Regulator controls for small diesels

Getting the pumbing right for your Diesel fuel feed..

Moderators: Dan J, Stuart, Diesel Dave, Crazymanneil

Post Reply
User avatar
Diesel Dave
Site Admin
Posts: 924
Joined: Sat Dec 02, 2006 1:21 am
Location: Essex, UK
Contact:

Regulator controls for small diesels

Post by Diesel Dave » Thu Jun 11, 2015 2:21 pm

Just a small piece to help those scratching their heads when it comes to the regulator controls and functions for stationary type engines.

I'll try and keep things as simple as possible and no doubt the cognoscenti will pitch in if they spot any errors.

All stationary diesel regulators have 3 basic adjustments:

1) Idle speed
2) max free-load speed
3) Max fuel inject volume - sometimes referred to as 'rack' or 'rack max'

So firstly you need to realise that the cable control you connect to the twist grip is not a 'throttle', more like a ships telegraph whereby you request certain revolutions from the engine room. You can feel this when you ride as holding the twinstgrip in a fixed position over an undulating road will cause the motor to 'fuel up' on the inclines and shut off on the downhill bits - this can really catch you out when you use bigger engines especially on roundabouts.

So idle speed - seems pretty obvious although on some fittings they rely on the control cable tension to set this - not good on a motorcycle, hence the additional fittings on Henry Price's Yanma clone installations. A word of warning, do not set this too low, for a single they usually need 1200 rpm as a minimum. Whatever you do don't let the motor start 8 stroking with a heavy banging ignition as this can destroy a crank or balancer shaft in short order. Essentially what is happening is the governor senses the engine speed is too low and puts the injector to full so as to prevent a stall. This leads to huge accelerations of the flywheel and ancillaries such as balancer shafts and their drive gears - not good.

Max free load speed - pretty much as the name suggests and easy enough to set of you have a tacho. Be aware of 'regulator droop', this causes the max speed to slow as the motor gets hot so most workshop manuals suggest setting it 1500 rpm higher than the 3600 setting to allow for this phenomenon. Don't be silly at try and get your single to rev to 4000+ it will only destroy itself and possibly take your head/leg/arm off when it let's go.

Max Fuel Inject Volume - this is commonly the most misunderstood control as some think of it as a key to endless power. It will usually be wire locked if new and will have a spring loaded tip. This controls the maximum volume of fuel the injector can deliver; nothing else. Now for the controversial bit.....If you fit a small diesel to a motorcycle you should consider turning this DOWN; whoa! stop shouting and I'll explain why.

In the normal engines fitting be it a concrete mixer, pressure washer et all, firstly the requirement was for 7hp then they would fit a 10hp motor as suddenly chucking a few spadefulls of wet sand into the bucket will suddenly increase the load and the motor needs to cope. Under this circumstance the motor will OVERFUEL briefly to gain the absolute maximum immediate response (chucking in 50% extra fuel may gain you 10% over power but a lot of unburned black smoke).

When your charging down the motorway on your Yanclone/Hatz/Lombardini and pulling the wire hard against the stop you can get into the over- fuel condition for long periods of time. When this happens not only will your fuel consumption go through the roof but cylinder temperatures will rise to possibly damaging/seizure territory.

Here's my rendition of a typical Yanmar clone dual spring setup:

Image

So you have 2 rotating arms connected by 2 springs, inside the casings will be the governor speed control and the arm that connects to the injection pump.

As you can see the max inject control is set directly on the lower pivot whereas the max speed and idle speed are set on the upper, so no matter how hard you pull on the control you cannot bypass the max inject function, also the controls INFLUENCE the lower control but do not INSIST, as they are only connected by the spring tensions. If you experiment and bypass the upper control function and attach a cable directly to the lower pivot you will find out just how hard the governor will pull back against your wrist.

I hope this helps.

Feel free to pitch in.

User avatar
Tetronator
I luv the smell of Diesel...
Posts: 474
Joined: Mon Apr 07, 2014 11:50 am
Location: Amsterdam
Contact:

Re: Regulator controls for small diesels

Post by Tetronator » Thu Jun 11, 2015 5:17 pm

Very informative Dave. Good job!
"...the fearless Dutchman..." -Stuart
"...the mad Dutchman..." -Diesel Dave

Honda VT600 C Shadow
Image
H̶o̶n̶d̶a̶ ̶C̶B̶R̶6̶0̶0̶F̶2̶
Image
Mercedes-Benz W123 300D Sedan
Image

UAofE
I luv the smell of Diesel...
Posts: 225
Joined: Sat Sep 20, 2014 6:39 am
Location: Denver, CO USA

Re: Regulator controls for small diesels

Post by UAofE » Fri Jun 12, 2015 10:20 am

Diesel Dave wrote:Under this circumstance the motor will OVERFUEL briefly to gain the absolute maximum immediate response (chucking in 50% extra fuel may gain you 10% over power but a lot of unburned black smoke).

When your charging down the motorway on your Yanclone/Hatz/Lombardini and pulling the wire hard against the stop you can get into the over- fuel condition for long periods of time.
Turbo.
Last edited by UAofE on Wed Jun 17, 2015 12:21 pm, edited 2 times in total.
2006 Honda Rebel
Kubota OC95, Comet 44C/44D

User avatar
Diesel Dave
Site Admin
Posts: 924
Joined: Sat Dec 02, 2006 1:21 am
Location: Essex, UK
Contact:

Re: Regulator controls for small diesels

Post by Diesel Dave » Fri Jun 12, 2015 2:09 pm

Addendum.

As regards the Max Fuel adjuster.

Note that most of these will have a spring loaded tip, this is to allow for brief overfueling but as stated earlier not for more than a few seconds. In fact it's really not needed on a motorcycle fitting and can be removed (glue up the spring with JB Weld or replace the spring with a ball bearing or other bit of metal). It will save you the sudden jerk you get when rolling on the throttle after overrun and also save the driveline shock.

Another comfort addition.

If you install a spring in the throttle pull cable, it has to be stronger than the regulator control springs, but you will find it more comfortable to hold full throttle for long periods - useful for long motorway journeys on your 10hp bike.

skoleskibe
I luv the smell of Diesel...
Posts: 58
Joined: Fri Mar 18, 2011 9:45 am
Location: Denmark

Re: Regulator controls for small diesels

Post by skoleskibe » Wed Oct 14, 2015 1:05 am

I still dont get the second spring.
I've just replaced the max fuel with a 8mm bolt.

Can you explain the physics of the 4 times 3 different spring settings on the rack?
Regards Kim
( mz ts 250 with yanmar l100 comet 40)

User avatar
Diesel Dave
Site Admin
Posts: 924
Joined: Sat Dec 02, 2006 1:21 am
Location: Essex, UK
Contact:

Re: Regulator controls for small diesels

Post by Diesel Dave » Wed Oct 14, 2015 7:20 am

Having 2 springs allows the control spring to be a lot lighter = finer control.

You could do it with a single spring but to have the same effect it would need to be dual rate, if it was just a single spring the on/off control would be rather harsh.

The differing spring positions on the arms just allow for different control tensions to be set = stronger = higher revs.

bf109v7
I luv the smell of Diesel...
Posts: 103
Joined: Sun Feb 08, 2015 7:08 am
Location: Philippinen

Re: Regulator controls for small diesels

Post by bf109v7 » Wed Jan 27, 2016 7:40 am

In 3b my engine did only 2600, I put the sping in 2a and get 4000 now. I will use the 4000 only for overtaking, normal running is about 3000 with the Throttle little bit released.
Alex

klondikekid
I luv the smell of Diesel...
Posts: 87
Joined: Sat Dec 06, 2014 11:25 pm
Location: Canada

Re: Regulator controls for small diesels

Post by klondikekid » Sat Jan 30, 2016 5:56 pm

I know Yanmar and Kubota are similar in alot of ways, and was wanting to know if the spring settings for my d950 3 cyl kubota are similar? I guess could find a shop manual and find out, but like to hear first hand.

User avatar
coachgeo
I luv the smell of Diesel...
Posts: 1997
Joined: Sun Feb 22, 2009 6:00 am
Location: USA Ohio, Above Cincinnati, Close to Dayton

Re: Regulator controls for small diesels

Post by coachgeo » Sat Jan 30, 2016 6:09 pm

klondikekid wrote:I know Yanmar and Kubota are similar in alot of ways, and was wanting to know if the spring settings for my d950 3 cyl kubota are similar? I guess could find a shop manual and find out, but like to hear first hand.
Me thinks 3cyl injection pumps are completely different animals. While probably conceptually similar, actual set up is very different. Don't quote me on that though.

For example to get more RPM on the 3cyl Kubota's and others I do believe to get more RPM's you simply have one *screw to adjust. "Rack Screw"? "rack adjuster"? I believe it is termed

* often sealed, but unsealable

User avatar
Diesel Dave
Site Admin
Posts: 924
Joined: Sat Dec 02, 2006 1:21 am
Location: Essex, UK
Contact:

Re: Regulator controls for small diesels

Post by Diesel Dave » Sun Jan 31, 2016 1:30 am

Rack screw = max fuel adjuster.

bf109v7
I luv the smell of Diesel...
Posts: 103
Joined: Sun Feb 08, 2015 7:08 am
Location: Philippinen

Re: Regulator controls for small diesels

Post by bf109v7 » Sun Jan 31, 2016 10:20 am

This rack screw also limits the max power. When is hang the spring in 2a, I also opened the rack screw. And I reached more than 90 Km/h.
But, going uphill I left real bad black smoke behind me. So I turned it back in a few turns. No more black smoke, but top speed is only 80 Km/h. This scew is not easy to reach on my byke, and legal speed is 60 km/h, it will stay as is.
Alex

arnaud
I luv the smell of Diesel...
Posts: 330
Joined: Tue Apr 29, 2008 11:11 am

Re: Regulator controls for small diesels

Post by arnaud » Mon Mar 26, 2018 4:09 pm

Im sorry to kick this topic up but i'm a little insecure about what i thought to understand. I really feel my 13 HP yanclone misses some power at upper rpm's.
For the maximum output the big spring should be set - in the drawing above- in the outer holes, 1-a.. right??

Post Reply