overheat alarm

[gsdanno1]

just submitted a thread on this 30 mins ago , I don't see it . I found my engine temp sensor is slightly out of spec , going to replace and see if it has any impact on intermittent overheat alarm issues

[TownsendsFJR1300]

When's it going off, idle, high speed?

[gsdanno1]

original post that never posted : After months of repairs , took the boat out last Sat. , and had overheat alarm issues. 1st time was at WOT , shut boat down immediately for about 1 minute , restarted and everything was fine until the same thing happened at idle speed in a creek. Pressure at WOT 20 pi , at idle 0 , but I have never been able to read pressure at idle with the jackplate raised. Steady stream at the telltale in both instances. On the way home again at WOT , same thing happened with same results. Hooked YDS up and ran boat at the dock on Sunday . 20 mins 2200 rpm with 12psi , 20 mins @ 3200 rpm with 19 psi . Good flow thru telltale. Water temp high of 171 degrees . Pulled new t stat today just because , and it opens at about 150 degrees. Checked the thermoswitch and it checked fine with voltmeter per Yamaha spec. Checked engine temp sensor and it was out of spec per Yamaha - it was below the resistance spec at 68 degrees , and above at 212 degrees . I will replace and hope this fixes the problem . No stored codes , but I have come to find out that's probably because I didn't let the engine run at all while the alarm was on. This never has happened in the 9 years I have owned the boat . I don't believe in coincidences , so I'm betting on it being related to all the work I've been doing since last November

[TownsendsFJR1300]

My $'s on the sensor...

The cooling system is pretty basic and you've been thru most of it.

I don't remember, when was the last time the WP impeller was changed out?

I doubt your work caused this, stuff wears out, my starter relay failed with less than 200 hours...

I don't know what the normal water pressure would be, but 0 reading, I would think would show something. At idle, mine, even with a brand new WP kit, the flow tends to be weak at idle and picks up with RPM's (never an overheat issue).

[gsdanno1]

changed the impeller last fall , 10 hrs ago . going to order the sensor and hope

[gsdanno1]

re tested engine temp sensor with a better setup and new thermometer. It is fine . As soon as the wind lays down , I'm going out with my apprentice technician ( wife) so she can watch the telltale while I'm underway , at different speeds and trim angles and see what I can find .

[pstephens46]

Wind has been brutal in the southeast the past two days. Maybe you can run today and report back.

[gsdanno1]

took it out today , ran with the cowling OFF and the YDS hooked up. Put about 20 miles @ WOT ,broken up into approx. 4 - 5 mile runs. The alarm /light never went off. I had a buddy of mine looking at the telltale , which was , according to him , like a garden hose , and I was looking at the YDS readout. Temp climbed to 216 , at which point I came off plane and idled for a few minutes and it dropped below 200 . I then repeated , with same results. I have seen other posts that say the alarm is activated well below this temp , but I have never seen a temp operating range from Yamaha. The thermostat tested good - opened about 145 , both the thermoswitch and the engine sensor tested within spec according to my volt meter. I'm wondering if running with the cowling off helped keep the alarm from sounding , although engine temp sensor is mounted at the top of the motor and was giving the 216 degree reading . Obviously need to learn more !

[99yam40]

always post what motor you are talking about in the 1st of thread.

seems like there may be a need for both sensors and switches to agree on some motors that the motor is over heating before alarm sounds.

216 sounds like too high to me, as it is over the boiling point of fresh water.

others will have to post

[fairdeal]

seems like there may be a need for both sensors and switches to agree on some motors that the motor is over heating before alarm sounds.

216 sounds like too high to me, as it is over the boiling point of fresh water.

For the F150 , the numbers I've seen are:

overheat via thermoswitch is between 183-194 - that's measuring water temperature exiting the thermostat

overheat via engine temperature when the ECU sees 266 F (sensor set into the metal of the block)

(IMO that's pretty dam hot)


and yes, based on the testing I've done on my F225, there is likely logic programmed in to require some agreement before alarming for temperature.

(the F225 will throw a "check engine" if the two disagree)

[gsdanno1]

have not accessed pressure control valve. Exhaust manifold replaced in the fall, very strong water stream , so I would think there is good flow through the engine . I found it odd that no alarms went off today , as the only thing that has changed since the last time I ran , when alarms did go off , was that I pulled and checked , thermostat , thermoswitch and engine temp sensor . Will pull pressure control valve tomorrow

[jcclub47]

Doo Hicky settings

If you have digital gauges there is pins or tabs on the back of the digital guage that denote 4 stroke vs. 2 stroke for the alarm. It won't hurt to make sure that they are in the correct position.

Good Luck
Joe

[gsdanno1]

will check , but I never had an issue before I tore everything apart last fall

[pstephens46]

Sounds hot but also sounds like a mission. I may take my laptop on boat this weekend and see where my F150 temp ends up after a couple hard runs. Hopefully my son will visit from college. Don't trust my wife at that speed. It takes forever to warm the engine at idle.

[gsdanno1]

Thanks , I'd appreciate a comparison .