Runaway multifuel 6/20/14

Well my poor multifuel engine is toast - i'm pretty sure. Just took a little time today to put on the new hydraulic head that I purchased a few weeks ago. Finally got all the lines hooked up and went to test it. Started fine after several seconds and I get out to check for leaks. No problems so far, so I shut the truck down with the throttle kill knob. I decide to back it out of the barn to let it run longer and check things further. I start it back up. Starts fine and I hop out to open the barn door more and move some things. Engine speed starts to ramp up dramatically. Sounds a lot like a jet preparing for takeoff and black smoke is pouring out of the stack and quickly filling the entire barn despite two large doors being open. I quickly pulled the engine throttle kill and nothing happen. It didn't slow at all all and continued to rev higher and higher. I had read something about runaway engines when I was researching my hydraulic head issues, so I had removed the mushroom previously and placed a 6x6 block of wood nearby, just in case. I ran around the truck and placed the block over the intake and pushed hard. The engine would not stop. I ran around, jumped in the cab and tried to put the truck in gear and kill the engine - would not go in gear and black smoke was engulfing every inch of air. I run to the other side of the barn, open the door, pull out my skidsteer, and with a close by chain and a fair amount of foul language, I get the truck mostly out of the barn only to realize I had left the door open on the truck. So at this point thick black smoke is pouring out of the barn and I'm just thinking this thing is going to explode at any minute. Once the truck is outside and still billowing smoke, I drive the skid steer around to the side of the truck and attempt to apply more pressure to the wood block that is still being suctioned to the air intake. This helps a little, but not enough to stop the engine. The engine finally stops itself leaving a good bit of oil on the ground and there is only sizzling noises. As I'm looking over my truck in disbelief and disappointment, I hear sirens in the distance. It momentarily crosses my mind that someone has called the fire department because of all the black smoke. And sure enough, a couple of minutes later there are multiple fire trucks and an ambulance headed down my drive. Well, at least my neighbors are attentive. I found out a little while latter that they had tried calling me first but didn't even know if anyone was home and thought the barn was on fire. Not sure what I'm going to do now with the truck. It had always run so well. Anyone care to speculate on the cause of this particular event?

Nor familiar with your particular motor but I have had a V71 runaway. How did it stop? Was there any clanking noises? Have you dropped the pan and checked for debris? Don't assume it trashed - not yet.

Scary, hope the engine isn't blown.

Oh by the way, an easy to reach fuel shut off valve is a pretty good idea on a motor you are worried about running away. I found that out the hard way!

Nightmare!!! Do you think it was running at governed speed (2900) or way beyond?

You can usually stop a runaway by shooting a fire extinguisher down the intake. I hope you get lucky with your engine.

armytruck63 said:

You can usually stop a runaway by shooting a fire extinguisher down the intake. I hope you get lucky with your engine.

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CO2 only I assume.

If the fuel control linkage to the shut off valve came loose, it would do exactly what happened. How do I know? It happened to a friends deuce. I replaced the head on his truck but the little clip holding the rod to the linkage to the shut off came loose or I didn't get it on just right, and the truck ran away while he was out test driving it. It finally stopped on its own. The valves started floating and loosened enough to kill the engine. Since then the linkage has been reattached, and the valves reset, and have put 1200 hard miles on it with no trouble.

I wouldn't give up on her just yet. Not killing the truck blocking the air intake means you have a heck of a leak in your intake somewhere. There is a spot on the back of the can for the fording kit hose to supply the air compressor with air, but it is only 3/4 to an inch I believe.

If I were you I would take the shut off cover off and have a look. if the rod is loose you know that's what caused it. Then you can pull the valve covers and see what's what up there. Good luck and keep us posted.

There are two things with these trucks that scare the crap out of me and always make me mildly paranoid: 1. A runaway engine 2. The brakes failing. I hope the engine isn't damaged... Keep us in the loop.

Runaway does not necessarily mean that it is getting fuel from the fuel tank. It may be burning engine oil as fuel.

Yes, oil and air from the center bearing section of the turbo if that seal is compromised.

No, just kinda died out. but lots of oil on the ground. That can't be good.

It is pretty scary when it just keeps running faster and faster and nothing seems to stop it.

I ran in with some cutters to cut the fuel line, but the black smoke was just too overwhelming.

It sounded like way beyond to me. Pretty much like a fighter jet getting ready to launch from an aircraft carrier. The 6x6 block did calm it a little.

Keith_J said:

Yes, oil and air from the center bearing section of the turbo if that seal is compromised.

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Would there be a likely link to what I could have done replacing the HD?

armytruck63 said:

You can usually stop a runaway by shooting a fire extinguisher down the intake. I hope you get lucky with your engine.

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I read that tip afterwords. I did have a fire extinguisher handy and actually sprayed the engine after it stopped because I heard sizzling noise and the hood had slammed down when I pulled it out of the barn, so I couldn't see what was going on.

Sounds like the pawl on the lever shaft was not engaged in the slot on the control collar. This prevented free floating of the control collar so the governor could not control the engine, leading to full fuel when the lever moved the collar. I find a small mirror like a dental type is most effective to make certain the pawl properly engages the collar. Lubricating the pawl hole with a dab of grease keeps the pawl in position.
Did the control lever move freely before connecting the governor rod? It MUST be free, slapping from stop to stop.

Ferroequinologist said:

If the fuel control linkage to the shut off valve came loose, it would do exactly what happened. How do I know? It happened to a friends deuce. I replaced the head on his truck but the little clip holding the rod to the linkage to the shut off came loose or I didn't get it on just right, and the truck ran away while he was out test driving it. It finally stopped on its own. The valves started floating and loosened enough to kill the engine. Since then the linkage has been reattached, and the valves reset, and have put 1200 hard miles on it with no trouble.

I wouldn't give up on her just yet. Not killing the truck blocking the air intake means you have a heck of a leak in your intake somewhere. There is a spot on the back of the can for the fording kit hose to supply the air compressor with air, but it is only 3/4 to an inch I believe.

If I were you I would take the shut off cover off and have a look. if the rod is loose you know that's what caused it. Then you can pull the valve covers and see what's what up there. Good luck and keep us posted.

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That makes the most sense so far as I had to take that off to replace the seal on the little plunger thing. I sure hope it's like your friends, but all the oil worries me though.