Runs great on muffs but not in lake

[Scott06]

I do not have an exhaust shutter valve on my exhaust pipe and when the issue occurred when I had it in the water the transom straps were off and I was even out in the middle of the lake when it died the only reason I'm thinking exhaust back pressure is because it runs fine on the muffs with no load obviously but idles and revs just fine as soon as you introduced water where it has the back pressure to overcome from the exhaust the engine struggles and dies in won't stay running

Take the drive off and see if the shutter ,which should be at the the top of the exhaust pipe just below the down elbow, is blocking flow. If it isnt stuck in there or in drive (it went somewhere) you dont have an issue with exhaust restriction.

 

[Rensch1983]

Take the drive off and see if the shutter ,which should be at the the top of the exhaust pipe just below the down elbow, is blocking flow. If it isnt stuck in there or in drive (it went somewhere) you dont have an issue with exhaust restriction.

Yeah that's a good suggestion I already had the drive off and the exhaust pipe flange it is a all clear

 

[Scott06]

Yeah that's a good suggestion I already had the drive off and the exhaust pipe flange it is a all clear

then it is no issue you have an issue making power which you wont notice on the hard because there is no load on the engine

 

[Rensch1983]

then it is no issue you have an issue making power which you wont notice on the hard because there is no load on the engine

Yup.. Just going to focus on Carb if fuel delivery from tank is ruled out.. Only thing it cab be at this point

Timing is set
Valves set
Motor is fresh
Cap/rotor wires look fine and pretty new

Just being how smooth and clean it runs on muffs it seems like it's got to be minor adjustments... I know no load but still if it was in left field it would stutter and spit and backfire even on muffs

 

[isaacs]

Could there be water in the bottom of your fuel tank that's making it's way to the fuel pickup when the boat sits at a different angle in the lake?

 

[Rensch1983]

I wouldn't rule it out at this point I'm going to change the water separator filter today and when I go back to the lake this weekend to try and tune it on the water I'm also going to bring a fuel jug from an outboard motor that I'm going to plumb directly to the fuel pump to rule out that possibility

Not trying to change too much at once so I will probably do the fuel tank first and see if it starts running a lot better then I know it's something before the fuel pump

If the fuel pressure is good and the fuel tank doesn't change anything I guess I can narrow it down to the carburetor as long as ignition is good which I think it is

 

[ROY WILLIAMS]

the ignition is working good .. but the fuel is dropping when the high power engine is not lean amount of fuel ..
filters ,fuel pump, gas tank vent clean ...

 

[Rensch1983]

Yeah I'll be back on water Thursday most likely so hope to get it sorted out