85 johnson 115 stalls under load

[bajaboy]

low hours, had it since new. starts, idles and runs fine in neutral. put it in gear, revs fine until the boat planes. then it acts like it runs out of gas. restarts fine, but repeats the process. i've checked the tank, pickup and hoses. the tank was clean so i don't suspect gunk in the carbs. fuel pump maybe? or vro probs? how does the fuel system work?

 

[Yepblaze]

Re: 85 johnson 115 stalls under load

You have an idea what you need to do. You'lle need a manual that hopefully describes the areas you will need to look into. Also consider the de-carb treatments if it hasn't had them in the past. Although probably not related to your current issue.

 

[Brew]

Re: 85 johnson 115 stalls under load

Hi Baja,<br /><br />Unfortunately I don't have the answer for you, but I can co-miserate as I'm having a similar problem with my '86 140. <br /><br />So far I've cleaned carbs and put in carb kits, changed fuel filter, decarbed motor.<br /><br />Some things you might want to try to ensure that you are having a fuel problem would be to pump the fuel bulb as the motor starts to stall to see if it picks up again. If it does then I'd start by replacing the fuel filter. Failing that, there may be a valve gone kaput somewhere in the fuel line or your fuel pump isn't working to capacity.<br /><br />Another trick is to engage your choke as the problem happens, if it recovers it is definitely a fuel problem.<br /><br />If you do figure out what is going on with yours, please post an answer as it may help me with my motor.<br /><br />Thanks.

 

[clanton]

Re: 85 johnson 115 stalls under load

Check compressin, needs about 110 lbs, check spark, should jump a 7/16 gap, fuel pressure 3 lbs a idle, pump primer bulb while running. If problem clears, check fuel system with clear hose as close to fuel pump as you can get the hose, look for bubbles. Check vacuum on intake side of fuel pump , at full throttle in water in gear no more the 4 inches vacuum.

 

[DJ]

Re: 85 johnson 115 stalls under load

bajaboy,<br /><br />Does the primer bulb remain hard when this happens?<br /><br />My thoughts are; you haved a restriction someplace.<br /><br />I would be looking at the tank vent circuit-critters sometimes crawl into these. Also, some tanks have an anti siphon valve on the fuel line at the tank.<br /><br />To check, borrow a six gallon tank w/hose and see how it runs with that.

 

[bajaboy]

Re: 85 johnson 115 stalls under load

judging from the nasty stain that was left on my tow vehicle when i drained my boats tank into it, i am temporarily ruling out mech. failure. (ie fuel pump) and thinking that i had some bum gas and the carb jets are gummed up. the last time i had it out i did manage to get in a couple 100-yard sprints before it died, so i'm going to put some mobil 89 in it and try again today. i know "carb or injector" cleaner is a no-no, but can anyone recommend something to add to the gas- or spray up the carbs that might dissolve any varnish that may be up there?

 

[bajaboy]

Re: 85 johnson 115 stalls under load

brew! after a MONTH at the shop they finally got to it. turned out to be a hole in the fuel pump diaphram. good luck with yours