I have a 1989 mercury mariner 2 - 150 hp thats been sitting in garage since 1991 with maybe 30-50 hrs on it, motor looks brand new, when compression tested it red as follows,
from behind outboard all spark plugs removed, never been ran since 1991,
so outboard is cold
Left side top to bottom
right side top to bottom(starboard)
#4- 130 psi,
Is this normal for outboard under conditions listed above, or do I have to have it overhauled,or possibly do the repairs neseccary to fire it up (clean carbs, new impellor, new fuel pump) and possibly compression will even out after running it.
The gentlemen doing compression said he was a mechanic, there was no key so he used a jumper switch hooked up to the silinoid, did not ground the spark plug wires, is that ok beings (no key)
Last edited by mariog207; February 5th, 2008 at 11:42 PM.
Reason: read another post on compression with no lower unit attached
If you jump the solenoid with the key off, there is no spark, so no problem.
Sounds like there's something in #2, block of carbon, dead mouse, or whatever. Might need to take head off and clean, or might be able to de-carbon it. Worth a peak in the spark plug hole with a borescope.
I'd check it out if it were mine. I'd probably pull the carbs and reed plate off and check it all out. If you decide it will probably run, be sure go through the fuel system and put a fresh water pump in it before you try it. One partially plugged carb could grenade the motor before you get on plane.
Check out the lube in the LU also. Should go without saying.
If all that's too much bother, you can just give me the motor.
I just purchased a similar manual from email@example.com. $75.00 and well worth the info. Have your exact serial number ready and a credit card. Or you can buy a cheaper Seloc #1408 for around $35.
Check E-Bay, I got my Merc 1989 OEM there. I might have just been lucky when I was looking.
The Merc manual I bought on eBay for my 1988 XR4 was a rev or 2 back from what I would have gotten from Mercury. It was missing something, I think the XR4 gearcase. The OEM book is the bible, however, especially for timing, linkage, etc.
I can't afford the tools to get that serious on the gearcase anyway, and I highly trust my mechanic to do it right. It was, in fact, seriously messed up by the previous "mechanic" and Dan set it right before major damage was done.
All of the other mistakes made by this previous "mechanic" were easily fixed using the manual. They included Wrong reed/stop plate assembly, carb adjustments, linkage, timing, and fuel system parts. The worn out "old" motor really woke up.
Thanks for all your help and advice gentlemen, really helped out, Yea I think #2 has alot of cabon built in it, all 6 pistons show some kind of carbon deposits on them looks a little thick, and it was a moist looking deposit do to spraying liquid wrench in the ports, so I could rub a q-tip across them and see metal so hopefuuly it just needs to be fired up and decarbed and compression readings will even out, .(after all other steps are taken to run sleeping outboard).
Thanks again, and happy boating,