Water Pressure guage install 75hp Mercury 4-stroke

[brumbyvet.1044]

I bought a Teleflex 65507P water pressure gauge kit to connect to my 2009 90hp EFI-4S. I need this gauge to match the rest I have. I planned to get the Lagree fitting since my toon was rigged with the 5/32" line, but the gauge doesn't have a fitting that size. The kit came with 1/4" line so I installed it and inserted a T-fitting into the tell-tale. My tell-tale was already T-'d to the fuel pump assembly though, by a hose that feeds up from the lower unit. I only get 5psi underway, but the tell-tale is fine and it doesn't overheat. Any suggestions? TIA

Mercury makes a special fitting that screws into the block for this motor. I have the same motor as yours and I get about 15-20 psi underway.

[kryptonite]

Wow this thread is old....

But anyways, when you tap the tell-tale its harder to get a good reading.

Where I'm tapped into the block I think at WOT I'm up around 25PSI

[tommyz]

I bought a Teleflex 65507P water pressure gauge kit to connect to my 2009 90hp EFI-4S. I need this gauge to match the rest I have. I planned to get the Lagree fitting since my toon was rigged with the 5/32" line, but the gauge doesn't have a fitting that size. The kit came with 1/4" line so I installed it and inserted a T-fitting into the tell-tale. My tell-tale was already T-'d to the fuel pump assembly though, by a hose that feeds up from the lower unit. I only get 5psi underway, but the tell-tale is fine and it doesn't overheat. Any suggestions? TIA

Mercury makes a special fitting that screws into the block for this motor. I have the same motor as yours and I get about 15-20 psi underway.

Yep they do, and it uses a 5/32" line. Problem is, the Teleflex Lido gauge comes with a fitting that won't take something that small and I can't find anything that will. So what gauge do ya'll have that accepts a 5/32" line?

[tommyz]

Thought I'd post an update to this old thread after solving my dilemma.

I bought the Lagree fitting as recommended and used the 5/32" line rigged from motor to helm. My gauge came prepped for 1/4" line so the 5/32" line wouldn't fit over that barb. However, the 5/32" line slips tightly into the 1/4" line, so I used a short piece of the 1/4" as an adapter. Works perfect! I get 25-30 psi underway.