How to Measure Inlet Pressure Capability?

[ourkid2000]

Speaking of fittings, does anyone know of an easy way to measure the fuel pressure at the carb inlet?  Would be nice to find a tee made for this that had a male flare to the carb, a female flare to the hard line, and a tee to a barb for the pressure gauge.  The hard line between carb and pump makes it a pain to hook up a gauge.

Mike

How about you remove the hard line from your pump to the carb and then install both of those 3/8" barbed fittings you used to test the inlet needle seat pressure......one on the carb and the other on the pump. Then you can take a flexible 3/8 fuel hose and run that as your fuel supply temporarily.

Then you can cut the hose and slide the fitting from one of those cheap fuel pressure tester kits. See item #12 in my picture below. You can thread the fuel pressure tester onto that T-fitting and read it while the engine is running. Hope this helps!

[Shiny]

Thanks for the idea.  Yes, that will work...  maybe that kit even has a brass fitting to make it more direct?  I'll check the loan-a-tool at local parts store.

[ourkid2000]

Yes, possibly. That kit is only like 3 bucks on Amazon though.......you could even do the same thing with your vac/press gauge and a regular brass T-fitting and some hose clamps too.

[Shiny]

Yes, once I found the flare-to-barb adapters, the rest is easy.

As to $3 on Amazon, that's just wrong...

I paid $3 at Home Depot for a brass 1/8" male pipe plug today.  The world is messed up.

[Kenth]

That Amazon kit is for high pressure injektion measuring, not carb low fuel pressure.
https://www.amazon.com/gradora-0-140PSI-Injector-Injection-Pressure/dp/B09LCF2JGC/ref=sr_1_12_sspa?crid=VUZ4ASY2H9VQ&keywords=KIMISS+TU-114&qid=1677013616&sprefix=kimiss+tu-114%2Caps%2C654&sr=8-12-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzMFNYVkY2QTdKMkJKJmVuY3J5cHRlZElkPUEwMDk2Njc1MldLQkFTNkFFN05OQiZlbmNyeXB0ZWRBZElkPUEwNDkxODk1MllJMDVVQ0Y0STUyUyZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

This is a better option:
https://www.amazon.com/Performance-Tool-W80594-Vacuum-Tester/dp/B000FW2O1G/ref=sr_1_1?crid=PTT85Q8QVAK0&keywords=w80594&qid=1677014273&sprefix=w80594%2Caps%2C292&sr=8-1

Here are some fittings:

[ourkid2000]

Yes, once I found the flare-to-barb adapters, the rest is easy.

As to $3 on Amazon, that's just wrong...

I paid $3 at Home Depot for a brass 1/8" male pipe plug today.  The world is messed up.

Sorry, I meant 30 dollars, not 3 lol

[ourkid2000]

Hey Shiny,

I made this tool, for checking running fuel pressure, last week and thought of you. This was pretty easy and cheap to make and I think it's exactly what you're looking for. Using some of the fittings you showed me, I came up with this so you should be able to use the same ones you already have. I got the gauge off Amazon, it was also very cheap.

Cheers!

[Shiny]

Nicely done!  Thank you for sharing the pics.

I'm curious, does it bounce around at idle?  Does it smooth out at higher rpm to an average?

I had a hard time interpreting the "max" last time I measured.  I saw the gauge bouncing at idle and the "peaks" were high... too high, which is why I wanted to know how much the carb could tolerate.

[ourkid2000]

Yeah, it's fairly smooth with that liquid filled gauge. It's a smooth transition between 7-9 psi depending on throttle position with almost no bounce.

[Shiny]

Thanks

Maybe my gauge didn't damp well... I'll check.

And I like your brass tee fitting.  That looks like a good plan.

[ourkid2000]

Yeah I think the only tricky fitting there would be the inverted flare to 1/4" NPT fitting where the hard fuel line connects. I got mine from a local hydraulic supply shop. The rest was easy to find at the hardware store.