Compression test question

[rgreenwell8962]

Hello all! Soon to be boating on a 2001 2500 SCR but am going to conduct a compression test prior to purchase. This boat has the Merc 5.7 Bravo 3. Just curious what results I should be looking for on a 600+ hour engine? Thanks for the info. I'll update my profile and give a better intro soon. I just found this site and it is a wealth of information! I look forward to chatting and meeting anyone that may be here in the Pac NW.

[seapuppy]

Rgreenwell8962
welcome to the zoo.....I live in the pacnorwest also and just came back from my boat...had to do some stuff too it and put some of our stuff we took off back on.....
compressions checks are done with all the plugs out......then with the gauge in the plug hole...hit the starter and turn it off till the gauge stops moving.....that's your highest compression....about 3 or 4 rotations of the engine....what your looking for is about 150psi (+/- 15 psi) ..all with 10% of each other....
I'm not positive at the max number of the cylinder since engines all vary ...what your looking for is a low reading which could be a problem with head or valves......600 hrs is about half life of a boating engine..what you really need to look at also is the manifolds/risers....those can be nasty if the PO didn't flush the engine after each and every use....

keep us informed...welcome to the zoo...and since I'm local...I can offer some help locally if needed...

SP

[seapuppy]

check your messages...I answered you...SP