shibaura s753 diesel engine won't start
I have a Multi-quip Diesel Light Tower. Basically a motor generator with a telescoping mast with 4 1000W lights at the top.
I bought the Light Tower from my Girl Friends son who runs several athletic fields for soccer. I help him maintain the towers. The one I bought was one he wanted to off load because it was hard to start and a rust bucket. The price seemed right, but I hadn't started it in months.
I towed it home (50 miles). Now at my house, I'm trying to start it and it won't start. I am fairly new to diesels, but I think I'm going after this the right way. Looking for tips:
Here is what I have done:
1. The injectors are mechanical. The engine turns over good, but I have had some other tower engines that seemed to turn over ok, but wouldn't start until I put a new battery in them to make them crank just a little faster. On this one I connected my battery booster so I think it is turning over fast enough.
2. These have safety cutouts for low oil pressure, high coolant temp, and low air flow. I assume that when any of these 3 things are out of spec. it cuts power to the fuel shut off solenoid. I checked power at the solenoid, and NO power. Eureka moment, but applying power directly didn't help in starting, but I believe it did bypass all the safety cutouts.
3. The fuel is pumped to the injector pump via a mechanical pump and there is a bulb squeeze type pump for bleeding air out of the system. I tried bleeding it, got fuel out the return line and a little out of each mechanical connection at the top of each injector. Didn't help.
4. I pulled the output line off the fuel pump and cranked it. Very little output, so I disconnected the in and out and put an electric fuel pump in it's place. I Bled the system with the electric pump at the top of each injector and the return line. I'm getting little to no fuel at the injector fittings.
5. Pulled the shut off solenoid and checked to make sure the plunger is pulling in, and it is.
6. So, here is where I am, It's 100 degrees outside, I have the electric fuel pump hooked up directly to the battery as is the fuel cut out solenoid. I crank the engine over and it spins nice, but doesn't even try to start. I run the glow plugs 30 seconds until the light goes out. I crack lose a connection to an injector and get little if any fuel.
7. I hope the following didn't screw something up. I pulled the discharge lines off of the injector pump and from the injectors. I cranked the engine, and only got a little squirt of fuel from one of the injector pump ports. My logic tells me that something is wrong with the injector pump, unless there is some kind of check valve that caps off the fuel flow when the fuel lines are disconnected.
I'm also wondering if the electric fuel pump is producing enough pressure. Could it be that the mechanical pump is shot, and the electric pump doesn't put enough pressure to the injector pump?
So, I need some advice, I'm really hoping it's not the injector pump, but it sure looks like it is. Oh, and then I thought, what if the engine is low on oil, thinking maybe the pump uses oil for hydraulics, but it's only down 1/2 quart. Any diesel pros out there?
Sorry for the super long post, and thanks for reading. Any help or suggestions will be greatly appreciated.
Last edited by paulcalif; 07-14-2018 at 04:27 PM.