Tune up, performance areas for B7100?

grossgary · Jun 19, 2011

Mows and drives fine but seems a bit lower on power than when we got it a few years ago. Seems to bog down going up steep grades more than I remember.

Changed all fluids - oils, trans oil, diff oils, axle oils, etc.
New air filter, fuel filter.

Any other tune up items I'm missing, I went through the owners manual and seems I have everything covered.

I'm about to adjust the valves when I figure out what the clearances are supposed to be. Doubt that will help though.

Sea Foam or cleaner in the fuel - is that worth any effort?

Maybe it's something else, wet or high grass or dull blades :laughing:

leonz · Jun 19, 2011

grossgary said:
Mows and drives fine but seems a bit lower on power than when we got it a few years ago. Seems to bog down going up steep grades more than I remember.

Changed all fluids - oils, trans oil, diff oils, axle oils, etc.
New air filter, fuel filter.

Any other tune up items I'm missing, I went through the owners manual and seems I have everything covered.

I'm about to adjust the valves when I figure out what the clearances are supposed to be. Doubt that will help though.

Sea Foam or cleaner in the fuel - is that worth any effort?

Maybe it's something else, wet or high grass or dull blades :laughing:

A MMM will tend to bog down in heavy wet grass.

Your muffler could be plugged with carbon affecting the performance of the engine.

You may have 1. water in your diesel fuel, 2.a herd of bacteria growing into a fungi farm in the fuel tank, 3. a plugged fuel tank strainer. Please check to see if you have a second filter as I am not familiar with this model.

I would also check to be sure the fuel tank cap vent is open as this sounds more like a venting problem.

You also may have fuel lines that are collapsing from the pressure gradient created by the injection pumps actual vacuum/Hg.If your fuel lines are original equipment I would think about replacing them with some Racor reinforced fuel tubing which has a wovemn fabric reinforecement within the rubber layes to prevent collapse of the fuel line during operation.

Before you even think about messing with the valve train run a can of Sea Foam through the fuel tank over several tanks of fuel and add some sea foam to the crank case running it a few minutes before you change the oil to break up the carbon on the exhaust side.

If you still feel you need to mess with the valve train (groan) The engine MUST I REPEAT MUST be cold for 24-48 hours before you even begin to do this
WITH THE SHOP MANUAL FOR THIS ENGINE.

grossgary · Jun 19, 2011

i have the largest 60" MMM out of 48" and 54" options as well. maybe it's normal, it's not a big difference, only really noticeable when going uphill.

not sure what the fuel tank vent cap is?

i'll check a few things, like the fuel lines and seafoam, like you mentioned but it might be a matter of just making sure i'm mowing often enough and not when wet.

Egon · Jun 19, 2011

The Fuel Vent Cap is the same as the diesel tank fill cap. You'll probably notice a membrane inside the cap and a little hole on the cap. That's the vent.

My Kubota did the same at one point about four years ago when I still had it. I assumed it had something to do with fuel composition.

dennis52 · Jun 19, 2011

Good advice from previous posts.

The valve clearances on my B7100 were way out and adjustment made a difference to performance. Check them with a feeler gauge.

Not complicated to adjust them ; there are plenty of posts on this and other forums to assist. Make sure you have the right tools.

Not a performance issue but did you clean your gauze transmission filter ?

grossgary · Jun 24, 2011

dennis52 said:
The valve clearances on my B7100 were way out and adjustment made a difference to performance. Check them with a feeler gauge.

awesome, thanks for letting me know, sounds promising and may convince me to tackle it tomorrow.

dennis52 said:
Not complicated to adjust them ; there are plenty of posts on this and other forums to assist. Make sure you have the right tools.

i've done most things automotive, torn down motors/trans, etc, this sounds like basic valve stuff now that folks have pointed out the important points. like make sure it's absolutely cold - it's mentioned so often i was thinking about waiting until winter:laughing: