50 hp johnson runs good for awhile

twc033

Cadet
Joined
Sep 16, 2003
Messages
9
my uncle has a 50hp johnson vro 1998 or 99 model. it will run smooth at 3200 rpms or less. it will run at full speed for awhile then it loses power and starts to buck and jump. when it starts to act up, you can idle it down, turn the key off, start it right back up, and it will run smooth at full speed for maybe two feet or two miles, then the same thing. did have water in the fuel, cleaned the tank and carbs, but problem still exist. no buzzers going off.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,746
Re: 50 hp johnson runs good for awhile

Could be a restriction in the fuel system. From the pick up tube in the gas tank, the line, the bulb, or a small chunk of something in the carb.
 

twc033

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Joined
Sep 16, 2003
Messages
9
Re: 50 hp johnson runs good for awhile

thanks roscoe,<br /> but i have replaced the bulb and line, cleaned and blew out the carbs and fuel tank and screen over fuel tank pick up. as i said it will run fine for awhile after turning the switch off. it like something is being reset when power is turned off. someone else mentioned a s.l.o.w. feature. any other ideas? thanks again.
 

ob

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Aug 16, 2002
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6,992
Re: 50 hp johnson runs good for awhile

twco33,When you say you cleaned the carbs ,does that mean that you dismantled the carbs and verified that there is absolutely nothing blocking any of the fixed orifices paying particular attention to the pickup tubes in the carb bowls?Compressed air will do little to dislodge any gummy deposits that may be restricting fuel flow.Had the engine set up for a time before this symptom surfaced?Reason being is that fouled carburetors is probably the most common ailment that affects two stroke outboards that have set out of use for a spell.
 

twc033

Cadet
Joined
Sep 16, 2003
Messages
9
Re: 50 hp johnson runs good for awhile

hey ob, <br />i did take the carbs all the way down. really like how the newer carbs have the removable tops so as you can see the high end holes. the carbs looked brand new, though there was some water in them. no gum whatsoever. motor was run one time this year without any problem. feel confident that carbs are not stopped up, though i did have that problem with the 1988 50 horse that i bought. thanks.
 
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