D750 / B7100 fuel adjustment.

[Mogs84]

Hi Folks,

My tractor seems pretty underpowered compared to some stories that I've read on here.

I've read about the capped fuel adjustment screw to increase fuel pressure, I suspect my tractor may have been 'turned down' at time of original sale at the dealer as it was only ever intended to be used for mowing a golf course.

Even under heavy loads and at the point where it's just about to stall I don't get ANY black smoke at all from the exhaust.

I want to be able to adjust it so that I am to gain a hp or two or at least bring it back to what it should be standard.

My problem, is that I have no idea where to find this screw.

Anybody able to take a picture of it circled for me?

Thanks guys.

 

[Dave_eng]

I do not think any knowledgeable forum members would advise just turning injection pump settings in the way you want to.

Suggest you download and study the free WSM.

http://kubotabooks.com/AutoIndex/in...s/&AutoIndex=30e261e116688b9bf31bf005f32b7413

Dave

 

[flashover1969]

Before doing this, change your fuel filter. Semi plugged up fuel filter can cut your power.

 

[North Idaho Wolfman]

Hi Folks,

My tractor seems pretty underpowered compared to some stories that I've read on here.

I've read about the capped fuel adjustment screw to increase fuel pressure, I suspect my tractor may have been 'turned down' at time of original sale at the dealer as it was only ever intended to be used for mowing a golf course.

Even under heavy loads and at the point where it's just about to stall I don't get ANY black smoke at all from the exhaust.

I want to be able to adjust it so that I am to gain a hp or two or at least bring it back to what it should be standard.

My problem, is that I have no idea where to find this screw.

Anybody able to take a picture of it circled for me?

Thanks guys.

The Adjustment for the fuel rack does NOT turn up the fuel pressure, it only adjusts the timing on the governor.
Adjusting it does not increase fuel or make more HP.
DO NOT mess with the adjustment!

You need to do some simple tests and adjustments to see if you can get it to run better.

One pull the valve cover and set the valves, loose valve adjustment will make it run bad.

Check, clean or replace the air cleaner as restricted air flow will directly reduce power.

Check/ clean / replace fuel filter.

Remove the fuel line to the injection pump and check for proper fuel flow to the injection pump.
To do this, Feed the injection pump via a bottle gravity feed from above, run the engine and check flow out of fuel line, it should put out a good pulsed flow.

If that doesn't improve operation, do a compression test, wouldn't be too surprised that you just have low compression, if that is the case nothing else will improve its operation, you will need to do a rebuild.

If compression is good then you need to have the injectors tested, worn or soft pop injectors will greatly reduce power.

Last would be to pull the injection pump and have it tested.

 

[Mogs84]

I do not think any knowledgeable forum members would advise just turning injection pump settings in the way you want to.

Suggest you download and study the free WSM.

http://kubotabooks.com/AutoIndex/in...s/&AutoIndex=30e261e116688b9bf31bf005f32b7413

Dave

I'm an engineer by trade with lots of experience in motorsport application, so I'm not going to just be 'turning injection pump settings' for the fun of it.

I'm just not entirely familiar with compact tractors, my issue being mainly the talk of it being 'capped' and due to where my tractor has lived most of its life before me most of what looks like a 'cap' is badly corroded, so I don't want to just try and remove them in case any damage is caused.

 

[Mogs84]

Before doing this, change your fuel filter. Semi plugged up fuel filter can cut your power.

I've already changed all filters soon after I bought it, namely because it has a HST issue that was caused by a previous owner fitting the wrong filters and fluid, so all filters have been changed, hence why I'm now looking at fuel pressure.

 

[Mogs84]

The Adjustment for the fuel rack does NOT turn up the fuel pressure, it only adjusts the timing on the governor.
Adjusting it does not increase fuel or make more HP.
DO NOT mess with the adjustment!

You need to do some simple tests and adjustments to see if you can get it to run better.

One pull the valve cover and set the valves, loose valve adjustment will make it run bad.

Check, clean or replace the air cleaner as restricted air flow will directly reduce power.

Check/ clean / replace fuel filter.

Remove the fuel line to the injection pump and check for proper fuel flow to the injection pump.
To do this, Feed the injection pump via a bottle gravity feed from above, run the engine and check flow out of fuel line, it should put out a good pulsed flow.

If that doesn't improve operation, do a compression test, wouldn't be too surprised that you just have low compression, if that is the case nothing else will improve its operation, you will need to do a rebuild.

If compression is good then you need to have the injectors tested, worn or soft pop injectors will greatly reduce power.

Last would be to pull the injection pump and have it tested.

Thanks for the response, I knew you'd be on top of this!

The first part of your response is slightly contradictory to some topics I've seen you reply to previously?
I've very definitely read responses on past topics that indicate increases in fuel pressure.

I'll definitely take your advise on the rest of it though, I've not yet done a compression test but am getting very little blow-by even while under load, so suspect compression could be good.

I'll look into valve adjustment as it's entirely possible it's never been looked at.

Thanks.