1999 Johnson 50 HP bogging above half throttle

[jrtax]

I have a 1999 johnson 50hp that i bought after it has been sitting for about a year. It would not hardly run and it was starving for gas so i cleaned the carbs and blew out fuel lines and it has been running great. I took it to the lake and it idles great and runs great at 1/4 throttle to maybe 1/2. When i go to about 1/2 throttle it starts to bog down. If i choke it is revs up like its suppose to but shortly after i let off the choke, it bogs back down. I can get it to run wide open by bumping the choke and it will run good without the choke for about 5 sec and then it will start bogging down. Does anyone have any idead what it could be. I pulled the carbs off and cleaned them pretty well. I didnt take out any jets or anything. Just cleaned the bowl and the inside. Its still doing the same thing. It seems like its getting plenty of gas to the bowl. I took each fuel line off and them done seem to be clogged. Does it seem like its starving for fuel or does it seem like its getting air in the line. Thanks for any help

 

[keykev]

Re: 1999 Johnson 50 HP bogging above half throttle

i would pull the carbs again but this time take out the jets and use mild carb cleaner and light compressed air to clean them out. chk. float levels and fuel filter. it sounds like its starving. hope this helps..............

 

[boobie]

Re: 1999 Johnson 50 HP bogging above half throttle

Get a small packing slip wire and run through high speed jets. And then stick a flashlite in the bowl and peer through the jet to make sure it's clean.

 

[5150abf]

Re: 1999 Johnson 50 HP bogging above half throttle

Yup, pretty clasic clogged high speed jets and as always boobie is right, you need to phsically clean the jets with a wire, I use a stripped stranded copper wire and just peel back wires till it just fits.

Clean all the jets like that, there are 3 of them, run the wire thorugh all the passages as best you can and blow it oput good with compressed air, the air in a can for somputers works good if you don't have a compressor.

As a tip, put a clean newspaper down to work on and do one carb at a time putting the jet cover with the jet so you don't get them mixxed up, you can imagine how I figured out that trick.

Also get at least an inline filter on it, a fuel water seperator if you want, I haven't had a single carb issue since I started running a fuel filter and I just use a $3 inline from Orielly.

 

[jrtax]

Re: 1999 Johnson 50 HP bogging above half throttle

thanks for all the help. I will do that. I know a guy that ownes a motorcycle shop and they have this ultra sonic cleaner thing that they use to clean carbs with. Do you think that would work or should i still take all the jets out and clean them. im not trying to take the easy way out , but from what he has told me it does a really good job. I just want to do what would be the best.

 

[boobie]

Re: 1999 Johnson 50 HP bogging above half throttle

Just remember, the easy way can turn into the hard way real fast.

 

[FredBear]

Re: 1999 Johnson 50 HP bogging above half throttle

I had the exact same problem with the same year and HP engine. I was told that if you aren't providing direct oil injection, the engine can get tricked into thinking it is being starved of oil. Apparently, there's a sensor of sorts that will tell the engine not to rev above a certain RPM, in my case it was around 2k I believe. Whomever ownded the boat before me disconnected the oil injection line and started pre-mixing the fuel.

I also had the carbs rebuilt, so I don't know which was the problem, but something for you to consider if you can't resolve the issue. Good luck!