Compression test on used RZ2

[BlueridgeLake]

I'm looking at a used RZ2 with 105 hours and I had them do a compression test and I'm trying to determine how concerned I need to be about the results? The boat has been sitting on the lot for a couple of months and the test was done cold. Here are the readings: Any insight is appreciated.

Bank 1 is Cyl 1,3,5,7
Bank 2 is Cyl 2,4,6,8

Bank 1
Cyl 1 was 190
Cyl 3 was 165
Cyl 5 was 195
Cyl 7 was 190

Bank 2
Cyl 2 was 200
Cyl 4 was 190
Cyl 6 was 170/175 almost to180
Cyl 8 was 200

[chpthril]

The rule of thumb is that the lowest should be within 10% of the highest. #3 is a little outside of that. Given that the engine hasnt been run and it was cold, Id be willing to bet those results would be different if the engine had been run and was warm. If you are having 2nd thoughts, ask the shop to do a leak-down on #3. This will give some indication as to why its low.

[Cloud]

Agree with Mike. Has to be done when the engine's warmed up. Numbers should be higher.

[WakerideN]

x3 mike is spot on.... on #3 along with testing and running it again after warm.

[BlueridgeLake]

Thanks for the help. I'm going to have them run the compression test again on a warm engine and then we'll see what we get.

[boatwakes]

Common issues with low and unmatched compression relate to the exhaust manifold to elbow gasket issues and are usually found in the two cylinders directly below the gasket joint. If there's still a discrepancy after the warm test, there will be, then remove the exhaust manifold from the cylinder head on that side and inspect the exhaust ports for rust which will indicate a leaky gasket which will then point to a valve job.

[rensink]

You could always have them perform a leak-down test if the numbers still questionable that would be able to give you a good idea as to what the problem is...

[BlueridgeLake]

Thanks for the responses, I had them do another compression test with a warm engine and all cylinders came back right at 200 so I pulled the trigger and will be the owner of a used RZ2 in a few weeks.

[TeamAllen]

Congratulations. That's AWESOME!!
Post up a few picks when you can.

[Timmy!]

Amazing what a warm engine with oil running through it is like compared to a cold one. Congrats! Make sure you give us some pics!

[robert theisen]

Make sure to post up some pictures. We love pictures!!!

[chpthril]

Congrats, glad it worked out