View Full Version : How to run a compression check

10-09-2005, 07:40 AM
:) :)Hey how do you do a compression check on a 1985 Mercury 150 XR2 engine? Any help will be appreciated. I'm mechanically challenged. Thanks for your help.
Paul aka Survivor

10-09-2005, 09:00 AM
You will need to first get a compression gauge (I think Kragen has a loan a tool program). Then remove the spark plugs,if there is any danger of crossing wires remove one at a time, from the cylinder your wishing to test. If you are testing one at a time be sure to remove the coil wire so your engine can not start. Install the test gauge and crank the engine thru a crompression stroke, record your reading and move on to the remaining cylinders. I have a gauge your welcome to use if your near Penryn. Good luck.

10-09-2005, 09:46 AM
;D ;DThanks Digger, that's exactly what I needed to know. A fellow want a compression reading on a Ranger Bassboat I'm selling. Probably a good idea. The boat is starting to look pretty good to me now, all cleaned up and upgraded, I may just keep it.
Thanks again,
Paul aka Survivor

10-09-2005, 08:35 PM
hey survivor it should be done with a warm engine and let it go through 3 compression strokes (three pumps of the needle). let us know the results


10-10-2005, 07:00 AM
:)Thanks guys, I'll post the results for you, and let you know how long it takes me. I usual have to do everything at least 3 times to get it right, senior moments you know! So far in trying to trade or sell my Bass Masters Classic, I have fixed it up so well, I just may keep it now, it looks new and if the pressure check comes out good I may keep it or at the very least raise the price on it, lol. ;D ;D ;D
Paul aka Survivor

10-10-2005, 03:02 PM
;D ;DHere's the results, thanks to all the help on this board. I just posted the whole thing which includes the compression results. It's on the Boat Board ;D
Model 373V with 150HP Mercury XR2, oil injection, with a Quicksilver Laser SSTL 3 blade prop, with Ranger Trail trailer.
New Minn- Kota Maxxum 24 volt 74lb. Thrust foot control trolling motor
New Stoltz Ultimate bow stop
New X-125 Lowrance Fish Finders (2 each) on Johnny Ray removable swivel mounts
New Group 24 Everstart deep cycle batteries (2 each)
New Rodsaver retractable transom tie downs
New carpeting
New upholstery
Lowrance in dash temperature gauge
Hummingbird in dash flasher
Onboard Motorguide Max Pro 3 bank charger
Factory made removable front flipping deck

The boat has been checked out by C & C Marine and is in good shape. The whole boat looks new and would make anyone proud to own it. Check out the pictures, looks better in person.

Also I ran a compression check on all the cylinders and here are the results, starting with the top left cylinder and going down from left to right:
116+,118,116,115+,116 and 120. Excellent is between 120 & 125, 100 or lower is bad, so this engine checks out pretty good.

If you want to get into tournament fishing or serious bass fishing, at a great price, this is the boat for you. Asking $7900.00 OBO. Or would trade for a near equal smaller 16ft. to 17ft. bass boat plus or minus cash either way. This Ranger is too fast, too big, too much boat for me to handle comfortably alone. So if you have a bass boat with a 50HP to 90HP 2 or 4 stroke with V hull, of equal value or close, letís talk. Iím very flexible to trades. Email me for additional pictures or information. Thanks for looking!
Paul aka Survivor ;D :D :)