Running hot. No overheat.

[Mike Pettee]

Can someone give me some info on what this symptom may lead too.

Starboard engine running a steady 10 degrees hot. Across the board but does not throw an overheat alarm.

Port runs just under 190 at cruise but the starboard will stay just under 200.

At troll or idle, 180 on port, 190 on starboard.

No alarm. No steam. No other symptoms. No strange smells or sounds.

After coolers brand new less than 2 yrs ago. Fresh water flushed each use. Impeller looked good, but is 2 years old. Diver cleans thru hills. And last clean was a week ago. Strainer looks good also.

Can a bad thermostat cause this issue? Or, can a bad wire connection cause a false reading on the gauge, and if so is there a way to check that.

Topic

[Mike P]

Question for Tony

Tony, would you recommend the 160 thermostats for a boat that spends 3/4’s of it’s running time at a 600 RPM idle? I’d also add that this is on lake Michigan where water temps rarely reach 70 degrees.

[Tony Athens]

You installed 160F high flow stats???

Tony

[Mike Pettee]

Still fighting this issue. New impeller. New thermostat. New sender. Acid flush. Vacuum out of raw water side. Still temperatures as below. Photos of gauges for both engines at respective rpms.

I’ve cleaned all connections but have not done the ground near the starter yet. Will keep updating as i progress.

[glenn111]

Mike, with your statement “At the dock, I let her warm up to the gauge read just under 190. Shooting the thermostat housing and the sender itself, it registered right around 177.” it seems to me that you don’t have a temp problem. The digital IR gun says your OK, even though your gauges are reading 190. I haven’t re-read everything, but perhaps I’m missing something, but you don’t need a new tstat. Seems like you gauge or what “feeding it” is at fault.

[Tony Athens]

Time for 160F stats………….Hurry!

Tony

[Mike Pettee]

Ok. New sender. Still hot. Ordered a new thermostat. Let’s assume that wont work, and I need to move on…

I keep reading issues with the exhaust nozzle spray at the elbow. Can someone elaborate? What would I check for this?

[Mike Pettee]

Bringing to top. The impeller piece removal did not fox the issue. I decided to stop and go get an IR gun before moving on to anything else.

At the dock, I let her warm up to the gauge read just under 190. Shooting the thermostat housing and the sender itself, it registered right around 177.

Leading me to believe I have bad sender or it’s something in the wiring. At 40 bucks I’ll start with a sender and work up.

Will keep updated.

[Rob Schepis]

Great pic Mike

[Philip]

I’ll bet that will fix your 10 degree difference….

[Mike Pettee]

glenn111 wrote:

What I really think “fixed it” was vacuuming the AC at the lower zinc input. If I remember correctly, I found some pieces of impeller in shop vac.

Like this one I found in there today. Odd the impeller I replaced was not missing a vane. It must have floated around causing no problems for years. Pulled it out but have not tested yet. Will report back. Also zinc time apparently.

[glenn111]

Mike, the IR gun makes a lot of sense. My analog gauges have never been accurate. I had a similar situation with my 330’s last year. Port engine ran hotter than stb engine (confirmed by IR gun) and was getting close to setting off the high-temp alarm. I hooked up a Barnacle Buster flush on the Port side for several hours. Connected the output flush hose into the lower zinc inlet of the Port After Cooler using clear/flexible hoses and pluming items from a hardware store. The flush return hose was connected to the output of the engine heat exchanger. There are several good articles hear regarding this procedure. Then connected the hoses to a bilge pump in a 5 gallon bucket of Bar Buster and circulated it as mentioned for several hours. Of course, removed all the anodes (total of three (3) – don’t have anodes on gear box HE) prior to this.
When I put everything back to normal after the flush, I still had higher temps on the Port engine. Then attached a shop vac to the lower zinc of the Port AC sucking out any impeller pieces. Then did a reverse flush with the Barnacle Buster for several more hours. Reconnected everything and NO more higher temps. What I really think “fixed it” was vacuuming the AC at the lower zinc input. If I remember correctly, I found some pieces of impeller in shop vac.

[Mike Pettee]

Glen I’m using gauges. Have not shot it with an IR gun yet as I do not have access to one. I guess a worthy purchase either way…I swapped the gauges. And it still shows warm so not the gauge. The pics below are port(lower temp) and starboard(higher). This was just after i pulled back from a 3 minute run at cruise rpm of 2600.

I may be worried about nothing, but am going to vacuum out the inlet raw water side of the aftercooler, just in case something hot wedged in there that made it past the strainer, as we do have a lot of grass in water here.

Will keep thread posted. Otherwise running fantastic .

[glenn111]

How are you measuring the temp differences…..digitally or gauges. Needs to be checked with digital temp gauge.

[Tony Athens]

Time for 160 Hi-Flow thermostats………

Tony

[Mike Pettee]

No dice. Had a broken clamp on the gear cooler to exchanger hose. Fixed that. Replaced thermostat to exchanger hose. Filled coolant, burped system. Still a steady 10 degrees hotter.

What I did notice, is its from the moment it fires up though. Start it, and 2 minutes later port side has not moved and starboard is reading the same 10 degrees up or so.

I’m leaning toward electrical, but finding and fixing a broken hose and clamp is good too.

Will update Sunday when I get back to it. Plan to pull and replace impeller, as its 2 years in anyway. And will pull and clean connections to gauge also……

[Rob Schepis]

It would effect system pressure so I would have to think so. Sea trial on Friday will tell. Keep this thread updated.

[Mike Pettee]

Thanks Rob. I will put on my list.

Could the tear in the coolant hose cause the symptoms above by drawing air into the system? I have the hose being replaced friday.

[Rob Schepis]

The 160 hi-flow tstat is perfect for guys that like to run on plane (fast cruise).

[Mike Pettee]

I may have found culprit.

I looked in engine room today and noted a coolant run near the back of the engine, almost under the drain. I contorted myself in there and noted. Broken clamp from exchanger to coolant pipe, but that wasnt leaking. The coolant trail led up to the front of the motor.

Worked my way up and the thermostat to exchanger hose had a tear in it. Squeezed it to see where coolant went when spurting from it and sure enough right to where the trail started and led back to the rear of the engine.

Not sure why I did not notice it yesterday. But. New hose is being ordered.

Seems minor, but could a small tear allow enough air in to allow the motor to stay that much warmer?

And lastly, are the 160 thermostats the way to go. Water temp I run in is often 88 to 90 degrees.

[Rob Schepis]

Try swapping the sending units (and cleaning all connections) and see if the temps follow the gauges or stay with the engines.

[Author]

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