Water in diesel?

[arnaud]

Hi everyone.
My first 2 rides with the overhauled engine were a moderate succes. At first it was holding back a lot, after a while it ran normal.
I guessed it was water, so i took off the feul line and the paper fuel filter, the latter indeed holding some water drops.
Also i tapped some fuel from the tank, about half a litre, but did not see water sinking on the bottom.
should i have waited longer so the water had a chance to accumulate at the bottom? or would it be noticeable right away..
I am asking this because yesterday i was full of convindence.
I started the engine and the idle was good, as before, but when asking some power, it started holding back again..
so i took out the water, and runnig got worse.. I did not get the chance of running it warm because it shut down, after every restart.
I was quite upset, this is the first time the diesel let me down..
When holding in, white smoke(damp?) was emerging.. not all the time though..
What to do?
is there an additive which might solve this?
Since i am reluctat to remove the injector because of the gaskets, do i need to when water is in it or will this be pushed out..

Or, did i screw something else up what might cause this?

[IgorVigor]

firstly, try it without the fuel filter...

if the filter paper is worn out, it wont allow enough fuel through...

as for white smoke from the exhaust, it is probably condensation in the pipe...

if you still think there is water in the diesel, a method I was told by an old farmer, who had a diesel tractor that had a small hole in the fuel tank that let water in...
he said that he would top the tank almost to the brim with diesel and then pour in about 5~10% of the tanks capacity with pure methanol as it absorbs the water...

he had a 20L tank on his small tractor and put in 1L of methanol usually...
it always ran well so I presume it worked...

just for the record though, I havent ever personally had a problem so I dont know if it will damage a small engine...

[arnaud]

the fuel run is no problem, but isn't the injector very sensitive for tiny bits of dirt?

[IgorVigor]

yes, but for a quick test, it might be worth just trying it...

I wouldn't recommend running without a filter all the time, but if you remove it from the equation, you can either eliminate it as the problem or find out that it is the problem...

besides its an easy test and easy fix...

a few of my friends do/did motocross racing and they all used to use the wire gauze type fuel filters rather than paper as they work just as well, but not as restrictive...

[arnaud]

Well the new filter lets the fuel through easily.
Waht about puring some ethylalcohol in the fuel line?
it is said to bind the water..

[Nanko]

Did you (re)check the valve clearence?
The white "smoke" can be unburnt fuel due to compression loss

[TimppaX]

Blocked air filter might also be the reason for this

[arnaud]

Valve clearance is double-checked,
The air filter element is new.
I tried loosening the fuel pipe nut at the injector side, it shut down right away.
Makes me think.. i re-tightened both ends again. i am afraid to use serious force here..

[arnaud]

i did not take apart the fuel pump, but did take apart the injector. i got it tested an an additional .25mm is added to the shims.
Can this problem be caused by a faulty injector?

[Nanko]

Can this problem be caused by a faulty injector?

Yes , when the needle is stuck in the open position fuel is not atomised
Drops are difficult to ignite and the fuel leaves the engine as white smoke.
A healthy injector makes a cracking sound when injection takes place.

[arnaud]

I cannot identify the sound in the midst of all the engine noise.
Butwhat could i have done wrong? it is tested and prayed okay..
Can half-a year old diesel be the cause?

[IgorVigor]

you should be able to hear the injection noise while the engine is decompressed...

I wouldnt have thought that old diesel would be a problem...
A stationary engine I have has got fuel thats around 2 years old, and it still runs nicely...

[TedV]

double check the injection timing? Verify compression is good? Do a leak down test? Just cause the engine has been overhauled doesn't mean all the internals are sealing like they should. rings might not have seated well.

old diesel fuel can cause running problems. Friend and I were talking the other day how we can smell the difference between new diesel and crap nasty fuel. A clean gallon jug, with a clean hose going to the pump will tell you if it's a chassis line/filter problem. might not be easy to ride it that way tho.

[IgorVigor]

as for checking the piston rings, a trick to try is dribble a bit on engine oil into the cylinder (either through the intake or the injector hole...

the oil will temporarily seal the bore better...if its a big improvement in compression, you need new rings...

[arnaud]

i did not alter anything about the timing whatsoever. the compression feels very well.
i can hear the clack of the deco lever coming back when starting, but after that..
it can run okay, and made 2 trips which were allright apart from the start. the engine responded like it should.
now it sticks in the first state, the power falls away, gets back again, and sometimes stays away.
Very annoying when youre not the only one on the road..

[Nanko]

I cannot identify the sound in the midst of all the engine noise.
Butwhat could i have done wrong? it is tested and prayed okay..
Can half-a year old diesel be the cause?

When turning over the engine while decompressor is used and throttle fully open
you should hear the sound.

About old dieselfuel , I just bought a car which was stored for 10 years , apart from
changing the timing belt I did nothing , it started on the old (but clean) very strange
smelling fuel.
This was the good old stuff , I bet the bio-dino mix is worse......

[IgorVigor]

I never thought of that nanko...

modern fuel is low sulphur isnt it :S

the engine outside has got a drop of red diesel (old style fuel, with lots of yummy sulphur )

[sbrumby]

I know you say you have not altered the timing, but white smoke usually means retarded and lower power.

[Crazymanneil]

Does the engine have glowplugs? Are they working?

As others have said, maybe unburned diesel, especially when cold.

Good luck.

Neil

[arnaud]

I know you say you have not altered the timing, but white smoke usually means retarded and lower power.

The sound is very knocky, it is hammering as it was new, despite of the extra shim in the injector.

[coachgeo]

sounds like an air leak to me. Is their a fuel pump at all or gravity fed? The IP may put some vacuum on the fuel lines. That could be enough for one of the fittings to be sucking air.

Try running the bike temporarily out of a small fuel can with a well submerged fuel line inside the can with no filters. In fact.... make it a can of Lubramolly Diesel Purge. Will clean your engine's fuel system at same time. If it runs good, attach can's line thru the fuel filter your using. Now If it runs good you've eliminated alot of things. If it runs the same.... well you've eliminated other things.

Also... could you have some junk intermittently blocking the fuel port out of the tank? does that fuel port have a screen? Sometimes they do.

[arnaud]

Hi, everyone thanks for the help. but i am really sure that
1 diesel fuel is running good from the tank, through the filter to the fuel pump of the engine.

2 no air leak; one time i had a small tear in the fuel line and diesel was quirting out(making the rear tyre slippery).
All rubber tubes are new and secured well and no bubbles in the fuel filter.

can it be a fuel pump problem? i did not take it apart, only removed it from teh engine in order to get the camshaft out safely.
i will take the metal fuel line from the pump to the injector off again, and look for dirt on the fittings..

[BoxerOtto]

after adding the shim to your injector, it was intended to increase injection pressure correct? so if the pump is not able to deliver past higher set pressure it may be causing you grief. it would alter your timing because it takes the pump longer to achieve firing pressure. also check fuel tank vent, i remember diesel dave having trouble with running slower and slower till it quit. Also not a very good idea to ever run without filtration.

[arnaud]

Hi, the engine is running fine again.. a i mentioed, no air leak..
i filled the fuel line with 2 caps of ethylaclohol and started a good trip.
No complaints since then..

[John]

Well the new filter lets the fuel through easily.
Waht about puring some ethylalcohol in the fuel line?
it is said to bind the water..

Hi Arnaud. Do not use a metal gauze for your diesel filter as another poster suggested. Diesel injection pumps are incredibly sensitive to grit or particles, & can be completely wrecked by particulate matter of only a few microns, due to the extremely finely machined surfaces & minute tolerances. They are designed for very fine paper filtration in the fuel line because they need it. Petrol engines, even ones with electronic injection, operate at a tiny fraction of the injection pressure of a diesel, which can be quite adequately supplied by an electric pump. They can get by with fairly modest filtration standards. Our little industrial singles may have the most basic simple mechanical injection technology compared to modern high tech car diesels, but if you want long life from the pump, give it a first class fuel filter.

[arnaud]

Seems like valuable info, thanks!