I just bought a 15' bass boat with a 1990 40hp elo engine. Oil injection has been removed.
Here's the list of stuff I've done or know:
Compression 110,110, 105, 110. Just power tuned with merc tune.
Poly gas tank was removed from boat, emptied, cleaned, filled with clean 50:1 gas
New fuel lines and bulb
Rebuilt fuel pump.
New float in one carb (fuel logged) both rebuilt with new gaskets. 1 1/2 turns out.
Carbs are wma7-1b and wma7-3b
Plugs are clean.
Stator ohm/dva tests fine.
New rectifier and charges perfect.
New impeller kit with excellent tell tail.
I was water testing with me in the boat. Topped out at 32ish mph gps. The motor starts perfect, idles perfect. Problem is that the hole shots were typically good and acceleration to wot was decent for a 40hp. Once at wot for approx 10-15 secs it would back off and I would loose about 7-8mph but would continue to run like that until I throttled down to idle. Choking the engine while at 25 caused it to run worse. I anticipated the engine running rich at that point so experimented with leaning mix screws as much as 1/2 turn in without much change. While idling back to ramp I could tell I was having a miss that I had not heard/felt while wot or running before that. Back at the house I had no spark on cylinder #1 with plugs out of engine but intermittent while installed. I have tracked it down to a faulty switch box and have one on order.
Here's a video of an acceleration towards the end of the "session" wot runs before this were smoother.... http://db.tt/hwJ0Ygxf
Any thoughts?
Thanks,
Adam
Here's the list of stuff I've done or know:
Compression 110,110, 105, 110. Just power tuned with merc tune.
Poly gas tank was removed from boat, emptied, cleaned, filled with clean 50:1 gas
New fuel lines and bulb
Rebuilt fuel pump.
New float in one carb (fuel logged) both rebuilt with new gaskets. 1 1/2 turns out.
Carbs are wma7-1b and wma7-3b
Plugs are clean.
Stator ohm/dva tests fine.
New rectifier and charges perfect.
New impeller kit with excellent tell tail.
I was water testing with me in the boat. Topped out at 32ish mph gps. The motor starts perfect, idles perfect. Problem is that the hole shots were typically good and acceleration to wot was decent for a 40hp. Once at wot for approx 10-15 secs it would back off and I would loose about 7-8mph but would continue to run like that until I throttled down to idle. Choking the engine while at 25 caused it to run worse. I anticipated the engine running rich at that point so experimented with leaning mix screws as much as 1/2 turn in without much change. While idling back to ramp I could tell I was having a miss that I had not heard/felt while wot or running before that. Back at the house I had no spark on cylinder #1 with plugs out of engine but intermittent while installed. I have tracked it down to a faulty switch box and have one on order.
Here's a video of an acceleration towards the end of the "session" wot runs before this were smoother.... http://db.tt/hwJ0Ygxf
Any thoughts?
Thanks,
Adam