1996 evinrude 48 spl

[buzz6503]

engine idles finebut won,t throttle up. clean carbs, has fire to both plugs,any help? is there any way to check the diodes in the pack??

 

[JB]

Re: 1996 evinrude 48 spl

You have a bad carb, Chris.<br /><br />With it at idle, disable each plug. One will make no difference, the other will kill the engine.<br /><br />Overhaul the carb for the one that makes no difference.<br /><br />If you doubt my guess, spray some fuel mix into each carb. One (the good one) will choke the engine. The other (the bad carb) will raise the idle rpm.<br /><br />If that doesn't help, come back with more info.<br /><br />Good luck.

 

[buzz6503]

Re: 1996 evinrude 48 spl

well tried all of the above, sprayed carbs with throttle 1/4 open no change. won't go pass idle speed, pulled both plug wires[one at a time] no change. unplugged temp, sensor, started eng, same thing, plugged it back in, now is backfiring out the exaust.....could it be double firing? anything above idle is bumpty thump?

 

[JB]

Re: 1996 evinrude 48 spl

Hmmmm. I wonder if you have sheared the flywheel key and it has slipped into seriously retarded timing.<br /><br />It usually helps the helpers if you tell us everything rather than, "Yabut I did that" after we offer suggestions. Very frustrating.

 

[Silvertip]

Re: 1996 evinrude 48 spl

timer base link disconnected?

 

[buzz6503]

Re: 1996 evinrude 48 spl

ok. had this boat for three weeks, first weekend took it out, with five people in it, it would just get into plane eng would seem to go into slow mode, {thats what local marine mecanic called it} he told me to unplug the temp, sensor. oh also, same day unloaded everyone took it for a spin with just me in it, runs fine wot no prob, go back get ready to leave beach samething, right at plane eng begins to shutter the whole boat. now last sunday took a ride down river w/4 people in the boat, runs fine all day. pulled kids on ski's, no prob all day, headded back to ramp, about 2 miles primary tank had about 1/2 gallon of fuel in it, then it happened eng shuts down to an idle well i'm out of gas, i'm thinking. switch tanks, no change, changed plugs again still no change, have 3/4 inch arc at both plugs no melting under flywheel,, im lost..

 

[philobite]

Re: 1996 evinrude 48 spl

Chris,<br /><br />I had a similar experience when I first got my '87 48 SPL a few weeks back. It turned out that there were a few problems with the fuel supply that made it intermittently faulty like yours, esp off idle.<br /><br />First, there were two fuel bulbs in the line, and they were in the horizontal position, and they were in the 1st half of the fuel line close to the tank. I removed them and put one, where it belongs, back by the engine. I also made sure the fuel bulb has the exit side facing straight up at all times... they don't work well in any other position and can cause real intermittent problems as the valves open and shut with gravity.<br /><br />Second, one of the fuel bulbs had actually been put together incorrectly at the manufacturers (Wal-Mart purchase)! The exit valve was backwards and would not let fuel escape. So it would pump up hard, as if the line were charged with fuel, but only the pump was charged. Fixed that.<br /><br />Lastly, just for good measure, I put in a new fuel filter (which wasn't necessary but made me feel better).<br /><br />The motor behaves perfectly now, so if you've checked everything else it may be worth looking at the fuel delivery. Also, make sure your fuel tank vent is working and doesn't have a mud wasp nest plugging it.