Run away engine! pegged at 7,200 RPM

[SabrToothSqrl]

pulled my ski's out of the water last friday, after running a few hours. everything normal.

I went to 'blip' the engine to blow water out of the exhaust.

engine went right up to 7,000 RPM SCREAMING, I couldn't kill it! stop/start didn't work, fuel valve shut off, pulled the plug wires! I dumped water on the top of the engine to try to keep it from melting!

Finally got it killed w/the choke.

what happened?!

I removed the airbox, and my friend and i tightend the screws on the carbs,tested compression (good)

this is after a rebuild last year

now it appears to work correctly, and idles at 3500 RPM on trailer, approx 1200-1400 in water.

anyway, runaway engine with the plug wires removed is NOT fun.

thankfully it didn't happen ON the water. i'd have been F*CKED.

 

[Dr Honda]

First... it will never happen in the water, since that was a lean-run-away, and if there was a load on the engine, it would have died. If it was just a stuck carb... pulling the wires would have killed it. Make sure the manifold and carbs are tight, and that the gaskets haven't split... and then just turn up the low fuel needle about 1/16 of a turn. The extra fuel will keep the combustion cool, and won't allow it to "Diesel." Also... the proper way to kill it is with the choke, so if it happens again... just pull it.

 

[jhinson]

Mine did this, I over turned the low speed control and the motor filled with fuel. I had to take the plugs out to get the motor to crank thus blowing the fuel everywhere.

 

[6KJR]

Ya Im thinking a stuck throttle or it was really lean. Check it over good.

 

[jhjesse]

I'm thinking from your description, that the carb screws backed off creating an air leak between the carbs and intake causing the lean condition. Tightening the screws probably fixed the problem.

 

[SabrToothSqrl]

45 seconds at an uncontrolled 7,000 RPM on land without cooling sure felt like 45 minutes!

had it out again the other day, still runs fine, but I may tear it down this fall for something to do...