1997 mercury 115 hp

[Johnson110]

The engine is surging at low speed, it will run smooth but then start to load up, I changed the water filter separator it seems to run better at high speeds before changing filter it would load up at high speeds too. When I replaced the filter I dumped it into a clear plastic container and it had white stuff in the gas, Plugs are not black fouled out. I am running a 6 gallon gas tank with a can of seafoam in it, the ran really good the first few times out but this year I have not really used the boat much so could this be a carburetor with crap in it? Like I said after chnging the water separator it runs fine a high speeds which it didn't before changing filter.

 

[QBhoy]

Hi. Is this a 2+2 engine. Think it might be at that age. Sorry to ask, but you’ll be aware of their character and their trademark behaviour? Either way, the fuel condition described isn’t good.

 

[flyingscott]

Be at what age? get fresh fuel in it and make sure the fuel lines are good.

 

[QBhoy]

Be at what age? get fresh fuel in it and make sure the fuel lines are good.

1997

 

[Johnson110]

Yes 2+2 motor and I understand how they run on 2 cylinders and then go to 4 cylinders. I changed the hoses this year they are the black fuel line hose not that gray hose stuff. The motor ran very good first few times out, it shakes at low speed (going in no wake zone) and then clears out smooth but back and forth smooth/ rough. Always ran quickleen and ethanol stabilizer in gas. Have some 16oz seafoam in 6 gallons of gas now. Is this fuel related or electrical problem? As I said the ran very good prior to this transition to 4 cylinders went smooth it idles very good too!

 

[Johnson110]

Took my sawzall and cut the top of the fuel water separator off did not see really any stuff in it. I know these motors I read about the stator going bad. Could the stator be causing the intermittent rough running at low speed?

 

[Texasmark]

I run with about 10* of positive tilt out (LU away from the boat) when running below 2k RPM. It's not rocket science for me. I can be in the no wake zone with the engine tucked in and notice the engine vibrating somewhat and all I do is trim the rear of the engine up slightly as mentioned above and it smoothes out. Also when I have done this when it's time to hammer down on it for the hole shot, it's clean, no initial stuttering for a few seconds....while the lower 2 plugs clean up. Everybody has their own way of running this engine. This is and a few other things are what works for me and it's one of the best engines I ever had...2002 model bought 2 years ago.

 

[Johnson110]

I run with about 10* of positive tilt out (LU away from the boat) when running below 2k RPM. It's not rocket science for me. I can be in the no wake zone with the engine tucked in and notice the engine vibrating somewhat and all I do is trim the rear of the engine up slightly as mentioned above and it smoothes out. Also when I have done this when it's time to hammer down on it for the hole shot, it's clean, no initial stuttering for a few seconds....while the lower 2 plugs clean up. Everybody has their own way of running this engine. This is and a few other things are what works for me and it's one of the best engines I ever had...2002 model bought 2 years ago.

Yes I do trim it up and seems to run a little better, It was running perfect before it started the shaking, running seafoam in gas now and will continue to see if it clears up. And yes I love the engine after I purchased the boat and motor I found out the way the engine is designed, same thing with this engine hammer down and transition is pretty smooth to 4 cylinders and it goes like hell !!