1995 Merc 115 HP

[Kancel]

1995 18' Astro F&S w/ 115 Merc. Owned 2 years. Max speed 52MPH @ 5200 RPM. This year I seem to have lost 10 MPH and about 300 RPM. Max is now 42MPH @ 4750 RPM. Sea Foam in tank and new plugs, no help. Any help would be greatly appreciated.<br />Thanks,<br />Mike

 

[rickdb1boat]

Re: 1995 Merc 115 HP

First thing to do is head out to your nearest auto parts store and get a compression tester and check all the cylinders. They should be at least 100 PSI and all readings within 10 percent of each other. Then we can go from there..<br /><br /> Try to get a tester that screws into the spark plug holes, as opposed to the rubber ended type that you have to hold against the spark plug hole. Much easier and more accurate.

 

[Kancel]

Re: 1995 Merc 115 HP

Rick,<br />Thanks for your quick response, I appreciate it.<br />I checked the compression and from top to bottom on the 4 cylinders I get 155 on the first 3 and almost 150 on the bottom cylinder. I guess that's OK?<br />I also pulled the plug wires to check for spark and got good spark on all 4. I did, however get lit up. Shocked when I held the plug wires. Could they be the culprit? If so, any suggestions on where to get replacements? I'm fairly new at this, had the boat for 2 years, and I really appreciate all your help.<br />Thanks,<br />Mike