Compression ?'s

I hate to overload the Repair Forum with a bunch of questions, but I didn't want to ask them all in the same thread. So here goes another one.

I ordered a compression tester and it will be here in a couple of days.

1. What is the target PSI to look for?

2. Will it affect the test if my carb is not attached to the intake manifold?

3. What are some other things I need to consider to get an accurate compression reading?(I've never done this before)

If it makes any difference, I have a 78 Vespa Grande

Re: Compression ?'s

normally a compression test is done with the carb wide open. It will affect the pressure.

My a35 with an airsal kit is 160 psi, but I forgot to open the carb up.

Re: Compression ?'s

Well I guess it's not an immediate issue. I'm going to have to rebuild the carb and who knows how long that could take. I'm still waiting to hear back about the rebuild kit. Plus I'm having spark issues.

Re: Compression ?'s

George Smith /

lol compression also varies on engine type etc ive seen some 2 strokes with 150psi stock new, and some with as little as 60psi stock new alot of factors. :P so be model specific and not just go by 120psi like everyone says :P

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