Compression test results

[THall]

I did a compression test in the fall. It was my first attempt at doing it, so I'm hoping I did it correctly. I only did a dry test. The results were: #1-150, #2-130, #3-155, #4-135.

1. Should I be concerned about the variation?
2. If cause for concern, what action should I take?
3. Should I have disabled the fuel pump so it wasn't running while cranking?
4. If yes, what's the best way to do that?

Just for reference, you can see in these photos that the PO swapped out the FI for dual Weber ICT carbs. If you see anything else suspect in there let me know what you think. i.e. Is the routing of the fuel lines questionable?
gallery/image.php?album_id=20&image_id=29
gallery/image.php?album_id=20&image_id=30
gallery/image.php?album_id=20&image_id=31

Looking forward to eventually getting some education from Colin in person!!

Thanks for the help,

-Tim

[hambone]

Compression seems kinda high, but I'd not b worried too much about the variation.

[Amskeptic]

I did a compression test in the fall. It was my first attempt at doing it, so I'm hoping I did it correctly. I only did a dry test. The results were: #1-150, #2-130, #3-155, #4-135.

1. Should I be concerned about the variation?
2. If cause for concern, what action should I take?
3. Should I have disabled the fuel pump so it wasn't running while cranking?
4. If yes, what's the best way to do that?

Just for reference, you can see in these photos that the PO swapped out the FI for dual Weber ICT carbs. If you see anything else suspect in there let me know what you think. i.e. Is the routing of the fuel lines questionable?

When two adjacent cylinders share a particularly low reading, you might suspect an issue with the cylinder head machining. When two cylinders opposite each other share a low reading, you might suspect a cam lobe getting eaten down, as they share cam lobes. Your high readings may be because the engine was set up for higher compression or it is choking on carbon build-up. We can look down spark plug holes and get a visual on carbon.

The fuel lines are indeed as stupid looking as you feared. They also look huge. A tidy little s-bend run from one carb to the other, bisected in the middle for the tee to the pump, as far forward in the engine compartment as possible (i.e. near the fuel tank bulkhead so you don't overheat the fuel during hot summer day heat-soak) is good.

Some serious cleaning and detailing in there would be a good boost to the . . . zen.
Colin