DT140 not running, getting spark n fuel

[qzone83]

I recently bought a pair of good running DT140s from a guy who was repowering. I installed them on my boat. One runs like a scalded dog. The other won't start. When I first got it installed, it fired over and ran for a couple seconds. Then shut off. Repeated once, and shut off. Then would just turn over but not kick off. Spray in the starting fluid, and it fires off.

So I'm getting spark

I swapped the fuel pump with the good one. Nothing. Swapped the injectors with the good ones. Nothing. Have verified that it's getting spark. It is getting fuel all the way to the injector rail. Just doesn't seem to be going into the cylinders.

So, any ideas?>>>>>>>>>>>???????????????????

[Solarman]

What year are the motors?
Are you using the parts off the good running motor to test the bad one? You did mention swapping fuel pump and fuel rail, or injectors?
Did you try swapping the computer, rectifier, and magneto too?

Post back, good luck.

[qzone83]

I have swapped out the injectors and both fuel pumps. Havent done the computer because it looks more involved than a quick swap, but that would probably be next. The fuel rail appears to be part of the intake so not sure I could swap anything there. Like I said, it's getting spark because it kicked off the one time naturally, and then everytime starting fluid is put to it. I just doesn't seem to be getting fuel into the cylinders. Is it possible the computer messed up just the injector commands and is still getting spark?

[qzone83]

Don't think I answered, the motors are 99 EFI. I just swapped the rectifiers to no avail. When I pull the plugs I can smell fuel on them, not really strong, but some. Had a mechanic look at it, he was stumped. He found the compression to be good, the injectors good and working properly. Said it's getting spark and has ample fuel pressure. Being that it has a fuel smell on the plugs I feel like maybe it isn't getting a strong enough spark. However, while messing with it, it did fire once, but that was it. I'm seriously lost.

[qzone83]

oh yeah, it has 36 lbs of fuel pressure to the fuel rail. I pulled the plugs and no mist came out as I cranked it. Is there something in the intake that could be blocking fuel from entering the cylinders?

[Solarman]

The injectors feed right into each cylinders intake where the reed valves are, and where it mixes with the oil to run the motor. If the injectors are not clogged, and if you have good compression, then you will have good suction on the intakes.

You don't need to keep spraying starting fluid into the throttle body. Starting fluid has no oil and it may wash oils off critical parts internally.

If the injectors are working and not clogged, then you should be getting fuel to the cylinders.

You should remove the hose at the bottom of the VST that supplies fuel to the high pressure pump. Inside that end of the hose is a small screen filter. Check to see if there is any debris (if yes, then identify what it is. This may tell us if something is blocking fuel flow.

Post back, and let us know if you find anything in the screen.

[qzone83]

New development

Well, I checked the filter but found nothing. However, I had some help over here last night and found a new development and did a little more research based on it. Found that while cylinders 1 and 3 have spark, 2 and 4 do not. Everything I find is that it is likely the computer. That's no fun. Hard to believe that it ran fine when I bought them (confirmed, I saw it) and then when I install them that the computer is bad. Going to check the magnets on the flywheel and all of the sensors first, plus the coils and such. Hopefully that will reveal a much cheaper fix. If not, then I will be swapping computers from the good engine to see if that fixes it. It is nice having two motors to compare Also going to hook up a brand new battery, because I read that a low or weak battery will cause the computer to do odd things.

Thought though. I would think and have experienced in the past, the motor should run, but not well, if I pull out the plugs from the 2 non firing cylinders. But it doesn't.

Any further ideas? fire away, because I'm just guessing at this point.

[Solarman]

You should look for damaged wires, bare or pinched, for the cylinders not firing. Also, check if you have a neutral shift sensor, that should be located on/ around the shift linkage, if your motor has one it may be affecting firing if not working?
You can swap good coils to see if That corrects firing to non firing cylinders.

Good luck, will think more on your problem.

[qzone83]

well I had an hour earlier to mess with it. Tried to start it in gear to see if anything changed. guess what, it turned over as it has been. My thoughts were that this should keep anything from happening, as it does on every other boat I've owned. So I moved on, now thinking I must have failed to hook something up or did it wrong. Still wanted to rule out other possibilities. I moved coil wires to what were supposed to be firing cylinders, but still nothing. I actually didnt find any of them to be firing. Guess thats what I get for taking the word of my 66 year old, non-mechanic, father. I checked out the flywheel and everything looks good. The tooth count sensor looks rusty on the back side, but so does the working one on the other motor.

Next direction is to try and track down this neutral safety switch. Maybe swap out the ignition switches and make sure theyre hooked up right. Thanks for all of the help. As I'm sure you can tell, I am determined.

[Solarman]

You should not be able to turn motor over, by starter if in gear. Check all wiring to make sure there aren't any bad connections.
That neutral safety switch should be in the control box. It should not allow the starter to crank the motor if control is in gear.

Good luck, post back.

[qzone83]

That's what I was thinking also. I tried it on the other motor as well and it would start too. Thinking I have something hooked up wrong on that.

Now, had a little bit of a breakthrough this morning. Also added to the confusion. I started swapping parts to see if the parts were bad. Started with the key switches, they're fine. Traced all the wiring in the console, appears fine. Next, I swapped spark plugs. They are all new plugs, as I replaced them when I bought the motor. After the plug swap, the motor fired up and ran rough for a couple seconds. Fired it up again and it smoothed out and ran about 5 seconds, then shut off. Wouldn't start again.

I swapped the coils on the motors, nothing. All parts once put on running motor, work just fine. So far the only part that is making a difference is the plugs. Thinking I got a bad batch of plugs, I put the "bad ones" in the good motor. It ran fine with the "bad plugs."

Is it possible that the motor just likes a different spark plug? Maybe these plugs aren't hot enough and that motor is fouling them for one reason or another. I want to say that the motors didn't have matching plugs when I got them, but I just looked up in the manual what they take and bought 8 of those, not what was in them before.

If this is the case, what plug could someone recommend to try?

[Solarman]

It is possible to get a bag plug from time to time, but stick to the recommended plugs.
From what you're saying, it sounds like you have a bag connector, or bad section of wire in those wires somewhere? You need to check the grounds and connectors. Also any pinched, damaged, or stiff wires (may have corrosion inside).

Post back if you find what it is, good luck.

[qzone83]

Well, got another hour today. put in a new battery, no change. Spun over way harder though. Verified that it was getting spark, certainly is, all four cylinders. As I was checking the spark it tried to kick on only cyl #1. Then added a second plug in hole #2. Kicked off a little better. Put the rest of the plugs in after verifying they were all sparking. Damn thing kicked over and ran for about 5 seconds. Had the wife hit the key again, fired and ran for about 45 seconds. Gave it just a little throttle, and it ran about 30 seconds. I repeated this for about 10 minutes (on the hose). The run time got shorter and shorter. Then started to backfire a tad bit. Got to where it would only fire once over. Then nothing after a backfire. Now its back to not running.

Probably forgot to mention. It is running on premix, but the oil injection still functions properly. Didn't make a difference on the other motor. But I think next chance I get, I will try fresh oil free gas out of a separate tank and see if that changes anything. And get some new plugs.

[Solarman]

Have you tried swapping the throttle body, as a complete unit? Just unbolt, disconnect hoses and plugconnector then swap?

Post back what happens, goods luck.

[qzone83]

I haven't. I'll get some time Tuesday to mess with it again. I'll try that.