Johnson 115 Stalling issue experts needed!

[Captain Jeff]

1999 Johnson 115 OceanPro stalls in gear when you're giving it gas. It also stalls sometimes when it is just idling. It idles just under 1000 rpm. If you push in the key solenoid while accelerating it will run fine. Occasionally it will accelerate fine if you "gun" it from idle speed but will often start to accelerate and then stall. Finally you may get the boat to stay at say 1500-2000 rpm and be cruising along for a few minutes and it will then conk out due to lack of fuel.

I've come to the obvious conclusion this is a fuel starvation issue. I have spent a fair amount of time addressing this issue with basically no luck ahhhhhhh! Here is what I have done since the issue started last year:
-Rebuilt all 4 carbs (soaked, compressed air dried, Johnson kits)
-checked compression, all 4 cyls factory perfect
-replaced the fuel line from the tank to the engine and installed a new Johnson primer bulb and a water separating fuel filter.
-replaced the VRO unit (was mixing too much oil)
-de-carbonized
-new onboard fuel filter
-carbs are synchronized and timing is good
-new spark plugs
-new optical sensor
-new power pack
-new thermostats
-fresh gas
-plenty of fuel flow to engine and no air leaks, tank is vented

So what is wrong with my engine?!?!?!?! You must be a genious if you can figure it out. Thanks!

 

[mrcombel1963]

Re: Johnson 115 Stalling issue experts needed!

Not an expert here but I had the same problem and after the carbs were rebuilt most of my problems were gone, although some times after switching over fuel systems small peices of junk can get caught up in the carbs again sometimes you gonna do it a couple of times and hey it could be the fuel pump. I replaced the water seperator twice, had water in the tank. sounds like you've done alot, maybe you missed something uhhh??
Also buy a "Manual" if you have'nt already. Seloc has all the good ones. beats braking something if your wrong.
Stacks

 

[imported_lorin]

Re: Johnson 115 Stalling issue experts needed!

I don't know what is wrong with your motor but I can make a couple of suggestions. One is to get a pair of insulated pliers that are made for pulling off spark plug wires and pull and repalce the wires off one at a time as the motor runs. The rpm's should decrease as you pull each wire so if it doesnt decrease when you pull one wire you know that cylinder isnt contributing to the rpms so you have a problem on that cylinder. Another thing to do is put a timing light on each spark plug wire and watch the light to check if the spark is cutting out on any cylinder. Getting really deperate? Premix some gas with oil and put it in an oil squirt can. Pull off the air box. With engine running squirt gas into each carb and listen to hear if rpms increases. If it increases on one carb then you know that carb is being deprived of fuel. Finally, have you checked the fuel tank for water? I would drain the carbs and try running the motor off a 6 gallon tank which you know has clean fuel.

 

[OBJ]

Re: Johnson 115 Stalling issue experts needed!

I think the clue here is pushing in on the key while accelerating and she runs fine. Means your not getting the fuel flow you need...either to match the air flow through the carbs or not enough fuel at all. Recheck the link & sync. If OK, I would go back into the carbs and clean them again. Also recheck your fuel line connections...making sure they are tight.

Lorin has posted a good plan of action.....could help narrow down the problem.

 

[tashasdaddy]

Re: Johnson 115 Stalling issue experts needed!

totally agree with both above. i know it's extremely frustrating.

 

[Captain Jeff]

Re: Johnson 115 Stalling issue experts needed!

Thanks guys...I'll try this stuff out and let you know how it goes. I was also kinda thinking of adjusting the low speed jets on the carbs. I think they are the only jets that are actually adjustable. I figured they may be in too far, limiting fuel at low speeds because the engine runs great at higher speeds when it switches over to the high speed jets. Any ideas on this?

 

[Brew2]

Re: Johnson 115 Stalling issue experts needed!

Been chasing a similar problem for a long time and finally discovered the solution a few weeks ago.

Assuming you've gone through the fuel system to ensure no air leaks, you might want to increase the float height in your carbs ever so slightly.

In my case, my boat had quite a bit of bow rise which sloshed the fuel in the carb bowl away from the emulsion tube leading to the carb barrel. When I tried to accelerate, the motor would die from fuel starvation unless i circumvented the carbs by bumping the primer. While the manual says to set the carb float level even with the carb bowl when inverted, slightly more than that solved my problem.

I'd eliminate all the more typical problems first, gummed up carbs, air leak in fuel line connections, etc. If you are still having the problems, try some small adjustments to the carb floats.

Good luck!