63/64 MERC SIX 100HP LOSS OF RPM UNDER LOAD PROBLEM

[UnderPressureLLC]

im hoping someone can help me out. i have a 63/64 MERC INLINE SIX CYLIDNER 100HP engine. the boat runs fine and revs out fine and foward, neutral and reverse when hooked up to the hose out of the water. problem is when the boat is in the water, the boat will run fine and tach up like it should in reverse, but when you put it in forward and put load on the motor, at wide open throttle the motor doesnt tach beyond an estimated 2000 - 2500 rpm and doesnt go more than 5 mph. does anyone have any suggestions on what i can look for?<br /><br />thanks. reply here or email me at UnderPressureLLC@AOL.com or message me on AIM at screenname O3GSXR1OOO <br /><br />thanks.

 

[dennis1980]

Re: 63/64 MERC SIX 100HP LOSS OF RPM UNDER LOAD PROBLEM

i also have a 63 mercury but 65hp mine was doing the same and i changed the fuel to penzoil at 50:1 and changed the plugs it didnt have marine plugs in it if that dont work take out your adj needles and jets in the carbs count your turns though its worth a shot!!!

 

[JB]

Re: 63/64 MERC SIX 100HP LOSS OF RPM UNDER LOAD PROBLEM

Howdy, UP.<br /><br />Your engine is not running fine when not under load. <br /><br />You are not making power on all cylinders. Because it takes no power to run without a load it sounds fine, but isn't.<br /><br />Do a search for power loss under load. Bring a cup of coffee.<br /><br />Good luck.