8V92 Coughs but Won't Start (SOLVED!)

[wrenchturner6238]

I would be careful with the either . You want to make sure you can crank it all out meaning you have a full charge in your batteries that if it doesn't start on the either you can get rid of it. You don't want to either lock it. I am not there but it sounds a little slow on cranking speed in your clip. I would have my batteries nice and full and give the either a shot.

If you have a hand primer (for the fuel system )it would not hurt to make sure you are getting returns into the tank while priming .

 

[87cr250r]

Ether is mandatory to start Detroit 2-strokes in cold weather. They don't have glow plugs or grid heaters. Go ahead, do your worst.

Detroits have unit injectors and are fed by a voluminous gear pump. They self prime quite well.

 

[87cr250r]

I believe you. I was told this in regard to the many 4, 6, 8 and 12-71 series we ran. The explanation was the blowers lost the seals. But we didn't build our own blowers we swapped them. I never saw it happen. Cracked liners IIRC the most common problem. Probably got told some marine folklore there was a lot of that....

There is too much folklore around the Detroit engines. People think they'll run forever without maintenance but the truth is that they'll run until they die catastrophically. With our experience the 71 series generator sets got a major overhaul interval of 24k hours. The John Deere engines get overhauled at 35k. The 71 series Detroits have dry fit liners and if you run them too long they wear out the block so you can't in frame. Your Detroit is cheap to overhaul but it requires it regularly.

None of this is relevant to OP, however.

 

[hethead]

There is too much folklore around the Detroit engines. People think they'll run forever without maintenance but the truth is that they'll run until they die catastrophically. With our experience the 71 series generator sets got a major overhaul interval of 24k hours. The John Deere engines get overhauled at 35k. The 71 series Detroits have dry fit liners and if you run them too long they wear out the block so you can't in frame. Your Detroit is cheap to overhaul but it requires it regularly.

None of this is relevant to OP, however.

My dad ran a 6-71 in his truck in the early 70's. So did his buddy who bought one brand new and didn't believe in oil changes. He ran it for 500,000 miles then dropped the pan. Scraped out a gelatinous blob shaped like a crankshaft mold, put the pan back on, topped up the oil and ran it for another 500,000 before he sold it. Events like this certainly add to the folklore. I run a 6-71 (Gray Marine) in my landing craft and haven't touched anything on it besides topping up oil in 14 years. Zero. Runs perfect and starts in the 30's without ether. 92's I don't think are on the same reliability level as 71's and the 6's are the ones where they really did their homework.

 

[87cr250r]

The weakness of the 71 series are the dry fit liners. They frett and wear out the block. If you let this progress too long the block has to be bored for oversized liners which kills the ability to in-frame the engine.

 

[WillWagner]

Any progress on this? As others have stated, the smoke you have is telling you that the issue is most likely air driven. Blower quill shaft or intake flapper would be my guess.

Have you removed the air filter and had a look see?

After you stop cranking, there are no sounds like air trying to get in or out of the engine?

 

[matt2491]

We had a ton of rain yesterday going into today, so I couldn't really mess with it. I'm going to dive into it tomorrow.

I'll also charge the batteries to full.

I'm also wondering if it's worth installing a block heater? If so, I see a couple types available for 8V92. One installs in the water jacket access plate on the driver's side, and another installs in the NPT fitting on the side of the block on the pass side.

 

[87cr250r]

The block heater will certainly make it easier to start. I would do the plate style, get the heat where it needs to be in the head.

There are also silicone heater pads that you can stick to the oil pan. It won't help with starting much because the oil is so far from the block but it will help the starter spin the engine faster.

 

[silverstate55]

That little amount of smoke I saw is very light for that engine…it should be billowing a pretty thick cloud of unburned fuel. Check for the blower intake flapper; if you’re only seeing pipe plugs in the blower intake neck and no linkages sticking out, then there’s no shutoff flapper (none of the 8V92 HEMTT engines I have in crates have a flapper installed, but it doesn’t hurt to check).

Check on top of the governor for the air-powered shutoff solenoid; it should be retracted with no air pressure present and you should be able to rotate it about a quarter turn when retracted. If the shutoff solenoid is extended to rotate the shutoff lever with no air pressure present, then there’s your problem….fix or replace the shutoff solenoid.

You mentioned about 1/4-tank of fuel…can you see through the fuel or is it cloudy/obscured? Can you see the draw straw for fuel intake inside the tank to ensure it’s submerged in enough fuel and not obstructed? I ask because of the light amount of smoke in your video.

If there’s a vent on top of your fuel tank, replace it with an air fitting and using your air compressor pressurize the fuel tank to 5-10psi and hold that pressure for an hour or two; MAKE SURE YOUR THROTTLE LEVER ON GOVERNOR IS OPENED TO FULL THROTTLE FOR FULL FUEL (use a bungee cord to hold it open) AND MAKE SURE YOUR STOP LEVER IS NOT ENGAGED...you want to be able to have fuel travel throughout your fuel system and injectors and return back to the tank. Check for loose fuel fittings (they’re a PITA to reach around the coolant crossover pipe at front of engine), and check for wetness around fittings as well as along hoses to check for any potential leaks that will allow air to enter fuel system and lose your prime. It doesn’t take much of a hole for air to enter and you will not be able to maintain fuel prime.

For block heaters, I have trucks with both styles (driver’s side front of block and passenger’s side in oil cooler neck). Both work great with no issues so far. The style that enters the oil cooler is an aftermarket part, about half the cost of an OEM/NOS unit, but seems to work just as well for me in temps regularly down to 0-degrees here in winter. Alternatively, if you don’t have a means to engage your block heater, crank the engine for 15-20 seconds at a time (with a good 60-90 seconds between cranking) to warm up the cylinders, and it should fire after a few of these. Works for me, YMMV.

 

[silverstate55]

If none of that works, then it’s worth checking the blower drive shaft (quill shaft), accessible by removing cover plate on gear drive at back of engine. There’s a circular retaining ring (internal snap ring) that can be removed with needle-nose pliers in order to pull out drive shaft, just be sure not to drop it inside the gear case!!

 

[bigmike]

When you switch the engine off it activates a cylinder that shuts fuel off to the infectors. it’s on top of the motor by the box that houses the two rods that roll the racks. See that it opens and Closes when you switch on and off with the start switch. It could be a simple linkage fell off.

 

[matt2491]

Thanks so much for all the suggestions.

Check for the blower intake flapper; if you’re only seeing pipe plugs in the blower intake neck and no linkages sticking out, then there’s no shutoff flapper.

I'm only seeing pipe plugs, so I assume there is no flapper in there?

Driver side:


Pass side:

Check on top of the governor for the air-powered shutoff solenoid; it should be retracted with no air pressure present and you should be able to rotate it about a quarter turn when retracted.

Is this the solenoid? If so, it is fully retracted. I'm able to rotate the lever it's attached to a bit but against spring pressure.

You mentioned about 1/4-tank of fuel…can you see through the fuel or is it cloudy/obscured? Can you see the draw straw for fuel intake inside the tank to ensure it’s submerged in enough fuel and not obstructed?

The tank is about 1/3rd full. It does look like the tube is fully submerged. The fuel isn't clear, but it has always looked like this when I've looked in there.

If there’s a vent on top of your fuel tank, replace it with an air fitting and using your air compressor pressurize the fuel tank to 5-10psi and hold that pressure for an hour or two; MAKE SURE YOUR THROTTLE LEVER ON GOVERNOR IS OPENED TO FULL THROTTLE FOR FULL FUEL (use a bungee cord to hold it open)

I will try this. Is the throttle lever the same thing as the solenoid I posted a pic of above?

 

[matt2491]

Here are two more starting attempt videos:

Also, for what it's worth, when I take the air filters out and spray ether in for 2-3 seconds, the engine does fire right up for a second, but then dies.

 

[wrenchturner6238]

I still think you have some sort of fuel issue. If for some reason you have gotten an air bubble in you fuel . Your tank is low it might be that or there is air introduced from the lines. I would losen the filters to see if they are full. Then I would prime it up from the secondary filter forward leaving the primer hooked up if possible with a guage inline. And try starting the engine. If it starts good ; if not while the primer is still hooked up and crank the engine while pumping the primer

 

[87cr250r]

The unit injector Detroit Diesel engines are very good at self priming. I might be known for installing empty filters on an engine, starting it, letting it run to 1200 rpm, let the air bubble hit, and use the inertia of the generator set keep it going until the filters prime.

 

[wrenchturner6238]

With the lower temperatures should generate smoke and with the minimal smoke coming from the stack in his videos is why I think he has a fuel problem. If there was plenty of fuel in the engine when he hit it with either it should have went ahead and kept running on diesel or at least tried to

 

[G744]

Maybe check the fuel filters?

 

[silverstate55]

Thanks so much for all the suggestions.

I'm only seeing pipe plugs, so I assume there is no flapper in there?

Driver side:
View attachment 886594

Pass side:
View attachment 886595

**Does not appear to have a shutdown flapper installed**

Is this the solenoid? If so, it is fully retracted. I'm able to rotate the lever it's attached to a bit but against spring pressure.

View attachment 886596

View attachment 886598

**That is your Throttle Air Cylinder, controls your throttle lever. It rotates Counter-Clockwise to add more fuel and is closer to your driver’s side. The Engine Stop Solenoid is located on the other side of the governor (towards the passenger side) and controls the second lever on top of your governor cover...the Engine Stop lever rotates Clockwise to shut down the engine by killing the fuel supply. So, before priming, make sure the Engine Stop lever is retracted (you should be able to rotate it roughly 1/4-turn clockwise without air pressure) and use a bungee cord to hold the Throttle lever open in a counter-clockwise rotation for full fuel. Just be sure to remove the bungee cord before attempting to start!**

The tank is about 1/3rd full. It does look like the tube is fully submerged. The fuel isn't clear, but it has always looked like this when I've looked in there.

View attachment 886597

**Should be OK then, doesn’t appear to be algae or anything contaminating the fuel. Couldn’t hurt to add some fuel conditioner (anti-gel) as well as some Seafoam to keep your fuel healthy.**

I will try this. Is the throttle lever the same thing as the solenoid I posted a pic of above?

My replies are in yellow text below each pic.

G744 is correct about the fuel filters; when is the last time you’ve changed them?

Your videos still indicate to me that the engine isn’t getting fueled, and the little bit of white smoke is probably from the residual fuel residing in the fuel tubes and lines while attempting to start. You should get a LOT more white smoke from a properly-functioning fuel system when attempting to start cold.

Check your throttle and shut-down levers, then add 5-10psi of air pressure inside fuel tank while throttle lever is bungeed open for 1-2 hours….check for fuel leaks along the entire fuel delivery hose system. If nothing else, after 2 hours of positive pressure with throttle lever open, it should fire right up.

It almost seems as if the engine stop solenoid/lever is stuck in STOP (fully rotated clockwise).

 

[87cr250r]

I strongly disagree with the above post. Do not pressurize your fuel tank. The 92 series engines have unit injectors fed by a large gear pump. They don't have long high pressure fuel lines to trap air. The self-prime very well. The gear pump will also block flow from the tank when the engine is not turning.

Secondly, the injectors free-flow fuel in the shutdown position. Tying the throttle open means the spill ports will be closed in some injectors. It would be counterproductive to jack the rack in this case.

 

[BaconFarms]

If it runs on ether, its a fuel problem. Change and top off the filters. Check for green/gray slim. We just had a bacteria issue with our dozer. It's nasty and you should see it in the filler. They make an addative to eat/clean the bacteria. It takes a long time to get rid of it, probably a couple tanks full, so keep using the additive.

And, you fuel can gel at right around freezing, it don't need to be really cold. Throw some de-ice in the tank. Can't hurt.

And, you can run it for little bit longer on ether and see if it catches.

Fuel slime, it's real, LOL.