I'm working on a mid 90s Dynapac walk behind double drum roller. Has a hatz e780 single cyl diesel. The engine start easy with no smoke, but will not hold an idle, and has no throttle response what so ever. Will slowly rev up and down and eventually die. With no smoke. I suspect a rod knock but am not familiar with this machine so I'm not sure how knocky they are supposed to be.. Would a loose rod cause this strange throttle control or should I be digging into the fuel system? The filters are clean and the fuel is new. Any ideas? Also who's good for parts? Thanks for any help! Chris
I worked on a job with a similar roller, that Hatz engine sounds like it's coming apart the whole time it's running. It sure sounds like you have a fueling issue. I don't know the particulars of this engine but I would start with the tank pickup tube and work toward the injector pump and try to find a blockage or vacuum leak. Sometimes these manufacturers put a screen filter where you'd least suspect and they can become blocked. A fatigue crack in a steel fuel line from vibration would cause the engine to starve for fuel as well.
It's probably 25 years since I looked at one of these but I'll have a go.. When you say it starts ok, is that when you pull up on the excess fuel knob on the pump? If so I'd say you're looking at perhaps something broken or come adrift in the governor area. Take the fuel pump out and see if the governor lever makes the pump control fork move as it should. They're actually a neat little unit what with their auto decompressor and everything. They do have quite a pronounced diesel knock though. Also that's possibly the only 4 stroke engine you'll ever come across where the camshaft turns at 1/4 crank speed.
No glow plugs, decomp, or extra fuel to start I just turn the key, pops right off. Sounds great for 3 seconds or so then starts acting up.
Which fuel filters does this machine have? Some of these have a filter in the fuel tank. Have you checked for this? Where the hose connects to the tank, is there a square plate held on with 4 screws. If so, remove the plate to find a filter. If you're convinced you have good fuel supply then I'd still be looking at the governor. Can you post a photo?
Anything in particular you're curious about? The filter in the tank was replaced, and so were the fuel lines. I'll take the pump off tomorrow and see if there's anything obvious.. Thanks for your help, hope the thing is just noisy and has a fuel problem...
The machine we used had a hand crank to start it, what a bitch that was on a cold morning!! These machines are characteristically loud. What you think is a rod knock is more then likely the injectors being low on fuel. My truck does the same thing.