Any way to add a temp gauge/sensor?

[swamp-fox]

I have a 1978 90hp merc. Is there anyway I can add a temp gauge?

I noticed on the 115 of the same year, there is threads going into the block by the #1 spark plug. I was thinking that is what they were for.

 

[swamp-fox]

Re: Any way to add a temp gauge/sensor?

bump

 

[Silvertip]

Re: Any way to add a temp gauge/sensor?

You buy the guage, sender and then follow the directions. A temp gauge can be added to any engine but the gauge and sender must match. If the sender is a "contact" style you technically have a cylinder head temp gauge. If the sender screws into a port in the water jacket you have a water temp gauge. Outboard senders are typically 33 - 240 ohms (hot - cold). Faria and Teleflex both sell them.

 

[swamp-fox]

Re: Any way to add a temp gauge/sensor?

Ok well I guess I will have to do some more investigating when I get home.

I know the 90hp has one set of threads that I will use for the water pressure gauge. I'm hoping to add a temp gauge, because my boat is inclosed and I can't turn around and see if it's peeing. I wanted 2 fail safes.

 

[Faztbullet]

Re: Any way to add a temp gauge/sensor?

A temp guage will not work on your motor as it has no t-stat, the guage would read cold all the time. The small threaded hole beside #1 is for a overheat sensor OEM # 87-96829A1 and they are about $175 and break easily. You best to minstall a 15psi water pressure guage to moniter water pump performance...

 

[swamp-fox]

Re: Any way to add a temp gauge/sensor?

Ok thanks Fazt

On the 90 the water jacket doesn't have the hole cut out by the spark plug. I was thinking it probably still had the threads on the block like the 115, so I was just going to swap water jackets. However I really didn't want to start that if it's not worth it because I don't fell like snaping bolts.

When you say they break easily what exactly do you mean. Upon instalation? or just go out like the trim limit switch? (where can I get one of those also I've looked everywhere)

When it's all said and done, I will have over $1000 in it so an extra $174 won't matter if it will help save the motor. I guess I'm just thinking to much.....I do have a water pressure gauge that I will put on it though.

 

[Chris1956]

Re: Any way to add a temp gauge/sensor?

Just install the water pressure gauge. Remove the telltale elbow, and install a brass tee into the waterjacket. Now install the telltale elbow on one side of the tee and the water pressure fitting on the other side of the tee.