Susuki DT55 Low water pressure

[oaseeker]

Mt DT55 had low water pressure & a weak tell-tale. I replaced my water pump impeller. The clutch shaft jumped out of place so I had to pay to have the crank case opened and the shaft put back. The propeller shaft housing was frozen and had to be replaced. I just got the boat back and 300.00 later, I still have the same problem. What else can it be.
This all started when I last took her out and she couldn't get on a plane. I can't get up enough speed.

[Orville]

If you mean the engine is in rev-limit because of apparent low water pressure but idles ok then I would check the waterflow float switch.
I had a problem with one on a DT85 which actually made the whole multifunction display unit stop working for some reason!!!
Orve

[Steve.N]

I have exactly the same motor and same problem.

The motor would be ok for a while then cut back to 4000rpm (some sort of guardian mode I assume!).
I replaced the impellor the other week and then found the Tell-tale pipe was completely blocked - I unblocked the pipe and cleaned though all the water passages I could access, I was sure the issue was fixed so took her out for a run - she worked fine at first with a strong tell-tale but after 1hr or so she did the usual and cut back to 4000rpm (tell tale dissapeared after 10mins or so).
In frustration I took her into a so called Marine Engineer, it cost €200 to be told that she's fine, they only found some gunge in the oil flow sensor.
I replaced this yesterday (just incase), but I'm convinced it's a water flow problem. Why is my tell tale clogging with crap all the time?

Good idea about the water float sensor - how easy is it to access and fix?

Any help would be much appreciated as it's now driving me mad!

[Orville]

Mine happened on a DT85 and the sensor is easily accessible on the top/back of the powerhead near the spark plugs.

What actual alarm sounds on the multifunction display? If the oil then it could well be a gunked up oil-flow sensor..........

Best of Luck anyway.

Orve.

[Downhilldai]

Originally Posted by Steve.N

....The motor would be ok for a while then cut back to 4000rpm...
...after 1hr or so she did the usual and cut back to 4000rpm (tell tale dissapeared after 10mins or so).
.... they only found some gunge in the oil flow sensor.
I replaced this yesterday (just incase), but I'm convinced it's a water flow problem.

It could be oil flow, oil level, water level, water temp, or exceeding max RPM

Originally Posted by Steve.N

Why is my tell tale clogging with crap all the time?

Soozooks are notorious for blocking tell tales. It is only a tell tale though and won't in itself switch the motor into guardian mode if it's blocked. The float switch in the cylinder head does this.

Originally Posted by Steve.N

Good idea about the water float sensor - how easy is it to access and fix?

Two screws and an electrical plug. When you take it out, check inside the water jacket for any salty deposits.


As Orville asked, which warning light(s) shows on the monitor gauge when it goes into guardian mode?

[Steve.N]

I know oaseeker mentioned at the start of the thread that he had an alarm but I don't get any, the engine just cuts back to 4000rpm out of the blue - no warnings, buzzers or anything.

I'm very careful not to over-rev the motor - She's always kept between the 5000-5500rpm (peak power-band), the last twice she cut back to guardian mode was when I had been at displacement speed for a while before powering up to cruising speed - she would power-up then cut back after approx 30secs - Very strange I thought??

Salt deposits makes sense as the previous owner used her on saltwater only, but he assured me she was flushed after each use - going buy the condition of the rib and motor I'd say he wasn't lying. Would deposits still build up through time even if he was flushing it with the muffs??

Would salt deposits around the thermostat cause any of these problems?

[Downhilldai]

Do your warning lights and buzzer come on when you first switch on the ignition, before starting the motor?

[Steve.N]

The buzzer doesn't come on, but the warning lights do before the motor starts up - they go out as normal when the engine starts.

They all work though as I tested them a few weeks ago.

[Downhilldai]

Sounds like your buzzer's defective, as this should come on when any of the warning lights are triggered.

If all the warning systems and lights are working ok, then something else must be causing it to go into guardian mode. It doesn't appear to be over-rev and you've already looked at the oil flow, so I'd be looking at the oil level and water temp/float switches. These should in any case trigger the warning light.

Has the motor always done this, or has it happened since something has been changed or altered?

[ribdraft]

glad to know i'm not alone??