MnFastBoat

Anyone know if there is a stock part from Napa for this?
I cannot find a Merc part # at all for it, as neither can Marine Max!!
1999 Merc 502MPI, non closed cooling
First parts photo does not show the Sending or Temp plugs in the Thermo housing,
Second photo shows it as #18 on the EFI parts drawing. That is what I need.

I have changed 2 Thermostats on the port motor due to no reading on the gauge.
Always ran cold, so cold that the transom was BLACK!
Change the stat out and the first hour read up to temp and ran great!
Later in the day it was back reading @ 100 degrees. But I was never able to run hard again to see what it would run like.
Changed another Stat out, and it still read 100. Starboard motor has always temped out fine.
Basic trouble shooting on the water, I pulled the connector for the Water Temp sending unit and the needle dropped!
So it has power at the plug/wire.
My next guess is to change the Sending unit. If I cannot find one today, I plan on swapping between the port/starboard to see if it follows.

Thanks

lakematdude

Mercruiser part number 806490T item number 6, http://www.mercruiserparts.com/Show_...arness+Bracket

Merc # 806490T = Sierra Part # 18-5897. Sierra can typically be found at napa auto parts. You'll be happier to get an OEM part vs a sierra part. The OEM part will be easier & overall cheaper to install due to the OEM already comes with the sealant on the threads where Sierra does not. And to buy the correct sealant could cost as much as 18.00 depending on where you buy it.

http://www.iboats.com/Boat-Parts-Acc...n_id.630489171

MnFastBoat

Thank you!

Steve H

Don't forget that you have two temp senders. One for the gauge and another for the computer.

MnFastBoat

Was not the sensor, but more rocks holding the thermo open

Cole2534

iTrader: (1)

Is this a joke?

lakematdude

No, Not in my opinion while looking it up for him.

Tinkerer

$18.00 for Teflon tape or pipe dope. I don't think so.

mike tkach

iTrader: (3)

1.69 oz container of arp thread sealer is under 10 bucks,you could install a lot of sending units with that!

lakematdude

Yes you could if you do use thread sealer all the time before it has a chance to go bad. But for a one off guy doing it himself at home for the first time/in a long time, most likely chances are he may not have it sitting around, and if he did, maybe he can't recall exactly where he set it last. So what do you do, go to the auto store and buy a new one for 5, 10 + dollars when all he has to do to make life a bit easier is buy the OEM sending unit or the one from Mallory would work that already has the better OEM red sealant applied to the threads and all he has to do is just install it and be done. Less chance of making a mess by not having to deal with sealant on your hands, upholstery, worry about if he's adding to much or to little sealant, etc.

The sending unit from Sierra does not show or have the sealant applied so you would need to buy some. So with that said, let's look at the list price only for this example as we all know just about everything online is typically on sale somewhere as long as you do your homework for best price.

Installing brass type fittings using the Mercruiser service manual basically says use either # 592 loctite pipe sealant with teflon on threads of brass fittings or plugs Or on certain mentioned fittings use quicksilver perfect seal. Do not use teflon tape.

Quicksilver perfect seal part number 92-34227Q02 MSRP $18.32

# 592 loctite pipe sealant with Teflon 50 mL Tube obtain locally,
Quantity Price 1-15 $18.57
16-86 $14.30
87+$13.28
http://www.ellsworth.com/henkel-loct...th-ptfe-50-ml/

The original poster (MnFastBoat) sender part number needed is 806490T.
http://www.mercruiserparts.com/partsByNumber.asp

Mercruiser sender MSRP is $26.42

Mallory sender MSRP is $22.49

Sierra sender MSRP is $23.99

Found in the link below both Mallory & Sierra can be seen, one with no sealant on the sierra while Mallory does have sealant,

http://www.iboats.com/Boat-Parts-Acc...n_id.630489171

So basically before uncle sam and shipping or gas to the store once again, there is a $3.93 difference between the three sender options before you realize (especially if you don't do this all the time) that to save 3.93 buying aftermarket I now need to go spend $5.00 + when I could have just bought the oem part and be done sooner not to mention supporting your local dealer that is there for you if or when needed.

Yes i'm aware there are cheaper options available out there and this example is not always the case, but if you're doing your home work before hand, you might as well find the easiest way of doing it as well if at all possible.

Now take in the trusted quality difference between Mallory & Sierra vs OEM. For a $3.93 difference to have a better chance to do it right the first time? count me in on that las vegas trip.

http://www.offshoreonly.com/forums/g...tite-fail.html