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1999 JOHNSON 150 HP ENG SURGING WOT

bass_ackwards

New member
"My boat/motor has been sittin

"My boat/motor has been sitting for 2 yrs. Emptied out all the old fuel, rebuilt carbs, changed fuel filter, added new in-line fuel filter in addition to one on motor, replaced spark plugs, checked for good spark, and performed compression check. All cyllinders were 105 psi or better (max of 115 psi).
Engine starts and runs fine, maybe a tad rough, idles at approx 1000 rpm, but when I go to WOT, when in the water, the motor died out repaetedly, but here in the driveway, the engine surges. Consistent power/loss/power/loss....driving me nuts. I've already replaced the squeeze bulb line from the fuel tank, nothing changed. Reset all the floats in the carbs to the same position when inverted, 12/16th" (book call for a range of 11/16"th to 1 1/8") still nothing is working. removed and cleaned what I believe are the low idle screws, and set them all to .590". Yet at full power, WOT, the motor still does the same thing surging from what sounds like full power, then dies off, over and over.
Any ideas?? If I can't figure this out soon, it's off to the shop for gos knows how long or how much!"
 
"try pumping the fuel bulb as

"try pumping the fuel bulb as the motor starts to surge, if it stabilizes it self it might be your fuel pump, it appears to me as if the motor is starving for fuel…"
 
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