1996 johnson 112 engine kicks out of high speed to idle

[woode]

Problem; 1996 Johnson 112hp, last time boat was out ran great for several minutes at speed. Then engine suddenly kicked out of high throttle and went to idle. Shifter/throttle lever remained in high speed positon. Problem got worse as the day went on. to no more than 15 seconds (at best). Engine is otherwise running great, no sputters, plenty of power when engaged, but just keeps kicking back to idle. Inpected lower end, no isusues, inspected console and linkage, no issues found. it seems to me as something electronically is kicking the throttle linkage on the carbs out. My manual is no help. I thought it may be a rev limiter, but my book doesnt say. Help...

 

[DJ]

Re: 1996 johnson 112 engine kicks out of high speed to idle

Is the linkage actually moving or does the engine just slow down?

 

[woode]

Re: 1996 johnson 112 engine kicks out of high speed to idle

Is the linkage actually moving or does the engine just slow down?

Lever on the console stays in the high speed position. unable to confirm whether the linkage at the carbs remains in the high throttle position at this time. Initially i thought the transmission was kicking to nuetral as well, but i now believe it was just the throttle. i know I need to take it out and do some more troubleshooting, problem is I have to take it 20 miles to launch, so i am trying to gain as much knowledge and build a big troubleshooting checklist of things to try and play with before i take it out again. Thanks for your reply.

 

[DJ]

Re: 1996 johnson 112 engine kicks out of high speed to idle

There is really no way the linkage, under the cowl, can move without corresponding linkage movement at the helm.

I think you are just losing power.

Do you have an inductive timing light? If so, take it with you. Hook it to one of the spark plug wires and run the engine. If you lose spark, on that plug, the light will not flash. Change the hook up to test all four.

Also, do you have a built in fuel tank? If so, run the engine with the fuel filler cap loose.

 

[emdsapmgr]

Re: 1996 johnson 112 engine kicks out of high speed to idle

You may be running out of fuel. The fuel pump may not be supplying the engine with enough fuel to run high rpm, but just enough to idle. Try squeezing the primer bulb when it slows to idle and see if the rpm's will pickup. Could also be a fuel restriction like a kinked hose, bad bulb, bad anti-siphon valve, no-vented tank, etc.

 

[tashasdaddy]

Re: 1996 johnson 112 engine kicks out of high speed to idle

is it running hot?

 

[woode]

Re: 1996 johnson 112 engine kicks out of high speed to idle

Thanks for the replies, some great ideas for me to checkout. I really hadn't given the fuel delivery much thought, as engine seems to run fine. When engine would "kickout" to idle it seems to idle fine, it did die a couple times but 9 out 10 it just went to idle. Fuel system sure could be a possibilty. I will add that a couple times,when I caught it dying and had a little throttle left to give, I pushed it all the way forward and it gave me like a 2 second surge of power and then went back to the idle mode (potential fuel problem).To anwser the question of engine temperature, I havent had any indications of high temp. My theory has been that a rev limiter is kicking out the throttle, but I now dont believe my engine has such a system, a few engine varients were listed in my manual, but not the 112. Also book doesn't explain how they work.
Once again appreciate all the response's. I definitly have some things to add to my checklist!

 

[woode]

Re: 1996 johnson 112 engine kicks out of high speed to idle

I still have not had it out in the water, to test some theories. Some honey-do's got in the way. Anyway, I was inspecting the throttle cable linkage (at engine) and have noted that. When the throttle is in the high speed position, I can with little force push the thottle linkage down towards lower throttle. Appears to be well over 1/2 inch of play in the cable. The throttle (at console) does not move much if any. I will add when I encountered the "Kick down to idle" I kept my hand on the throttle and kept applying pressure but to no avail. I may be on to something, but I find it hard to believe that the slack in the cable could be the only problem.

 

[Walker]

Re: 1996 johnson 112 engine kicks out of high speed to idle

Its not your linkage. Look at fuel supply as already mentioned.

 

[woode]

Re: 1996 johnson 112 engine kicks out of high speed to idle

Your Right! I was trying to pump some gas into a container to fill up the new water seperator filter. The bulb would not pump much gas. So I thought for sure the bulb was the problem. But when I went to the water seperator it was leaking. When I removed the filter there was a 3/4" slit (looks like the start of a hacksaw cut) close to the bottom edge of the filter, a little rust is also present. Gas freely flows out of it after i flaked the paint off with my fingernail. I guess those filters really should be replaced at least yearly. That one has been on 2 years. I do frequently drain the bowl. After replacing the filter, bulb quickly pumped gas. I will take it out next weekend for final verification. But I fully believe I can just enjoy a good day of fishing, without any problems. Thanks Guys!!!