Outboard identification

[mulli grub]

Hi,
New to the forum so im sorry if this has been asked before.
I have a 115hp Yamaha v4 outboard with no tags or plate on outboard anywhere.
I was wondering if there is a way to tell how old this outboard is, The cowl and stickers on it are not the original.
The rego slip does have a engine number on it. is there a way i can find out from the engine number.
I have been goggling the part numbers and it gives me a 12 year range (1984-1996).
Would like to find out what it is exactly.

[boscoe99]

There should be an alternate ID tag on the block itself. Usually in the vicinity of the starter motor. It is round and will have numbers on it. What are the numbers?

What are the numbers on the registration paperwork? They should agree with the numbers on the block.

[mulli grub]

hey, yes i did find the number its 350377 and does match whats on rego.
?

[almetelo]

By the S/N is 1984 model

[mulli grub]

Thank almetelo.
Thats what year i was thinking the whole time.
Can i ask how you got the year just buy the number?

[almetelo]

I got it from my data

1984 was 1st year of a 115 with precision blend / autolube

[mulli grub]

Thanks mate.
Sound like you know your stuff.
I don't know if you can help me or not.
Im having troubles with overheating(buzzer sound).
I have replaced the heads, thermo switches, poppet vales, thermostats.
Worked fine for about 3 trips after was all replaced, then back to overheating(buzzing sound)!.
I also used a temp gun on the heads and around them when the buzzer was sounding and both heads where around the 68 degrees Celsius, according to the manual for that outboard thats normal operating temp? .
Water pump impeller is fine and is peeing water out hole.
Just at a loss now!, not sure what to do? Do i just unplug the sensor or is it something else?

[99yam40]

You did not post that you ever replaced the water pump impeller, cup ,wear plate, gaskets/orings, and housing.
These all except the housing need replacing on a regular maintenance time line as Yamaha recommends. The housing needs replacing when signs of wear or melting.

But the over temp alarm should not sound until the temp gets to 90- 96 C.
Hopefully you did not put the wrong switch in the alarm spot. They are easy to test by putting into a pot of water and slowly heating while monitoring the temp of water and watching when the switch closes and opens back up when cooling off to make sure it operates in spec.

Are you sure it is an over heat alarm that is coming in?

[mulli grub]

Hi 99yam40, thanks for the comments mate every little bit is helping me out.
No i have not replaced the impeller or any of that because i think its in good condition, impeller is not broken cracked or warped, plate has a few little wear marks on it, and cup looks brand new, housing looks old but in OK condition and the o ring looks OK.(have attached pictures).
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You say it is easy to test the switch?, are you talking about the thermostats or the temperature sensors?.
I have pulled the new thermostats out and tested them in hot water to see if they open and close and both did.
Is it possible i have the wrong temperature sensors in the heads?The reason why i started this thread was to identify the year of my outboard so i can order the correct parts for it. the year outboard i ordered parts originally was 1984.

I'm not totally sure it is an overheating alarm, I have read a lot on the internet about this topic and almost everyone is saying it is (overheating or Oil) and i figured it is 2 stroke it cant be oil?
Is this correct?
What else could be sending the alarm off?.
Please help.

Cheers

[99yam40]

oil injected motors have a low oil level that will set off the buzzer.

If yours was oil injected and someone removed it then you could still have wiring issues if they did it correctly or wrong

I was referring to the over temp switch.
I do not think a motor that old will have a sensor
The switch should be an open or closed contact.
need to monitor the water temp in the pot with a thermometer even when testing the stats to see what temp they and the switch open and close to see if they operate in spec.
Locate the over heat switches so you can disconnect them one at a time next time is happens to see if one is causing the alarm


Yamaha recommends replacing the water pump on a regular bases.
If you have no idea when it was replaced last then I would get the kit and do it right.
Had a friend that had his rubber impeller break free of the plastic hub so it would not spin except are low RPMs. He had to call for a tow after it failed even at low RPMs and could net make it all the way back to the ramp. He had not replaced his in many years
I have had pieces break off of my impeller before. I had installed just an impeller less that a year before. I think it was an impeller that sat on a shelf for a long time at part store or I started motor with it tilted out of the water.
Everyone buys kits for just a few dollars more than the impeller itself, so it could have been just old

Nothing is worse than impeller screwing up a fishing trip because the proper maintenance was not done.
Maybe stranding you in dangerous conditions would be worse

[mulli grub]

image.jpg
I have two of these both in the top of each head. Is there another switch im not seeing?.
If it was oil injected how do i tell? And what can be done to fix it?.

[99yam40]

orange wires should be indicator for motor is warmed up,
Pink wire on switch would be the signal for over heat.

At least that is the way my C40 is set up