1986 Mercury 90hp Help with Temp Sender / overheat

[Imjus4u2nv]

I am in the process of fixing up my 90hp 1986 mercury Tower of Power, serial # 0A968445, model 1090726.

I had an issue with a cylinder overheating in the past, but still have good compression. I was running it on 5 out of 6 cylinders, but now after replacing switch packs have spark on all 6 cylinders. Before firing it up on all 6, I want to install a water temp gauge and a temp gauge.
I have read all the info here about them and have decided to do both.

I am having an issue finding the part (or a cheap part) for the temperature sender, that would go next to the top spark plug. According to mercury, factory replacement is part #87-96829A1.

Does anyone know what this part does? Is it just an overheat alarm, or can I actually plug it into the temp gauge I ordered (from Faria for $10 bucks https://faria-instruments.com/store/index-mart.php?cat=Water Temperature) and get a temp reading (I understand unless I overheat I will likely not get any temp reading). If it is a temp alarm, what do I hook it up to?


I was also wondering if i had to use part #87-96829A1, which runs for about $150-$300. I have looked up some other senders (thinking these may be for the water temp:
Faria 90401 (https://faria-instruments.com/products.php?calledGauge=4_temp)
Sierra 18-5896 (http://www.iboats.com/Mariner-Temperature-Senders/dm/view_id.270127)

Does anyone know if these will work instead as they are about $20 bucks.

As always any help is greatly appreciated (not sure if helpful but my engine does not have a head gasket, just a water jacket with two 'holes' for sensors).

 

[Georgesalmon]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

Why don't you get the sender that's available for the gauge you want? The sender number is right under the gauge picture.

 

[racerone]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

These motors never had any temperature senders or warning system for many , many years.-----If you replace the impeller every 2 years as you should , then temperature gauges are not really required.----A water pressure gauge is very useful and I believe much cheaper too.

 

[Imjus4u2nv]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

Why don't you get the sender that's available for the gauge you want? The sender number is right under the gauge picture.

Thanks for responding, I am pretty sure I need a specific sender to match the motor but i could be wrong, that is why i am trying to figure out what the factory part# i provided did, so i could find the correct replacement.

 

[Imjus4u2nv]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

These motors never had any temperature senders or warning system for many , many years.-----If you replace the impeller every 2 years as you should , then temperature gauges are not really required.----A water pressure gauge is very useful and I believe much cheaper too.

My potential source of overheat appears not to be water pump related, and while I think I fixed the issue, I do not want an overheat from running lien condition.
Thanks for responding, i see now from your response that they did not come with them but there are two holes in my water jacket so I would think I could add aftermarket?
1) One appears to have threads and does not enter the water jacket (right next to the top sparkplug.
2) another hole has a brass fitting in it, I believe if I remove that fitting I will have access directly to the water in the water jacket.
I believe measuring temperature would be best if done from spot 1, as it would measure temp through metal rather then water and probably be more responsive. I need to know if the factory replacement part can be hooked up to a temp guage, or if need to buy a horn/alarm of some sort (and if some which one).

 

[racerone]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

Your local dealer can assist with the accessories for your motor.

 

[Imjus4u2nv]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

I am hoping someone here can

 

[Imjus4u2nv]

Re: 1986 Mercury 90hp Help with Temp Sender / overheat

Bump