35 hp johnson boging at wot ??

[poor man]

hi yall i have a 35hp johnson twin cylinder single carb, and it runs like a top at slow speeds and runs like a top at half throttle BUT after about 30 seconds(maybe) at full throttle it bogs down and stalls out, it will start right back up but will repeat itself over and over,,,

here is whats been done...

took carb apart and cleaned it with carb cleaner and air,

took carb apart second time and repeat step 1

took carb apart 3rd time soak it over night and blew out with air bought rebuild kit and replaced everything i could take off with new,

still stalls at wot after a few seconds


any ideas???? thanks

 

[lindy46]

Re: 35 hp johnson boging at wot ??

What year is the motor? Is it new to you? Have you checked compression? Does it have good spark in both cylinders?

 

[AlTn]

Re: 35 hp johnson boging at wot ??

at wot pump the primer bulb when it starts to stall...if it picks back up, your carb is being drained and you probably have a fuel side supply problem...fuel pump, lines leaking air, other restrictions...ie....just not enough fuel at wot

 

[poor man]

Re: 35 hp johnson boging at wot ??

What year is the motor? Is it new to you? Have you checked compression? Does it have good spark in both cylinders?

i think it was a 1979, yes new to me, yes compression is 118 & 120, 1plug was weaker than the other so i replaced them.

thanks

 

[poor man]

Re: 35 hp johnson boging at wot ??

at wot pump the primer bulb when it starts to stall...if it picks back up, your carb is being drained and you probably have a fuel side supply problem...fuel pump, lines leaking air, other restrictions...ie....just not enough fuel at wot

ok i tried that already and when it starts to bog down and i squeeze the bulb it actually will bog down more while im squeezing it, like its loading up ???


thanks

 

[zigzag]

Re: 35 hp johnson boging at wot ??

bet your pulling air into the lines somewhere. i don't have a lot of exp. to say for sure but i've been having the same kinda issues. try using a piece of clear vinyl tubing going into the carb to watch for bubbles. when you squeeze the bulb you just might be pushing a big pocket of air into the carb.

http://forums.iboats.com/showthread.php?t=419220

here's what i've been working on.....

 

[AlTn]

Re: 35 hp johnson boging at wot ??

ok...remove fp from engine leaving the "in" fuel line on and the carb side off...block the carb side outlet with your thumb and pump the primer bulb..any fuel leaking from the rear of the pump is probably being drawn into the crankcase causing the lower cylinder to flood...if nothing is noted, it's time to look at the spark with an air gap spark tester...advance, pep boys, az,o'reilleys...they all have'm....$10 or less...set it on 7/16"...test spark jump with plugs removed and grounded. < I use aligator clip jumper wires and ground to head>..the spark should jump that air gap and be blue in color

 

[poor man]

Re: 35 hp johnson boging at wot ??

ok...remove fp from engine leaving the "in" fuel line on and the carb side off...block the carb side outlet with your thumb and pump the primer bulb..any fuel leaking from the rear of the pump is probably being drawn into the crankcase causing the lower cylinder to flood...if nothing is noted, it's time to look at the spark with an air gap spark tester...advance, pep boys, az,o'reilleys...they all have'm....$10 or less...set it on 7/16"...test spark jump with plugs removed and grounded. < I use aligator clip jumper wires and ground to head>..the spark should jump that air gap and be blue in color

OK i did the fuel thing and no leaks, BUT i did notice that the primer bulb is bad because it lets the gas go back into the tank

thanks again