1995-1996 Evinrude 150 Intruder challenge!

[Chinatown317]

Not sure how to do this w/o telling all details
95-96 Intruder 150
Ran rough when i first purchased the boat, 88 Bumble Bee V178
New gas, new trim blinker
Had to adjust the motor height on the jack plate, got it to plane off and ride smooth
Top speed 50 mph
Then, near top end, bogs out 2-3 trips in a row
Then, runs perfect for a 15 mile trip. Runs great back to the ramp.
Next trip, bogs out at 40 mph, loses horsepower.
Mechanics suggest new fuel line bc the primer bulb was collapsing! New fuel line installed from the tank to the motor.
Fuel filter cleaned
Next trip, bogs out same. 40 mph, loses power. Roughly same amount of gas in the tank every trip. Did try running w the gas cap off, same result of bogging out!
Replace Champion spark plugs w new Champion spark plugs, QL78YC
Checked compression in all cylinders, 100-115 psi
Rebuilt all 6 carbs, gaskets and floats/pin
Took the boat out today, 50% quieter...... soooo pleasant!
Gas'd on, planed off nicely, ran to 42 mph, 10 seconds or so in, bogged out exactly the same way as it has in the past!
I can run it half throttle about 25 mph and it runs smoothly but after that, she is sickly!

Any and all info or suggestions are much appreciated!

 

[faztbullet]

did the bulb stop collapsing after changing line?

 

[Chinatown317]

Yes.... and then i added an electric fuel pump! Sorry, i left that out!
I will see if i can edit original post!

 

[Chinatown317]

did the bulb stop collapsing after changing line?

The run after the line replacement was fine or better. Then the next run was same symptoms! Mechanic suggested a electric fuel pump. Installed and zero changes!

 

[faztbullet]

Hold the key in when it bogs

 

[Chinatown317]

Hold the key in when it bogs

Tried that too w no luck. No change when i done that

 

[faztbullet]

Are the high speed jets tight?

 

[Chinatown317]

Are the high speed jets tight?

Yes, carbs were rebuilt/went thru a few days ago w new spark plugs

 

[racerone]

When you push the key in , a running motor should respond by slowing down.----Need to investigate why your motor is not responding here.

 

[faztbullet]

Need to check fuel pressure as suspect you have a VRO acting up or VST cover has a air leak

 

[Chinatown317]

Need to check fuel pressure as suspect you have a VRO acting up or VST cover has a air leak

Let me start here, this is my first boat! I am fairly mechanically inclined. I am learning everything as i go to do w this boat motor. With that being said, how do you check fuel pressure? And what does the VST cover look like? I just took the whole fuel assembly off the motor 5 mins ago to inspect all diaphrams n seals. It looks so new and clean as if it was recently rebuilt/redone.

Thank you guys for helping/aiding.....

This boat runs and rides so nice, when its running well, i dont wanna move onto another one!

 

[Chinatown317]

I have taken the vro fuel pump off to rebuild. It looks fine. No signs of wore out or bad seals or diaphrams. Any specifics to look for?