B7100 - white smoke from exhaust at high RPM with occasional puffs

[RCW]

This one appears to me more like a combustion issue than making steam! The first thing I would do would be a compression test.. The injection shop meant fuel dilution, the most common fuel dilution is gasoline in the fuel. Maybe a complete draining of the fuel and replace it with known good diesel fuel is in order?

John - - if eserv says do a compression check next....that's exactly what I would be doing!

 

[JohnJohnson]

When I googled fuel dilution I got results referring to fuel diluting the oil, but the diesel shop told me to replace the fuel and clean out the lines so I suppose they were referring to something like gasoline in the diesel. I cleaned out the lines and tank as best I could, not sure if there is some residual gasoline. I swear the fuel filter cup smelled like gasoline, but I think that could be the fumes just getting to my head.

10-4 on that compression test, waiting on a glowplug adapter from ebay, Harbor Freight stopped selling their cheap diesel compression test kits and I have a diesel compression gauge already.

The exhaust is quite noxious, I would be surprised if someone would find it sweet smelling. The reason I haven't used the tractor at all is because it's impossible to stand next to without getting a splitting headache and feeling like your lungs and throat are on fire.

 

[Russell King]

Can you remove the exhaust manifold and see which cylinder is creating the white smoke. If that has the aftermarket injector (which anecdotal evidence says are all poor quality) then I would replace that injector (or move injector from cylinder to cylinder to see if problem follows injector?).

 

[twomany]

A good diagnostics is to just remove the exhaust manifold and see if all the white smoke is coming from one cylinder. (Is it the cylinder with the aftermarket injector?)

TThen swap injectors between cylinders and see if the smoke moves.


Takes an afternoon, and costs nothing.

edit

Russ just wrote the same thing.... oh well....what I get for not reading to the end ;-)

2nd edit

compression tests on these small engines is one royal PIA, Unless the set up has just the right adapter to get around the manifold. I can tell you, that adapter is not in the Snap-On kit.

 

[JohnJohnson]

I did a compression check and all three cylinders were at 350-375 psi. So it doesn't seem to be a compression problem.

I thought I knew how to check injector pump timing, but I guess I don't quite understand it. The 70mm stroke WSM says to look for the "FI" mark on the flywheel when the fuel reaches the top of the delivery valve, but I don't see any F1 marks through the inspection port, only markings that say, 20, 10, and 1TC, but I'm having a hard time being sure of when the fuel is being delivered to check it against the mark (I'm assuming the 20 mark since the fuel should be delivered before TDC). Does anyone have any tips on doing an injection pump timing check on the B7100?

Since I had to remove the glow plugs, fuel lines, and intake manifold to do the compression test I went ahead and tested the glow plugs. Two of them turn cherry red on the tip, the third heats up around the base, but not the tip. Still gets hot, I will replace that tomorrow. Not sure if that completely explains everything, but it's something.

 

[JohnJohnson]

Just a (hopefully final) update: So the B7100 has timing marks on the flywheel that marks every 5 degrees from TDC starting at 25 degrees and according to the WSM injection should start somewhere between 25 and 20 degrees before TDC. These marks only correspond to the most forward injector. The other two injectors do not have a direct way to test timing since timing is only adjusted by the use of a shim for the injector pump and not the injectors individually. I turned the fly wheel and found that fuel was coming up at 17 degrees before TDC meaning injection completed just after TDC (not good). I removed the shim that was there and replaced it with a much thinner shim and was able to move the start of injection to 22 degrees.

Now that the timing is within spec the smoking and coughing problem appears to be resolved. Thanks everyone for the help.

 

[Lil Foot]

Thanks for the update, learned something new today.