Detroit Runaways And How To Prevent One

Quick video showing the common reason why a Detroit can run away. The newer spring racks pretty much solved the run away issues, so engines with spring racks normally don't have emergency shut down flaps. Before I start a Detroit that has sat for a year or more I always pull the valve cover to confirm the rack is free.

[chrisseger]

I've said it before and I'll say it again... Detroits don't run away, the mechanics do. Awesome video as usual. Love the builds and knowledge I gain from em. Smart man, you are.

[adamolczak]

Last week, My Dad unknowingly bump-started a recently acquired 671 powered dump truck that had been sitting for 10 years. By some miracle, it just sat there and idled perfectly while running on the decade old fuel in the tanks.
I was horrified when he told me later in the day that he had it running, and fortunately this video existed to better explain my reaction.

[leroygreen]

I wish i had that flapper valve for my wife!! Her injector is stuck wide open!!!!

[beaverdam]

I just bought a aluminum 353 an that's the first thing I done was pull the valve cover had stuck injectors I love Detroit's an I enjoy your videos keep them coming

[erikturner]

Finally got around to watching this! Very helpful, thank you. My 4-53t has been sitting for about 6 yrs now....I will heed your advice!

[ChiefL]

Excellent & Very Important Video to SAVE especially with all the people that are buying these old buses to restore and know nothing about what they have and especially when they don’t have access to a quality mechanic like you and some others here on YouTube.

Great Job!

[UQRXD]

A generator on a Tugboat I crewed on had a 6-71 generator. The engine was changed out and the new one ran away on start up. Air intake never shut finally the windings in the generator rotor were thrown out and jammed it to a stop. Was most exciting sparks and all.

[dangoldbach]

A CO2 fire extinguisher is a very good idea with a Detroit. I have two Detroits, a 6v53 and a 6v92T, the 53 absolutely had stuck injectors and I knew it so I pulled the valve covers and worked the rack until they were free. Luckily I didn't have a runaway but that CO2 bottle was always within reach. The 92T is a fire pump engine rated at 496 HP, you better believe I have that bottle right up my ass whenever I fire it up! Haven't had to use it yet, but, better safe than sorry

[squirrelchaser]

You are so awesome. I am trying to start up my hatteras and this is critical info. I got lucky on starboard but your 1-2 year and could have been stuck note is key. I know how to block intakes but thank you because i will do more diagnostics now and i will have this thing ready and it is going to save me $ if i need oversight. Your rock. Thank you

[Caje-zfmd]

I have a 1960's inline 6-71 DD that I run twice a year. The flapper was rust-welded open and the cable leading into the cab did nothing. I removed the blower cover and had heat applied to free up the flapper shaft. The return springs on the shaft were also shot but the shaft/flappers are now freed up. My mentor attached a new cable to the shaft and ran it back into the cab where it can be pulled in case of an emergency. I hear a lot of grumblings about Detroits not having power but for an engine that was in production for 60 years, I'd say that that was a successful design.

[trevorgottschalk]

Good knowledge video
I started my 6-71 yesterday in my L9000 ford and it went from 0 to a billion RPM in 1 second. I just had it running two weeks ago. Wish i knew what happened. Glad my blow flapper worked. Still have manure running down my leg. Wow was that noisy and smokey.
Never dreamed this world happen

[paulnolan]

Never had a runaway, I used to work on 8&12v71 and 92 series Detroit’s years ago. I can’t believe how dry that 6v looks, start with the Governor Housing because the Fork in their can freeze then go down through both Links to the injector Tubes then check the “spring “ in the Injector Rack For return movement. A good oiling usually works most of the time and finally, the kill flap on top of the Blower Housing has a Pawl mechanism with a Bowden Cable attached, check the mechanism hasn’t stuck tight, again, a bit of oil usually does the trick. Finally, run the Engine and check it stops then restart and let it scream!- you’ve just reached Detroit heaven!

[captnemo]

I own a large boat with two 4-71s, in Oct the raw water heat exchangers get winterized, in April/May I open the raw water seacocks and start them both up after setting 7 mos. One such Spring start-up I was in the engine room crouched between the engines, hit the start button on one and it took off screaming. My first thought, closing the fuel line valve would stop it, no that didn't work, it began sucking fuel up through the return line without a shut-off valve. Final thought, nervously fumbling to get the air cleaner off, but having nothing within reach to block the air intake I pulled my T-shirt off, rolled it into a tight ball and held it over the opening, that suffocating the engine until it stopped. Yes, later found that one injector held the rack open at full throttle. A scary situation, but alone crouched next to a runaway was the worst. No I didn't run away, just got to it.

[wildcoastadventures]

Thanks for this valuable lesson. I have an 8V-71 sitting for 5 years I'm needing to fire up soon.

[tttco]

This is a great video. Thanks for the video. My 453 had a stuck rack when I bought it.

[jmyers]

i had one runaway but i was ready for it. always check the rack of any engine not run in the last year.

[mysticridgedesign]

Helps lots I am bringing a 318 back and was going to start it this weekend. Until now haha I will be doing a bit more before I push the go button. Thanks!

[edwardglamuzina]

I just seen your channel and your video on preventing runaway. I am now a subscriber. Have you ever have a 671 run backwards? In 1972 one of my first jobs I was dumping dirt in the fill and as I pulled forward I stalled the engine. I pushed the clutch in real fast and it came back to life only it sounded really bad and exhaust smoke was pouring out of the airbox . It was sucking air through the exhaust . I shut off the fuel and the starter got things spinning right again. It did scare the heck out of me but I knew what happened. I had a Sachs 2 stroke
dirt bike do the same thing in 1971. But at 15 yrs. old I was worried I hurt the bosses truck. Turned out that the truck was fine and I never had it happen again.

[Hitman-dsei]

Just before you go cranking a detroit that's been sitting for a while and you have verified the racks move, prime fuel system with a good pump, an old pump off the blower run on a drill or unbolt yours and put drill on and check return fuel into bucket, the injectors need to be full of fuel before you start actuating them by cranking over motor as they are a unit injector and are lubricated by the fuel or you may end up with a stuck one later on, the other thing is only non turbo motors have a flap, no matter which engine you have always have a CO2 fire extinguisher right there as it will stop any diesel motor if discharged into intake, never try to block intake on turbo 2stroke detroit to stop it, as they have different blower seals and can be turned inside out and allow oil and air into blower thru shaft area and then you cannot stop it unless you have CO2 so have CO2 every time you go to start an unknown engine

[donniebagwell]

Great explanation, best sounding engine