Fuel pressure test port, 1995 Merc 502 EFI

[thunder550]

I am looking at installing a fuel pressure gauge on my 1995 502 Mag EFI. Where is the correct location to install the sender? Does anyone know the thread size?

 

[alldodge]

Being a 1995 you should have a VST and a shrader valve is on the front of the fuel rail (item 22)
http://www.mercruiserparts.com/bam/subassembly/31902/1614/140

In the link above it also shows a filter (item 10) and you may or may not have this, it depends on your serial number.

But back to your question. You can install a gauge on the valve or remove the valve and install a Tee fitting, to reinstall the valve and your sender

 

[thunder550]

Thanks for the link!

Serial 0F593768, looks like it's this one without the filter instead:
http://www.mercruiserparts.com/bam/subassembly/31796/1614/150

Same part number for the valve and cap.


Any recommendation on whether to keep the valve in place with the tee, or just replace it? I'm wanting to install a gauge in the dash (have an extra hole to fill up there) with an electric sender.

 

[alldodge]

Test your pressure with a mechanical gauge using the shrader vale. Then remove the valve and install your gauge. This way you have a reference as to how accurate it is

 

[thunder550]

Great advice, thanks for the help.

 

[Bt Doctur]

Why would you even consider running a fuel line under 41 psi thru the boat to the dash gauge ?

Simply put a fake gauge in the hole.

 

[thunder550]

Why would you even consider running a fuel line under 41 psi thru the boat to the dash gauge ?

Simply put a fake gauge in the hole.

I wouldn't. You missed the part where I specified that it's a gauge with an electric sender attached to the fuel rail. No fuel lines to run anywhere, it's not a mechanical gauge.

Here's a link to the gauge, it's even designed for marine applications...

http://www.autometer.com/2-1-16-fuel-pressure-0-100-psi-marine-carbon-fiber.html

 

[thunder550]

Oh, and if you squint your eyes just right and ignore the chrome bezel, it even almost matches my factory gauges :lol:

 

[Bt Doctur]

a Sharpie will take care of the shine, Have never seen a Shrader to 1/8 or 1/4 pipe fitting so you may have to cannibilize a rail gauge just for the hose fitting.

 

[thunder550]

Well the plan was to remove the schrader fitting from the fuel rail completely and get an adapter from whatever size the threads are in the fuel rail to 1/8" NPT. I took a look at the schrader valve location today though and I don't think that I really want to mess with it. Looks like it might be a PITA to get the fitting out without removing the intake manifold, and I don't want to go through the effort to do that. Cancelled my order for the fuel pressure gauge, back to square one. Will just leave the dead gauge in the extra hole until something else comes along. I thought about just adding a clock but the cheapest one I found that will fit is $75, I don't want to know the time that badly...