johnson 115hp slows down at full throttle

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skip15
Posts: 22
Joined: Tue Dec 27, 2016 6:14 pm

johnson 115hp slows down at full throttle

#1 Post by skip15 » Wed Jun 21, 2017 1:01 pm

ok after spending $1800 dollars at a shoppe i took my boat out ran good went to put in full throttle ran good for about 5 min and then it started to slow down until it stopped brought back the throttle and then slowly brought it to full again and rani good but seemed to not have the power it had just before this happen like 3/4 throttle but kept running any suggestions don't want to bring back to shop he charges me $500 everytime i bring it back

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NonHyphenAmerican
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Location: South Central Kansas in Hooterville

Re: johnson 115hp slows down at full throttle

#2 Post by NonHyphenAmerican » Wed Jun 21, 2017 1:22 pm

[quote="skip15"]ok after spending $1800 dollars at a shoppe i took my boat out ran good went to put in full throttle ran good for about 5 min and then it started to slow down until it stopped brought back the throttle and then slowly brought it to full again and rani good but seemed to not have the power it had just before this happen like 3/4 throttle but kept running any suggestions don't want to bring back to shop he charges me $500 everytime i bring it back[/quote]


Check that fuel tank is vented.

Check that fuel line isn't collapsing.

Check that fuel bulb is pumped up solid and holding.


True Story.

I had a Honda 7.5hp outboard for my 14' shallow V boat.
Get it out on a rescue during a time when the river is flooded to get an elderly lady to dry land so she can go for dialysis.
Motor bogs down and quits in mid stream.
This gets a bit hairy with a swift current.
I look down and realize that the fuel tank cap isn't opened up to vent.
Open it and the tank sucks in air.
Pump up the bulb, pull the starter rope....Vrooom.
Pick up the little old lady, take her to safety, nice and dry.

Sometimes, it's the simple things so check the simple things.
[color=#FF0000][b]22' G3 SunCatcher V22F
Yamaha F-90
Tooning on El Dorado Reservoir[/b][/color]

illinoid
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Re: johnson 115hp slows down at full throttle

#3 Post by illinoid » Wed Jun 21, 2017 4:44 pm

I would bet it is constriction fuel supply. Mine did the same thing ad I found a small piece of plastic (California this may cause cancer label from 2 stroke oil bottle) that was getting sucked up against the fuel inlet in the tank. I cleaned it all out then had the problem again...collapsed fuel line caused by earlier problem...new fuel line and it ran great. I could tell I was having a problem with inlet because squeeze ball collapsed.
[color=#FF0000]SOLD[/color]1975 24 ft Kayot, 1980 70hp Johnson formerly "Joy Toy", now named "Waterlogged" Sold
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2 60's 17ft Richline canoes Sold one

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ralph
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Re: johnson 115hp slows down at full throttle

#4 Post by ralph » Thu Jun 22, 2017 1:32 am

Did they change the power pack?
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Bryden24shp
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Re: johnson 115hp slows down at full throttle

#5 Post by Bryden24shp » Thu Jun 22, 2017 3:03 am

X3 on the fuel issue! You aren't using ethanol are you? Fuel primer bulb and fuel hose killer!
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skip15
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Joined: Tue Dec 27, 2016 6:14 pm

Re: johnson 115hp slows down at full throttle

#6 Post by skip15 » Mon Jun 26, 2017 9:42 am

does have some ethanol in the gas

b52thomas
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Joined: Tue Jun 09, 2015 2:48 pm

Re: johnson 115hp slows down at full throttle

#7 Post by b52thomas » Tue Jul 18, 2017 5:29 pm

My 2001 Johnson 115 hp had the similar issue. Dealer found that the VRO Pump was bad and there was no oil being pumped at WOT. Told that I could have burned up the motor. They also replaced the power pack and the water pump and head gasket. $2133 later. Motor running strong now. Not sure I like parts replacers.... but it works well

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