76 1150 Bogging Down

[JssCop]

the motor is a 1976 Mercury 1150 115 HP on a 15 ft. tri hull with a 19 pitch prop. With three adults pulling a tube the boat would take a little while to plane. With approximately six adults the motor would not hardly get over five miles per hour. I checked the spark plugs and they were black. Do the carbs possibly need adjusted? Any advice appreciated. Thank You

 

[Bob_VT]

Re: 76 1150 Bogging Down

Six adults in a 15 foot boat!! Wow! The boat is probably sitting so low in the water with 6 people I am not surprised. You were working that poor motor only because the hull was proably sitting deep in the water and it was trying to work. You loaded up the plugs.

What does the boat do when you are alone? I bet it will act better and the plugs will actually self clean when given a chance.

 

[Chris1956]

Re: 76 1150 Bogging Down

Jss, The combo should perform better that you described. It sounds like you are fouling some of the plugs. You need to try it at high speed with one person. First clean the plugs. Then if you can reach 5400+ RPM, the motor is likely sound and just misadjusted. d

The candidates for fouling plugs at idle speed are misadjusted carb idle mixture screw, carb floats out of spec, inlet needle/seat malfunction and leaky diaghram in the fuel pump.:'(

 

[timmathis]

Re: 76 1150 Bogging Down

Have you ran a compression check?

 

[JssCop]

Re: 76 1150 Bogging Down

yes but I cant remember the numbers but they were all around 140 - 145

 

[timmathis]

Re: 76 1150 Bogging Down

Did you try pumping the bulb at WOT. To see if it helped?
If not give it a try.
It will tell if it is the fuel pump.