Pressure test fuel supply

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KenOlvis

Well-Known Member
Joined
Oct 10, 2014
Messages
1,228
If some one was to pressure test the fuel supply from tune pipe line to fuel line to carb what would be a safe limit of pressure to test?

Also how much pressure on average dose

.12 - .91 produce.

Dose somesone make a tool to test with before I make one up to check my fuel supplys in my boats

Can it be as simple as a fitting attached to fuel line an plug off other end an watch a gauge so see if it leaks down an if it dose it would help to find a weak spot.

Maybe use parts of blood pressure reader.

DRV2WIN

Ken
 
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Not "Rocket Science" here.

Simple thing that has worked for me.

Plug off the fuel line going to carb

pull pressure line at pipe

blow into the pressure line by mouth

pinch off pressure line, hold closed for a count of 20, let it loose. if air comes out. it's holding pressure

if not, you have a leak
 
What about removing the carb line. plug it then use a vacuum gauge to test. Like a brake bleeder.
 
What about removing the carb line. plug it then use a vacuum gauge to test. Like a brake bleeder.
JamesThank you for your suggestion.I thought of that also but I want to apply pressure my reason for that is what the system is under Im thinking the lines may seal under vacume not showing a problem as easy.

DRV2WIN

Ken
 
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Not "Rocket Science" here.

Simple thing that has worked for me.

Plug off the fuel line going to carb

pull pressure line at pipe

blow into the pressure line by mouth

pinch off pressure line, hold closed for a count of 20, let it loose. if air comes out. it's holding pressure

if not, you have a leak
If that works for you coolbeans do you use a Boris meter to help set carb or do you blow on line an listen it can work both blowing by mouth not as accurate.lol
 
I use a bicycle air pump to pressure check for air leaks,,,,,i also pressure ckeck my tunnel hulls for water leaks....bob
 
Ken,

I see your point. I like the bicycle pump idea if it has a gauge on it. Check with both vacuum and pressure to look for leaks at connections as well as possible pin holes.
 
A MityVac or similar automotive vacuum/pressure hand pump with a gauge will give you accurate low pressures or vacuum to test our fuel systems. The little pumps for checking the needle & seat pop off settings on Walbro carbs in our our gas boats can be used, also. Not sure how well they hold pressure, as they are made to check pop off setting not leaks.

Just looked at Amazon & Harbor Freight, $35-$40 for a MityVac
 
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I've used this and the soapy water method that does not lie . If you have a leak , soapy water will show it while pressurizing the line by moth .
 
The soapy water method is also what many tire shops use to find that persistant little leak. A low pressure pump would be helpful in this case as it will let you check out the system more thoroughly
 
Not "Rocket Science" here.

Simple thing that has worked for me.

Plug off the fuel line going to carb

pull pressure line at pipe

blow into the pressure line by mouth

pinch off pressure line, hold closed for a count of 20, let it loose. if air comes out. it's holding pressure

if not, you have a leak
If that works for you coolbeans do you use a Boris meter to help set carb or do you blow on line an listen it can work both blowing by mouth not as accurate.lol
Never use a flow meter, never saw the need in it
 
Not "Rocket Science" here.

Simple thing that has worked for me.

Plug off the fuel line going to carb

pull pressure line at pipe

blow into the pressure line by mouth

pinch off pressure line, hold closed for a count of 20, let it loose. if air comes out. it's holding pressure

if not, you have a leak
If that works for you coolbeans do you use a Boris meter to help set carb or do you blow on line an listen it can work both blowing by mouth not as accurate.lol
Never use a flow meter, never saw the need in it
Coolbeans sir

No problem soap method works fine I have used it my self just thinking of making a way to check it before using the soap

Thxs

Ken
 
Ken,

Get yourself an OS or YS engine check-valve. Put the check valve on your exahust inlet to the tank, fill it with some air/fuel, or whatever to pressurize the tank, plug the fuel outlet onto the other side of the check-valve (make a closed loop). Let it sit. If it doesn't hiss when you unplug the check-valve, you have a leak! Soap can tell you where the next time you run the experiment.

Cheers!

-Joey

Edit: If I recall correctly, the YS check-valve is 12-14 psi. I don't have any documentation to back that up, that's just what I seem to recall. So, yeah...not worth much.
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My YS 91 heli motor when I tested it 4 different times always read 4 lbs of pressure in the tank. Using factory YS check valve also from engine case to fuel tank.
 
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