New member, water flow pilot hole problem

[KiwiPom]

Hey all,
My mid 90s DT55 has a cooling problem I need some advice on.

When cold and on ear muffs I get a reasonable flow of water from the pilot (pee) hole, but as the motor warms up further the flow slows to a dribble, then finally seems to cease altogether. Water continues to come out of the mid level discharge hole, and when running if I put my hand in it seems warm but not hot. I've just replaced the impeller so I can rule that out. What could be causing this? And should I stop running the motor until I have discovered what is wrong?

Not sure if it's related, but I get a beep on engine start, and then another beep a few seconds after start. Not sure what this means, can anyone shed some light on this? I've only recently bought the motor so don't know what any of this means...
Thanks for your help!
Jason

[Solarman]

dt55, mid 90's, cooling problem

Have you got good water pressure on the muffs? Have you tried the motor when down in the water, not on muffs? Sometimes low water pressure on muffs can do this. Does your monitor gauge indicate/ flash the temp light? Did you get a repair manual with the motor?
Let us know.

[KiwiPom]

The muffs seem to have good pressure. and the water was flowing fine. About ten minutes after I got out on the water though the flow started to decrease until it finally stopped. There was still plenty of water coming out of the mid leg exhaust though and no overheat alarm.
Brought the boat back home, put it back on the muffs, and water flowed again, but only for 5 minutes, then started to decrease again.

[Solarman]

dt55, mid 90's, cooling problems

It sounds like your thermostat is opening to far? Do you have the shop/ repair manual? If yes, look to see if you have a bypass valve in the cooling passages? I think my motors do, ill look at my book tomorrow.

[38 Angler]

Waterflow, --- pilot-hole problem

Since you replaced the impeller already (I assume you installed it correctly) the problem might be caused by debris in the cooling-system . On account of water being expelled through the other hole I would believe that the thermostat operates . --- Try to poke a needle or thin wire into the pilot-hole and see what happens . --- Over the course of the decades I'd experienced similar problems a few times after negotiating shallow , silty stretches . --- Generally , after some poking and high-speed-operation the dirt was flushed out and everything went back to NORMAL again .

[KiwiPom]

Thanks guys,
it was low tide when I last went out and I did stir up a lot of silt. I've already tried the piece of wire trick but it did nothing. Next step is to disconnect the outlet tube so I can get a better poke around in there and see if that helps at all. I've also been considering using one of the descaling products such as Rydlyme; has anyone had any experience of these?
I don't have an owners manual or workshop manual for my model, but I have managed to download the generic service manual that covers most of the Suzukis. The diagram for the inline models is highly ambiguous: The picture seems to indicate that the pilot (pee) hole is the last stage before the exhaust, after the water has been round the cylinder head; but the flow diagram shows it as being before the cylinder head. I'm not entirely sure if this is relevant, as the water does seem to be coming out of the mid leg exhaust (described as the water overflow outlet in the manual).
I've also read several comments in other forums as well as this one that outboard technicians have been known to tell customers not to worry about the pee hole, that it's mainly for show.
I guess my bottom line is.... can I continue to take trips in the boat or should I not use it until I get to the bottom of the problem?
Thanks again, and excuse the rambling post... I'm a bit new to all of this.

[Solarman]

dt55, mid 90's, cooling problem

Ok Jason, on the inline cylinder system (yours and my motor design), there is a pressure check valve (spring & ball style), mine is located at the base of my water jacket under the cylinder head cover plate. Yours may be in the same area. If it is stuck open then when the motor is cold, there is enough pressure for the pee hole to operate. If stuck open, and thermostat opens, then it's probable the pee hole will stop, because all the water is flowing back to the discharge hole, and thermostat passage.

I would try the flush you mentioned (rydlyme) to clean the passages of corrosion. If that doesn't free up that check valve, it may require removal of the water jacket cover to clean it manually. If so, you should get a shop manual before attempting. Because you need to know exactly where yours is located first. Also, a soft tapping on the cover where it is located after running the flush through for the time needed, while still flushing, may dislodge it before opening it up? Do not hammer hard on cover plate, it is aluminum.

After flushing, you can also try running it at full throttle in the river, to see if the extra water flow causes it to start working.

good luck let us know how it goes.

[KiwiPom]

Thanks again. Just need to find a local distributor for Rydlyme here in NZ then I'll get on to it.
In the meantime, any idea where I can get a copy of the service and/or owners manual for the DT55?

[Moonlighter]

I have also seen quite extensive reports on The Hull Truth about people using a vinegar solution to clean out outboard engine galleries. Apparently with good success.

Here is a link to "how to".

How to: Cleaning your cooling system with vinegar - The Hull Truth - Boating and Fishing Forum

[KiwiPom]

***, interesting reading! I'm up to page 6 and fascinated. Seems vinegar may be the way to go. I'm going to set up a pump system so I can pump it through for a few hours without running the motor.

[KiwiPom]

Hey Solarman,
does every outboard have the pressure check valve? Can't seem to find any reference to it in the service manual...

[Solarman]

dt55, pee hole flow

Ill have to look my pressure valve up and click on it to see if used on your motor. ill get back after checking.

[dj_movers]

My DT 115 has a Pressure Check Valve. It is discussed in the "General Information" section of the Service Manual.

By the way, I am having a similar problem as Kiwi. Impeller was just changed at shop. I will post back and let you know what I find on mine. Good luck!

[artdf175]

Thanks again. Just need to find a local distributor for Rydlyme here in NZ then I'll get on to it.
In the meantime, any idea where I can get a copy of the service and/or owners manual for the DT55?

I would check out brownspoint . com for your manual
that is where I ordered mine from -seemed to me they had the best prices

----also.. have you tried a small wire up the pee tube when the motor is actually running & when the flow slows down...
it could possibly help clear any debris
just a thought

[KiwiPom]

Managed to get a service manual on another forum, and have also found a distributor in NZ for Rydlyme, so I'm almost set. Thanks again Solarman, appreciate your help.
Dj I've read that there are a couple of grommet seals at the top and bottom of the water pickup tube that may leak and stop the water being pumped properly. I've also read that the exhaust can somehow leak back into the water channels (corrosion hole I guess) which would also stop the flow.
With mine it strange that the flow seems to cut off very gradually over about a 15 minute period when out on the water, as though someone is slowly turning a tap off. Not at all like the way a thermostat operates.
I'm hoping that it's just built up crud and scale in the system...