89' Mercury 115. #3 cylinder no compression.HELP

2738 · #1 March 2nd, 2003, 05:29 PM

89' Mercury 115... Started running weird and finally did compression test. 1, 2, and 4 are between 110 and 120 psi. #3 appears nearly dead...barely registers on the meter.....Where do I start or am I completely screwed?

Any help would be greatly appreciated.

KIWI MERCMAN · #2 March 2nd, 2003, 05:35 PM

2738

Well if you want to look first you could pull off the exhaust covers and you will see in there, but if you have no comp then there is not much you can do from outside it. In your words I think your screwed.

Kiwi

NathanY · #3 March 2nd, 2003, 07:31 PM

I have some questions for you about your motor, please email me.

JB · #4 March 3rd, 2003, 02:36 AM

Hi, 2738.

It's a longshot, but try decarbing the engine and check again. You may have carboned up rings that are sticking.

Inspect the plug from #3. Metallic particles on it?

If those don't tell you anything, pull the head and visually inspect piston crown, head gasket and cylinder walls.

Let us know what you find.

Good luck.

dick · #5 March 3rd, 2003, 05:14 AM

Can't pull the head on those . Take off exhaust cover on port side and inspect sides of pistons and rings .Don't be supprized if you snap a few bolts . Take your time go slow and don't use a air impact gun.And if you don't allready got a manual get one.

2738 · #6 March 3rd, 2003, 05:23 AM

Thanks for all your help. Will try and pull exhaust plate this evening after work. Thanks again and wish me luck

bret walters · #7 March 3rd, 2003, 02:50 PM

engine is blown removing exhaust plate will only confirm this, spend your time removing power head.