1989 48hp SPL Evinrude Runaway/Stuck Throttle

[danielcascone]

I'm new to the forum so sorry in advance for poor post edict....

Model Number: E48ESLCER

I have a unique problem that i'm having trouble solving. I have a 1989 48 hp Evinrude that has a "runaway" throttle problem. When I hook the motor up to muff's and start the engine it won't catch on its own without a little squirt of carb cleaner (assuming I need to tear the carbs down and give them a good cleaning), the real problem starts when I raise the throttle NOT IN GEAR. The throttle gets stuck revved all the way up and won't back down. To get it stuck I need to raise the throttle all the way and keep in there for a few seconds, again this is not in gear just with muffs on.

The RPM's get stuck MAXED out and won't back down even after I take the throttle down and the kill switch won't even turn the motor off. To get it to back off I need to manually flip the linkage on the carburetors (the two throttle plates that are connected and on a "roller type assembly") essentially choking the motor and knocking it back down to idle. The kill switch works fine when the motor isn't stuck at high RPM's and i'm assuming the two are linked.

I have done this sequence while watching the linkage on the carbs and nothing is getting stuck or hung up, I even did it with the cover off the carbs and watched the "lollipops" inside the carbs return to normal position but the engine still get's stuck!!

Someone help i'm running out of ideas! Thanks!!

 

[Cofe]

Re: 1989 48hp SPL Evinrude Runaway/Stuck Throttle

Welcome to iboats!
With the motor off, disconnect the remote throttle linkage at the motor. Manually actuate the throttle linkage at the motor and find out where it is binding up. The throttle should return to idle position. Never use carb cleaner, or either to start a 2 cycle motor. You can mix up a spray bottle of 50/1 mix and spray it in the carb if needed.
A kill switch will not work on a thermal runaway motor. Even pulling the plug wires won't help. Thermal runaways can abruptly damage, or blow up a motor. Find out where your linkage is sticking with the motor off.

 

[danielcascone]

Re: 1989 48hp SPL Evinrude Runaway/Stuck Throttle

Mixing up a 50/1 as we speak! Yeah I figured that the kill switch wouldn't work because of the runaway problem. The issue is there is no place where the linkage is getting stuck or binding, everything seems to return back to its starting position but the engine remains stuck at its highest RPM. I'll inspect closer and try to find anything binding up but could it be anything else? My thoughts were an issue with the carb, I bought rebuild kits for them and i'm gonna soak'em and hit them with an air compressor anyway.

Thanks for the help and welcoming me to iBoats, this forum is an amazing help and has saved me time and money already!

 

[danielcascone]

Re: 1989 48hp SPL Evinrude Runaway/Stuck Throttle

Finially got my new impeller and after installing it I ran the engine, got it stuck on high rev outta gear then pulled the plugs. She kept on screamin so that means it must be a thermal runaway. Gotta say i didn't expect it to actually be the case but here we are. I'll run some stuff through it and take care of the carbon. Thursday is test run day!!!!

Thanks for help

 

[Cofe]

Re: 1989 48hp SPL Evinrude Runaway/Stuck Throttle

Dan, You really need to fix this problem with the runaway. With the throttle all the way down, the carb butterflies need to be closed.
When you pump the bulb, does gas come out the front of the carb with the motor off. If this is the case, your float in the carb is stuck open.
You may need to take it to a mechanic to make sure all the linkage parts are there. Having a runaway motor while on the lake can be a scary, dangerous situation.

 

[Roderick819]

Hi
Did you ever figure out the solution mine does the exact same thing.

 

[GA_Boater]

Hi
Did you ever figure out the solution mine does the exact same thing.

Start a new thread with your questions. The OP won't be back to answer you because he hasn't been in over three years. Look at the Help Tips on top of the page.