97 Vmax 150 - mechanic replaced the thermostats and water pump, still overheating!!

[99yam40]

I have found from personal experience (many times) that some after market parts are not worth the few dollars saved, water pumps especially, these days I will not fit, advise or help anyone fit an aftermarket water pump, some parts are OK, but, certain parts, no, not a chance.

I once installed a Yamaha impeller only I got from a local dealer and it came apart in less than a year.
no telling how long that sat in a parts bin before I bought it. I now just buy the kits.
housing does not come in the Yamaha kits, but aftermarket does

[aphextwin]

We didn't home until late last night but we managed to put it in the water! Started up no problem, but first thing we get is the buzzer going off. I looked at the tachometer and all four signals went off....high temp, low oil in both engine oil tank, remote oil tank low, and too much oil in in engine oil tank and remote oil tank. I will reference the below image. Eventually it settled to just the high temp and yellow light.

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Here is the pic of my tachmoter from youtube.
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Let's deal with the high temp right away. Taking my infrared gun, the top left and right cylinder heads were 110 and 112F. We idled for about 5 minutes and both stayed consistent temp. We then took it for a spin at medium throttle and it was still fine and never went over 115F and checked all 6 if it was maybe one particular one. I assume we couldn't go WOT as the engine goes into "limp mode" right as long as it was buzzing? I did try and it just chugged. It was on the whole time we tested the boat. Is there another place it's overheating? Is it a faulty sensor perhaps? I never had the high temp buzzer go off at all when I ran those engine test (thermostat cover off, on, propeller exhaust in water etc)

The lights eventually settled to just the overheat and the yellow light. So after 30 minutes we took it back to land.

Going to the oil lights issue...it did eventually settled to just yellow light and high temp. However, when I checked my remote engine tank and engine oil tank when we started they were both full and the engine oil tank was in spec. I did notice that by the end of our run, the oil went below the minimum mark. I've attached the following image from home. I will check oil filter for clogs and oil hose kinks as something isn't here since the remote oil tank is still full.
image_5953.jpg


So now going back to the high temp. Am I missing something that I am not checking where the engine is overheating?
tempgun.jpg
Above pic is from home (you can see here t-stats are off and water if flowing down it) as I didn't take a pic when I was on the boat but can confirm the temp was never above 115F even at idle or while moving and I checked multiple times. It didn't have a problem starting after turning off multiple times.

What do you guys think is causing high temp light?


And at this point, can I rule out that I don't have an overheating issue based upon the cyc. head temps on the lake?

So next steps. (and yes I will go out and get the service repair manual now that I know I don't need to spend $2000 to remove the engine to get to head gasket right??)

1. Am I missing taking the temp from somewhere else? I only checked the cylinder heads the whole time.
2. Engine never died but I suspect the yamaha's go into limp mode?
3. Faulty sensor?

[99yam40]

"Started up no problem, but first thing we get is the buzzer going off. I looked at the tachometer and all four signals went off"

this sounds like the motor did not have time to heat up to normal much less overheat.
Is this true?

with multiple things indicating there was multiple problems, maybe your just having a low voltage problem causing things to go wacky

[aphextwin]

Yes it didn’t warm up, it was right when I turned on. Basically the whole thirty minutes I had the buzzer noise going off even after multiple starts etc. should I be able to turn on stereo and trim controls on the outboard even if I don’t have keys in ignition? The previous owner had put a *****ing motor attached to the outboard and that can turn on off without ignition? So basically check the wiring?

[99yam40]

as I said maybe the CDI or ECU is seeing low voltage causing the alarms

[Jason2tpa]

The trim controls should power on when you turn ignition key on because they are tied direct to the ignition harness. Other accessory loads such as a stereo are not likely powered by your cranking battery, or at least they shouldn't be.

In regard to the oil injection system, the oil alarm is being triggered because the oil level is below the bottom mark on the main tank as you've already discovered. When you turn the ignition key ON the oil level sensor will trigger ON the reserve tank pump if the oil level is low. If the main tank is not filling then either the pump isn't working or circuitry has an issue (oil harness).

In regard to the overheat issue, have you tested the thermosensors and pigtails for continuity?

[aphextwin]

The previous owner connected everything to one battery including the stereo and *****ing motor. Reading online,
I should:
1. go buy another battery to work as a house battery
2. buy a switch like the one below?
Marine Switch.jpg

For the overheat, I haven't tested the thermosensors and pigtails (what is a pigtail?). Do I just use a multi tester for that? Should I also disconnect the accessories for now to make sure those aren't interfering?

The trim controls should power on when you turn ignition key on because they are tied direct to the ignition harness. Other accessory loads such as a stereo are not likely powered by your cranking battery, or at least they shouldn't be.

In regard to the oil injection system, the oil alarm is being triggered because the oil level is below the bottom mark on the main tank as you've already discovered. When you turn the ignition key ON the oil level sensor will trigger ON the reserve tank pump if the oil level is low. If the main tank is not filling then either the pump isn't working or circuitry has an issue (oil harness).

In regard to the overheat issue, have you tested the thermosensors and pigtails for continuity?

[aphextwin]

Thank you 99yam40 for the advice. So I called my bro in law who is an electrician....he is going to come to test out the wiring. Hopefully he can teach me some basics.

as I said maybe the CDI or ECU is seeing low voltage causing the alarms

[99yam40]

Thank you 99yam40 for the advice. So I called my bro in law who is an electrician....he is going to come to test out the wiring. Hopefully he can teach me some basics.

I have read that some motors will alarm from low voltage, maybe Boscoe99 can say if this motor is one that does or not

[aphextwin]

I think I have the 1997 Yamaha 2-Stroke Series D150TLRV? Serial Number sticker was missing so I had to look up the family model.

yamaha_models.gif

here is a pic of the motor in all it's old glory....:]

Yamaha Model.jpg

I have read that some motors will alarm from low voltage, maybe Boscoe99 can say if this motor is one that does or not

[Jason2tpa]

The thermo switch triggers the high temp alarm when the bank reaches high temp. The switch is closed at normal operating temp (discontinuity) and opens at high temp (continuity). With engine off/cold and your multimeter set to continuity, unplug the 2 pigtails for each switch and attach meter probes to switch leads. If the switch has continuity then it’s bad. If it doesn’t then pull the switch and test continuity at high temp. If continuity at high temp then switch is good. There is 1 thermo switch assembly per bank.


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[aphextwin]

Hey Jason, thank you for this, super helpful.......! Appreciate it.

The thermo switch triggers the high temp alarm when the bank reaches high temp. The switch is closed at normal operating temp (discontinuity) and opens at high temp (continuity). With engine off/cold and your multimeter set to continuity, unplug the 2 pigtails for each switch and attach meter probes to switch leads. If the switch has continuity then it’s bad. If it doesn’t then pull the switch and test continuity at high temp. If continuity at high temp then switch is good. There is 1 thermo switch assembly per bank.


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[99yam40]

The thermo switch triggers the high temp alarm when the bank reaches high temp. The switch is closed at normal operating temp (discontinuity) and opens at high temp (continuity). With engine off/cold and your multimeter set to continuity, unplug the 2 pigtails for each switch and attach meter probes to switch leads. If the switch has continuity then it’s bad. If it doesn’t then pull the switch and test continuity at high temp. If continuity at high temp then switch is good. There is 1 thermo switch assembly per bank.

you wording is wrong
open is normal and discontinuity
closed is when too hot and continuity

[aphextwin]

Found this if this is useful for anyone else.
https://maxrules.com/fixyamahawiring.html



Yamaha Wiring Color Codes.jpg

[aphextwin]

Thanks Jason, so I was able to pull it out and checked. Stock is no continuity and hot it opens up. After cooling down it goes back to no continuity.

Now looking at the service manual for possible overheating issues.

Passed
1. Thermostat - checked and does open up at high temps
2. Thermoswitch - checked for continuity no issues
3. Water Pump - mechanic replaced them
4. Water passages - Was able to get water out of the thermostat covers and was able to monitor temp of cylinder heads (they were at 120F tops on the lake)

Haven't checked
1. Charge Coil - haven't checked
2. Spark Plugs - mechanic put new ones in (could he have put in wrong ones?)

Also, when I brought boat home. I moved key to ignition, buzzer went off. I topped the oil and and no more buzzer.

99Yam40 - You mentioned to check for low voltage. My bro in law hasn't come over yet but when he said the reason potentially why all the warning lights went off was because it's on the lake it's a sustained voltage. That makes sense to you?

And how do you fix a low voltage problem? Is that checking the
1. Lighting coil
2. Rectifier/regulator
3. Fuses
4. Battery Leads
5. Battery

When checking R/R, I need to remove it right not test it connected to the engine?

Thanks

The thermo switch triggers the high temp alarm when the bank reaches high temp. The switch is closed at normal operating temp (discontinuity) and opens at high temp (continuity). With engine off/cold and your multimeter set to continuity, unplug the 2 pigtails for each switch and attach meter probes to switch leads. If the switch has continuity then it’s bad. If it doesn’t then pull the switch and test continuity at high temp. If continuity at high temp then switch is good. There is 1 thermo switch assembly per bank.


540EA62A-8047-4F12-A00F-B7B36BDC569D.jpeg