130 hp Johnson Water Pressure Gauge Install

[louluvscookies]

I've got a 1995 130 hp johnson that I've been having problems with overheating, so I decided to install a Water Pressure Gauge and Cyl. Head Temp. gauges. Trying to figure out where to tap into the waterjacket for the water pressure gauge. It is a Faria water pressure gauge and in the instructions it says that there should be a plug already someware in the water jacket. I have looked all over and all I see is a 1/8 threaded hole in the head next to the factory temp. sender. It isn't drilled through. Wondering if thats what its there for or not. Any Info. Would be Great. Thanks

 

[Will Bark]

Re: 130 hp Johnson Water Pressure Gauge Install

Try teeing off where the "pee" hole comes out of the engine

 

[louluvscookies]

Re: 130 hp Johnson Water Pressure Gauge Install

Will that give an accurate reading? Just wondering because it seems like it would be less pressure because its not restricted.

 

[Silvertip]

Re: 130 hp Johnson Water Pressure Gauge Install

Think about it! That hole is no more than a pin-hole in the grand scheme of things. Look at the size of the hole in the prop where the exhaust comes out. That hole is also where the cooling water comes out. Now ask yourself, is this really a problem. Fact is, put a T in the tell tale and try it. Then put your finger over the tell tale to see just how much the pressure rises. That will prove or disprove the issue. On some engines that does not work because of the design of the cooling system. I've not seen an engine that this did not work but then I've not installed a WP gauge on every engine on the planet. There is no concrete number for what water pressure should be -- even on the same engines. So the key is to install a new water pump and take pressure readings at idle, 1/2 throttle and wide open throttle. Note those readings. Down the road any deviation from those numbers indicates the impeller needs attention. The actual number after installation of the gauge is not important so long as you know what the reading is with a new impeller.

 

[dazk14]

Re: 130 hp Johnson Water Pressure Gauge Install

There is a tapped 1/8"Npt hole from OMC for this application in the exhaust housing adapter.

It is located on stbd side just aft of the side cowl stud. You may need to wire brush the crud off to see it.

The stainless steel plug is a 5/32" allen socket and they do stick, especially in salt water.

I have tig welded an allen wrench to them before to get them off after stripping the plug.

 

[louluvscookies]

Re: 130 hp Johnson Water Pressure Gauge Install

Found the plug and it came right out. Thanks for the info. I would never have found that plug! Thanks for all the advice.