3.7 Warning system

[MTBoat]

Last year I overheated my engine due to kelp blocking the intake; no buzzer or warning. Then this spring the valves stuck and push-rods bent.
Rebuilt the head and better than new.
Then, I bought an early warning buzzer systems to install, and it requires screwing in temp sensor somewhere coolant runs (I have closed cooling system with antifreeze) and requires a T into the existing sensor where oil pressure is monitored from.

***Does anyone have knowledge of where these little places are on this engine? Or photos or links?

I want to make sure I can never overheat again, or run low oil pressure without the buzzer going off; it was a costly mistake.
Thanks

***Oh, and how many hours running before I re-torque the head bolts, or do I need to?

 

[stonyloam]

I think there is an extra plug on the underside of the exhaust manifold that you MIGHT be able to use. See # 3 here https://www.mercruiserparts.com/Show...%28ALUMINUM%29 For the retorque of the head bolts, bring it up to operating temp ONCE, then Retorque. The manual says bring up to temperature and Retorque. It is not clear whether you do it when the engine is hot or cold. I did mine hot, other guys have done it cold. Either seems to to be OK.

 

[philbullet]

Another alternative like I did when I had the 3.7, is buy a Murphy mechanical temp. Gauge with the alarm feature. U can set the desired temp. And buy a 12v. Buzzer from radio shack.
I bought mine from Donavan marine with 20' wire to reach the dash control.http://www.fwmurphy.com/uploaded/temperature_20T.jpg

 

[Bondo]

Then, I bought an early warning buzzer systems to install, and it requires screwing in temp sensor somewhere coolant runs (I have closed cooling system with antifreeze) and requires a T into the existing sensor where oil pressure is monitored from.

***Does anyone have knowledge of where these little places are on this engine?

Ayuh,.... The Best place is in the T-stat housin' next to the temp sender,.....

 

[thumpar]

The factory puts the temp switch for the alarm in the thermostat housing. For the oil you will probably have to Y off of the oil pressure sensor.

 

[MTBoat]

Thanks, I have now located the needed spots, as recommended, and can easily install the temp sender unit, however, the t or y of the oil pressure is amazingly difficult to find, NAPA couldn't get me the right item, and Ace had 1/4 inch ts but wrong threads and size....Fasteners inc may be able to do the job,,,just didn't expect find a simple t to be such a time consuming search.

 

[stonyloam]

this might do it. I think you have 1/8 27 thread. Check with the seller http://www.ebay.com/itm/like/351369...%3D711-117182-37290-0%26rvr_id%3D823197336243

 

[Bondo]

Thanks, I have now located the needed spots, as recommended, and can easily install the temp sender unit, however, the t or y of the oil pressure is amazingly difficult to find, NAPA couldn't get me the right item, and Ace had 1/4 inch ts but wrong threads and size....Fasteners inc may be able to do the job,,,just didn't expect find a simple t to be such a time consuming search.

Ayuh,... It should be 1/8' pipe thread, as Stoney says, which IS available everywhere, includin' where you've been,....

 

[achris]

Merc sell them too, part# 22-286241, cost you all of $9.

Chris.....

 

[MTBoat]

Got er done! Fasteners, Inc had exactly the part as you showed the link for, and it fit perfectly...tested it all out and works great. Never again overheat, drop oil prussure or lose the engine over an easy fix. The new head and hardened valves seats have it running like new however; the upside
Thanks all.