Re: '84 Evinrude 115hp Loss of Power
OK, so I was out again this weekend, in relatively heavy seas (2-3 foot rollers and some chop on top with the occaisional 5 footer). The engine performed fine at about 2700 RPM, maintaining a 7-8 MPH pace (per my GPS) into the waves and wind, riding nicely over and through the waves. When I got into the lee of a peninsula I got the speed up to 27-30 MPH at around 4500 RPM. All good so far, right?
I should mention that I fueled with fresh gas from a gas station while the boat was on the trailer (16 gals in a 35+ gallon tank). I also warmed the engine up at no wake speed for about 10 minutes, after idling at the dock for about 3 minutes.
I turned to head back with the now following sea. "Surfed" one or two rollers nicely and maintained 8-10 MPH for a few minutes. Opened up the throttle and began to climb to 20+ MPH. The engine would essentially die. Thrust would be dropping and eventually almost die completely. I had to move the control back to neutral and then forward to regain any speed. Just advancing the throttle when power began to drop did no good. If I move the control to idle the engine died completely.
I suspect one of two culprits (or both). 1st thought is the fuel system/line. I was "jumping" off the tops of some waves and landing in the trough pretty hard. The power issue developed after/when I was doing this (though it did not occur when I was heading into the waves, only in the following sea). I checked the bulb on my fuel line when I was losing power and it was "soft". I squeezed it until it was "hard", assuming that fuel was not reaching the motor. Generally I was squeezing the bulb after the power loss issue occurred but i did try it once or twice while the motor was losing power and saw no improvement.
My second suspect is the throttle itself. It is an OMC and I presume original equipment (1989 boat, 1989 Evinrude 140hp). The throttle is a bit quirky in that it seems like it jumps the power from 2500 RPMs to 4500 with very little travel. Part of the jump could be the boat moving up on plane with that little bit of extra power and so RPMS jump because of less resistance. I even when I get up to speed (say 28-30 MPH and try to eas back just a bit on the control to see if I can get to say 15 MPH the motor slows considerably and I drop off plane to 10 MPH or less, again with only minimal travel of the shift. Further, the control arm "pops out" from the mount to put the motor in neutral so that it can be revved or started in fast idle. The prior owner explained to me that once the motor has been running it can be difficult to start in neutral without "popping" the arm out to full neutral position, shifted all the way (to both forward and reverse) and then placed in idle or fast idle postion for starting.
I am thinking that I need to monkey around with (or replace) the control and/or the fuel line.
Any thoughts any one?