Johnson 115 shuts down when pulling throttle back to idle.

[Rick88]

Hello all,

I am looking for some expert guidance and where better to look. This boat is a Stratos fish and ski with a Johnson 115, model J115PLEEM outboard. I am working on this boat for a friend and here is the deal. It starts and runs great, run it around for about 15 to 20 minutes and when the engine gets up to normal operating temperature, when you pull the throttle back to idle the engine shuts down. It does not do that when you first start it and run it down the lake, the engine has to get nice and warm apparently, but it does not do this on the muffs at all. You can restart the engine with ease, if you leave it in idle for several seconds it will die, if you try putting it in gear (forward or reverse), it will die, you can however, start it, put it in gear quickly but you have to go to full throttle basically and it will stay running. With the research I have done online, I am thinking I need to look at the ignition interrupter switch, where is it on this engine. He said he did have it at the shop not too long ago and they put on new coil packs, new plugs, new throttle cables and cleaned the carbs. I hope I have included all the info you guys may need to help guide me, if not, please respond and I will get the info to you

Thank you greatly,

Rick

 

[pn]

Re: Johnson 115 shuts down when pulling throttle back to idle.

yr, mdl. interrupter switches are for inboards. look up raising your idle speed.

 

[boony_124]

Re: Johnson 115 shuts down when pulling throttle back to idle.

Sounds like its running lean on the low speed idle screws. Try getting a tuning manual on your outboard and return your idle speed and low speed idle setting.

Test by running near full or full throttle for 1 minute then drop straight back to 700-800rpm. If it pops or stalls then slowly turn the low speed idle mixture screw anticlockwise 1/8 - 1/16 of a turn. Wait 15secs before each turn to wait for engine to adjust.

Then repeat. This is what I have done to a few smaller outboards. Only with single carbs. Worth a try.

Either that or there is an air leak/vacuum leak.

 

[metriccrescentwrench]

Re: Johnson 115 shuts down when pulling throttle back to idle.

yr, mdl.

He gave that ..... "J115PLEEM" - it's a 1999.

interrupter switches are for inboards.

NO, most V6 outboards have shift interrupt switches. But with that being said I don't believe they're on V4's.

look up raising your idle speed.

That could be. What's the idle speed with the boat floating free and the engine in gear? I only know the specs for the engines I have, but I'd guess it should be around 700 or 800 rpm. You'll raise the idle speed by advancing the idle timing just a hair.

Also, what do the plugs look like? If the engine used to run good but has started doing this recently it could just be time to replace the plugs.

 

[delfinasul]

Re: Johnson 115 shuts down when pulling throttle back to idle.

I was having some kind of problems with my 85hp v4 rude, the problem was the cables from timing plate (i don't know how is named that piece in your language so i'll try to explain what happened ). Normally when the throttle cable is moving the advance timing lever is moving with the carburetor lever, on my engine the advance timing lever first was stuck and released only at full throttle because the electrical cable insulation was hardened and some dust combined with the grease behind the flywheel.