2006 Mercury 90HP 4 Stroke Temp Gauge

[bruceb58]

I have a water pressure gauge but I would also like a temp gauge. I ran all last year with a thermostat that ws stuck open and would prefer to know when that happens again.

What are my options to adding it to this engine? It has the head made by Yamaha.

 

[Fun Times]

Isn't your engine is EFI?
Thought you installed a mercmointer?
http://www.livorsi.com/catalog/merc_monitor.htm

Temperature gauge on outboard? Page: 1 - iboats Boating ...
Water Temperature Monitoring- Outboards

1. The temperature monitoring kit includes all parts to adapt to any of the situations noted above. Yamaha engines will require an adapter P/N 61886P in addition to the kit.
2. Outboard engines use raw water for cooling and are mostly aluminum, so they operate cooler than stern drives. Consult dealer or engine manual to determine maximum operating temperature of your engine.
3. The sender in the kit has 1/8-27 NPT threads with I.D. Code "10" or "60" stamped on the hex. Senders stamped "230" won't work correctly.
4. Part number of the sender is 52320S010; the flat bracket is 54552; the Z bracket IA55009.
5. Some engines include a threaded hole directly into a water line. The temperature sender can be threaded into the hole, using no sealant on the threads. The threads create the electrical ground.
6. Some engines have a blind threaded hole for a temperature sender that does not enter the water jacket. After applying thermal compound to the hole, thread the sender in snugly, again using no sealer.
7. Some Mercury engines have a blind hole flanked by two bolts. These are for tightening the flat plate. First place thermal compound in the hole, then drop the aluminum spacer in the hole. Thread sender into bracket over hole until it hits spacer.
8. The Z bracket installation is used most often as it fits any engine. The Z bracket through hole is held by any one of the engine's cylinder head bolts. The sender is threaded into the bracket's remaining hole down against the cylinder head. Scrape the paint from the head under the sender to get good thermal transfer.
9. The kit is supplied with one sender. If a sender is desired on each cylinder bank on V type outboards, a double pole ON-ON switch must be used to switch sender input to the gauge. The gauge can not accurately handle two senders at one time.
10. Testing the gauge for operation: Connect a hot wire to "I" and ground wire to "G". Gauge should read below the C. Next, Short the "S" terminal to "G". The pointer should go above the H. If the pointer sweeps this way, the gauge is fine.
11. Testing the sender: At room temperature, with no wires on the sender, it should measure approximately. 600-800 ohms on test meter.
12. Replacement outboard sender IA96035 cannot be used with this gauge. The gauge will read very high. IA96035 is only for pre-1995 Johnson/Evinrude engines with a 50-250F gauge.

 

[bruceb58]

According to Mercury, Smartcraft won't work on my engine since it's a Yamaha head.

I was reading my service manual last night and I do have a port that might be available but it might also be the port that is currently used by the water pressure monitor. I would like to keep both if I can. When I pull the boat in a few weeks I will see if that is being used.

Not really interested in a cylinder head temperature reading. I want water temp readings.