installing a temp gauge 99 200 Johnson

brokeboater

Petty Officer 2nd Class
Joined
Sep 17, 2002
Messages
103
I picked up a OMC temp gauge from a marine surplus store a while back and am debating how to install the sending unit. the instructions say a head bold can be removed and the bracket put under the bolt to screw the sending unit into or one of the existing holes in the head may be used to screw the sending unit into. which way will provide the best result?

if i use one of the holes, do i need any kind of heat sink grease in the hole? thanks
 

brokeboater

Petty Officer 2nd Class
Joined
Sep 17, 2002
Messages
103
Re: installing a temp gauge 99 200 Johnson

thanks. guess i'll use the hole in the head. i'll be off to buy some heat sink compound.
 

brokeboater

Petty Officer 2nd Class
Joined
Sep 17, 2002
Messages
103
Re: installing a temp gauge 99 200 Johnson

i did the install on this gauge saturday. i am concerned however about its accuracy. running on the garden hose in the yard it tops out at about 180-185. my manual says i should be looking for about 125-130 with a pyrometer or the wax melt stuff. would the fact i have installed this in the head be the reason it shows a much higher temp?? 160 i think is where the redline starts.
any ideas?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: installing a temp gauge 99 200 Johnson

You more than likely have an incompatibility problem with the sender and the gauge. They need to match or you end up with inaccurate readings.
 

brokeboater

Petty Officer 2nd Class
Joined
Sep 17, 2002
Messages
103
Re: installing a temp gauge 99 200 Johnson

the sending unit came with the gauge. it was an older unit made by OMC.
how would i know how to match the gauge and sending unit?
 
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