2020 DF250 SS Overheating

[Buckkoo]

I have a SeaFox CC236 powered by a DF250SS. I had been cruising Saturday at 4600 rpm for about 5-6 minutes when the Suzuki digital gauge gave an overheating alert and the engine powered down to idle. i maintained the idle for a few minutes, then returned to the dock at 3000 rpms. No issues.

My previous DF150 would run at WOT with no issues, not sure what would cause the new DF250SS to overheat. Any ideas?

[tsturm]

I have had a Bull Kelp leaf wrap around the lower & cause that same issue.??

[Buckkoo]

We don't have Bull Kelp on North Carolina lakes, but do encounter Hydrilla later in the Summer. It is possible that something temporarily blocked the water intake, so I may need to recreate the problem.

[Buckkoo]

Took the DF250 out again Saturday and within 10 minutes, it overheated again and no the the water intake was not blocked.

Suzuki digital gouge this time showed an engine code of 3-1, which points to the IAC or Idle Air Control. After idling 2-3 minutes, the engine resumed normal operation.

Garmin engine gauge shows water temp of 175

[artdf175]

how many hours on the engine ?
even though it is just a year old, the water pump may be failing
Art

[Moonlighter]

Lots of possibilities

Engine may be set too high and not getting clear flow to the pump

Pump impeller may have been damaged due to being run out of water or dredging sand

Thermostat might be stuck

Have to investigate these kinds of possibilities and see what you find.

[Buckkoo]

It is at the dealer for its 20 hour service and repair.

Turns out the Idle Air Control or IAC has tested bad and a replacement is on the way.

[Moonlighter]

It is at the dealer for its 20 hour service and repair.

Turns out the Idle Air Control or IAC has tested bad and a replacement is on the way.

Did they explain how this would cause an overheat?? Or even an overheat alarm??

It would be interesting for everyone to know for future reference!

[artdf175]

Like Moonlighter indicated- explain that one..
First off the IAC valve does not put the engine in safe mode - 3000 RPM...
It is there to control the idle speed and and the dash pot effect (i.e.- pulling the throttle back from, say, 4500 to neutral, and not kill the engine.
an extraordinary action based on what you have told us.
when you returned back to the dock at 3,000 rpm, would the engine run at a higher level? 3000 is the fail safe level of certain errors are detected.

art

[Buckkoo]

I'll have to ask the dealer, when I pick it up. Yes, after a couple of minutes, the engine ran as normal.

[Buckkoo]

Service Manager at Performance East is saying that IAC is stuck open causing air/fuel mix that at 4500 causes overheating...

in any event, they should replace IAC next week and then retest.

[redlowrey]

This is an interesting one, in your first post you say you are cruising at 4500rpm,the over heat alarm comes on and the engine drops back to idle, if the iac valve was stuck open how would the engine idle it would be sitting on 1400 or more rpm.

Second bit of confusion, these engines run a map sensor, the air fuel ratio is calculated from engine load ( pressure difference inside the inlet manifold ) would make no difference at what position the iac valve was.
If the engine was running a MAF air flow sensor and had an air leak in the system the engine would run lean because it needs to measure the in coming air before it goes through the throttle plate.


You wouldn’t think that there would be much wrong with a new engine, with the iac valve stuck open you would have noticed the high rpm at idle.

I think what has happened,when the engine went into over heat, because your engine has a throttle cable, with the throttle open, the only way that the computer can drop the rpm is by turning off spark and injectors.
This is why I think the iac valve threw a code trying to control the idle, putting the shifter into neutral it will reset straight away.

[Buckkoo]

So your thinking water pump or impeller, seems like there would be a code for insufficient coolant flow to cover this circumstance

[Moonlighter]

There isnt a code for water flow, but there are 2 temp codes...

Temp absolute, which is when the engine reaches a preset temperature (too hot)

Temp gradient, which is when the engine temp increases too rapidly but has not reached the temp absolute level.

The overheat codes are stored on the ecu so when hooked up to the SDS computer, the overheat events your engine experienced will be identified as one or the other. Which should give some clues as to why they happened.

I am with Red on this one, I think that changing the IAC valve is probably treating the symptom, and not the root cause. I guess we shall see....

[redlowrey]

Start with checking the thermostat they’re designed to fail open it may not be opening far enough