hf compression tester

[Karts of Kaos]

he guys so i finally broke down and got a compression tester but it isnt working right im not getting accurate readings on little engines like weedeater etc and on slightly larger ones im getting higher readings ones but still not accurate. im getting like 30psi on running 2strokes using the hose and 60 with the meatal peices with the rubber bit on the end. i think this is because of the hose volume. how do i resolve this?

 

[52Ford]

Sounds like either a faulty tester or you have a leak somewhere. I've always used one with a hose. Never had an issue.

 

[madprofessor]

Guessing you went $30 on this one below instead of $50 on their next level kit. I would have too, the $30 kit has plenty of adaptation.
Compression Test Kit 8 Pc. (harborfreight.com) ..................Sounds like you're snapping the metal extensions with the rubber cone stoppers on the end into the chuck of the gauge and getting the 60 psi pressing it into the spark plug hole while cranking (my past experience is like that), and............. you're snapping the hose into the chuck with a threaded spark plug adapter on the other end screwed into the spark plug hole for the 30 psi.
The way to know if there's a leak is to just see if it leaks down when you stop spinning the motor. Try it with both methods. I think the real key to either way is to get the motor spinning over as fast as you possibly can, something that working alone it'll be hard for you to do without an electric start. Doing it alone is where the plug adapters are needed, and you've got to get the O-ring to seal for it to work.

 

[Karts of Kaos]

well i was using a corded dewalt drill so they were spinning quick. i don think the pressure went dow at all but ill check

 

[52Ford]

Wait a minute... you shouldn't be able to see any leak down on a compression tester. Pressure goes into the gauge and is held there by a check valve. You need to push a button to bleed the pressure off.

I haven't used the HF gauge, so maybe it's different, but that's how all the compression testers Ive used work.

I was referring to a leak before the check valve.

 

[Karts of Kaos]

ahh ok