gl/images/4Kyyib - and I've attached an image as well for future reference.

Since I don't really fancy the required level of dismantling just to examine the valve, and, since the problem would probably relate to it sticking open due to gunk, I'll rely on it being restored to normal operation by virtue of my intended vinegar cleaning regime.

At least I don't have to waste any more time searching for it and the mysterious manual chapter 7.

Will report back next week when I've done the cleaning and refitting of lower leg and new thermostat.

Thanks again Murray, you encouraged me to continue searching. You can see why they shifted it to be an external fitting on the "a" models,, it must be a common problem.

[mike.floutier]

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Thanks for your comments guys....

4. The total "dribble" when you combine both dribbles (the two pics) PLUS another small amount leaking from the bottom of the lower engine cover is fairly significant.

TxAg66 asks if the dribble is normal. The diagram of the water cooling system is particularly helpful in this regard. It's clear that, FAILING any leaks caused by punctured pipes or poorly fitted joints etc, water should ONLY exit through a) the pee hole, b) the Prop exhaust outlet, and, in undesirable circumstances, through c) the Pressure Valve.

Many thanks! Mike

Just going back to this aspect, ie the water flowing from the (designed) holes in the front of the mid unit, it now makes sense (since we now know the Pressure Valve is internal) that these (two) holes are there to let out any water that passes through the Pressure Valve.

Does this his make Sense?

The purpose of the pressure valve, as I understand it, is to reduce the pressure created by the impeller when operating at higher speeds (which would otherwise over-cool the engine).

The fact that water comes out here at lower speeds seems to indicate that the pressure valve is sticking partly open. Although I can't see it, I'm guessing it's in a similar condition to the thermostat which itself was found to be blocked in a slightly open position by gunk (which was easily washed off)

[Hoosmatroos]

No that is not the case. Most of the water comes out internal. The pee hole drops only a small portion of the water. The engine can't be over cooled as long as your thermostat is working. The thermostat closes when the temperature drop beneath a specific value. Then the engine warms up and the thermostat opens again. It's true that it reduces the pressure as this becomes too high.

If the valve is stuck open then there is little water pressure to the engine and so not enough cooling.

[Murray]

When looking for vinegar check out pickling vinegar, it’s 7% acidic acid as opposed to 5% table vinegar.

[mike.floutier]

Thanks Hoosmatroos, I guess my main question was: "where is the water in the picture coming from?" My guess at the answer was: "output from Pressure Valve". Is that correct do you think?

Thanks re the vinegar Murray, only trouble is that pickling vinegar locally is about 6 times the cost of table vinegar; I'll just use a stronger concentration

[mike.floutier]

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Ok the weather here is awful so no chance to visit the boat to work on the motor so just doing more research on the whole cooling process for the DF50.

The attached picture shows top view of the lower unit. Although it's not my exact model you can clearly see the water hole in the front top flange that equates to my earlier pic showing water coming out.

It looks as though this hole (holes in my case), is a sort of "catch all" that lets out any water that accumulates in this area. Seems odd since I'm guessing that the big square hole in the back section, in the pic, is presumably the exhaust channel and I would have thought that all local water would naturally pass down here.

On the other hand I guess there may be a pressure issue here, in that the exhaust opening is submerged AND gas pressure from the exhaust plus cooling water pressure (all this at high revs) may need the relief provided by this hole to protect the gearbox oil seals from water ingress.

Just trying to think it through eg perhaps it's reasonable to expect water from these little holes at the top front of the lower unit most of the time?

[Hoosmatroos]

When you tilt the engine then the water can leave the inside to prevent buildup inside. Don't know if they where designed for something else.

[Murray]

When you tilt the engine then the water can leave the inside to prevent buildup inside. Don't know if they where designed for something else.

To my understanding the water pump(external) is flooded with water when lowered into water. When you lift the engine out of the water with the tilt or trailer then those holes are there to drain water out of the cavity. The water inside the water pump drains out via the water intake. Thats why you store the boat with the engine down during the winter, allowing water to drain out of the pump and the water that surrounds the pump.

[mike.floutier]

Thanks Guys, that does make sense.

I got a chance to visit the boat today and:

1. I removed the lower unit to check on my previous work, making sure eg. the water pipe was fitted correctly and to check on build up of deposits - there was quite a bit which I cleaned up. I also checked the impeller housing for imperfections, as suggested, but all looked ok.

Whist the lower unit was off I looked up the mid unit, from below, to see if I could see the fabled Water Pressure Valve. Sure enough it was just visible right at the top - see attached pic - it appeared to be closed ok and looked very clean which was encouraging since I didn't fancy the dismantling required to replace it. Upper middle of pic, out of focus)

2. I then removed the old thermostat - the attached picture compares the old and new thermostats. As you can see, the old one is blocked in the partly open position in spite of me cleaning it up as best I could.

I then ran the motor (without the thermostat) in a big bin of vinegar/water mixture (approx 3 to 1, 3 being the vinegar. I ran it for around 30 minutes, until the water got fairly hot (not too hot to put my hand in).

I was getting a fairly strong and steady flow at the pilot hole which was encouraging and there was quite a lot of debris in the bottom of the bin after this - see pic.

I've stored the vinegar mix (sans debris) ready for next visit and will keep at it.

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[mike.floutier]

Did my 4th vinegar run today, still with thermostat out. I'm still getting around a teaspoonful of sand grain like debris coming out each time so I'll keep on doing this for the next couple of months whilst it continues.

Problem with running without the thermostat is that the engine is running too cool for more of the time than designed. I took one of the spark plugs out today to check this and, sure enough, it was covered with a fair amount of oil, as predicted. Must remember to replace them before launching in April.

[Hoosmatroos]

When you flush it with circulating water (and vinegar) then the water should warm up gradually and so your engine. But that said, when you replace your plugs in the spring then you should be oke.

[mike.floutier]

Did my 5th flush. This was about half of what was at the bottom of the bin so I'm encouraged to continue. This time I ran it for longer, about 50 minutes. I was concerned about over-heating as the water in the bin gets hot pretty quickly as you mention Hoosmatroos.

Is there any way of knowing if the overheat sensor system is working ok? I'd like to run it for longer nice and hot to avoid the oiling up scenario but concerned about overheating.

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[Murray]

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Not the same engine so specs. might be different but the idea is the same.