Need some options on 100 HP Mercury

[Hunka]

I had my boat up in Canada a couple of weeks ago and my 1991 100 hp Mercury ran a bit sluggish. I took it to a mechanic for a compression check and I have on cylinder that is too low. The #2 cylinder was at 105 while the others were in the 130's. I had them put some "mechanic in a can" in and it raised the compression on #2, but also on the other cylinders as well. They suggested replacing the rings on cylinder #2. The guy also told me that the spark plug in cylinder #3 was as clean as a brand new one, so he suggested putting in a carburator kit, which is taking place right now. I just had this motor rebuilt in 2002 by a different mechanic. Do I have any recourse with the previous mechanic who rebuilt the motor? I am a weekend fisherman and have barely 75 hours on the motor since the rebuild and I am not hard on the motor, I have put nothing but mecury brand oil in everytime I fill it with gas, the oil is topped off.

 

[WillyBWright]

Re: Need some options on 100 HP Mercury

Welcome to iboats.<br /><br />If your carb plugged, the earlier shop is off the hook. 2 years ago? Just rering the bad cylinder? I suppose, but the rings in there are two years old and not terribly expensive. Is your mechanic sure the problem was carburetion and not ignition? Sorry for the misfortune. Once the mechanic tears into it, there'll be more indications what went wrong.<br /><br />#2 is the carb I'd rebuild. #2 cylinder is weak, possibly from lack of lubrication. If the carb is plugged, it won't get lubrication. #3 I'd suspect lack of spark, but if one carb has goo... #3 compression is good, so it's getting lubrication. Clean as new is the clue here. Even a cylinder with a restricted carb fires once in awhile. That leaves traces of carbon.

 

[Hunka]

Re: Need some options on 100 HP Mercury

Thanks Willy, <br /><br />The carb kit should be finished later this week, hopefully, I'll find out more. <br /><br />Great forum.