D722 hard start and heavy white smoke when running.

[dmax04]

I have a woods ztr mower with a D722 motor in it. manual fuel shut off. (cable driven)
It has ran great untell last saturday. I think i may have a problem with the injector pump.

lift pump seems to be working fine, when i take nuts off the injector lines fuel seems to just drip out. (when turning over) so i removed the injector pump and looked for anything out of place. all seemed fine. so i put the pump back in and turned it over. after some cranking it started. rpms went very high and smoked enough that i could not see the motor. so it seems to be getting fuel but way to much. Any help would be great. also this was using a inline filter and holding tank in air, using gravity to carry fuel to injector pump.

 

[meanjean]

I did a copy/save of this tip knowing it would come in handy:


Kubotas flow chart for probable cause for excessive white exhaust smoke covers the following:

-low compression pressure. cylinders must not exceed 10% difference between cylinders when testing compression
-water in the fuel or improper type of fuel. Drain and replace
-dirty or faulty injectors. Clean or replace
-faulty injection pump of valves incorrectly timed. Reset timing.
-restriction in air intake of exhaust system. Check and service.
-low operating temperature


Please describe the hard start.

 

[dmax04]

Running glowplugs then cranking for 30 seconds to one minute. It seems to build momentum. Then takes off. Would not start until I did the gravity feed. Bypassing the lift pump. It seems to run fine once its started but smokes very very much.

 

[dmax04]

How would I reset the timing? And I read on a different post that there are spring that could be disconnect?

 

[meanjean]

I'm not sure how to adjust the timing.
I would start with the easy things.
-drain and replace fuel.
-clean the air filter.

 

[dmax04]

Ok. I replaced the air filter. Fuel filter and all fuel lines. Still dealing with the same issues. It does start easyer. But once it starts it smoke like crazy. Any ideas?

 

[meanjean]

Glad to hear there is some progress.

Did you try new fuel?
Maybe you've got a jug of bad stuff.

Check the air filter housing.
Maybe there something clogging it between the filter and the engine.
Mouse nest?!

Try running a tin of carbuerator cleaner.
Worth the $5.

The notes I copied/pasted may have a typo:
-restriction in air intake of exhaust system. Check and service
Maybe it should read:
...or exhaust system.
Can you remove the muffler and try running?

 

[handyman]

Hate to say it but heavy white smoke sounds like head gasket to me. Better check compression on cylinders. Maybe someone else will jump in.handy

 

[dmax04]

Well I thought about the head gasket. And the oil is clean. Washed and dryed fuel tank put new fuel in. Help! Lol

 

[cmorningstar01]

With the engine running try loosening the injector fuel lines one at a time, Loosening just enough for some fuel to start weeping from the connection should cause that cylinder to start missing and the rpm's to drop, If you do not get a miss then that cylinder would be suspect, Run a compression test on all cylinders to determine that they are all within specs.

A head gasket can leak :

Cylinder to cylinder causing low compression in the 2 cylinders.

Oil to water ports causing oil to enter the cooling system.

Water to oil causing water to enter the oil system.

Cylinder to water causing water to enter combustion chamber

Cylinder to water causing excessive pressure in the cooling system

Cylinder to oil causing oil to enter combustion chamber

Cylinder to oil causing compression loss thru oil system

A combination of all of the above

If the compression test show low compression on a cylinder/s and the head gasket is eliminated as the cause then inspect valves/valve seats for wear,carbon deposits,cracks or burnt areas.

Check to make sure the Decompression knob/lever is not engaged and is working correctly

 

[dmax04]

When I start the Motor. I can't get it to shut off. So that makes me think there is somthing wrong between the mechanical shut off and the pump. ? And when it starts the rpms go very high, like its being over fueled and not being governed.

 

[Iraqmachinist7487]

I have a D722 that has the exact problems you are describing. Did you ever figure out what the problem was? I sent mine to a small engine shop and they told me the engine was wore out and needed rebuilding. It was running fine when it quit. What caused it to quit was the fuel pump went out. I replaced that and it had fuel to the injector pump, but would not start, so I took the injector pump apart and reassembled. It would start but smoked so bad you could not stay in the shop. It also ran wide open and you could not shut it off. The springs on the governor are good and attached. Getting ready to do a compression test. Any ideas?

 

[twomany]

Compression test is a good idea.

If the valves on one cylinder have gone south, loss of compression will send plumes of white smoke out the exhaust due to the unfired cylinder.

I had a SHOP RAG sucked in the inlet on the B7200 I bought (just to get the snow blower and box blade it came with)
Rag out, the darn thing has served me just fine for three years now.

 

[Iraqmachinist7487]

Compression test is a good idea.

If the valves on one cylinder have gone south, loss of compression will send plumes of white smoke out the exhaust due to the unfired cylinder.

I had a SHOP RAG sucked in tin.he inlet on the B7200 I bought (just to get the snow blower and box blade it came with)
Rag out, the darn thing has served me just fine for three years now.
[/kQUOTE] a chance to work on it aga
Thanks, I will run a compression test when I get a chance.