Beta 20 (Kubota) will not idle (? Injectors)

[Bobcat]

Hi Folks - any ideas?

Beta 20hp only runs at high RPM and cuts out above the idle speed (at about 950rpm indicated but gauge may be faulty). This following a 6 month layup ashore installed in the boat and just after fitting a new fuel hose, cleaned fuel filter/water trap and bleeding the system. This happened even when the engine was hot.

It initially started at the first attempt but then cut out after about 30 secs. For the initial 30 secs it ran perfectly. Re bled the whole fuel system and checked for air locks and fuel flow up to and including the fuel pump and injectors. It is rough running but on all 3 cylinders. After the engine warmed up it was possible to reduce from the very high rpm gradually but not to the idling rpm or smooth running.

I should also mention that when it was test run last season in the boat laid up ashore, it was without a fuel filter but with a new (clean) fuel tank and marine diesel.

RPM gauge is only reading up to 1000rpm even when revved up well beyond and it doesn't always return to zero (but this maybe a separate issue). Before removing the injectors for testing and/or the fuel pump any ideas or advice would be much appreciated. Could this be caused by blocked injector/s from sediment in the fuel pump or elsewhere? Many thanks for any help.

[Stu Jackson]

Do you have a separate electric fuel pump? If so, is it working? Is you fuel tank above or below the engine?

[leftbrainstuff]

You might want to check injector pump travel and the throttle travel. Someone may have fiddled with adjustments they shouldn't have.

You mentioned there was no fuel pump initially. A definite no non on a diesel. That alone would tempt me to have the injection pump and injectors refurbished. Costly though.

Is the engine discharging smoke when running? If so what color and at what rpm range?

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Bobcat]

Originally Posted by Stu Jackson

Do you have a separate electric fuel pump? If so, is it working? Is you fuel tank above or below the engine?

Thanks. No electric fuel pump as far as I know. Fuel tank above engine>

[a64pilot]

No chance a mouse built a nice little nest in the airfilter is there?

[Bobcat]

Thanks for input. No mouse but will re check the air filter just in case it is blocked since that is one thing I haven't rechecked recently!

[Bobcat]

Originally Posted by leftbrainstuff

You might want to check injector pump travel and the throttle travel. Someone may have fiddled with adjustments they shouldn't have.

You mentioned there was no fuel pump initially. A definite no non on a diesel. That alone would tempt me to have the injection pump and injectors refurbished. Costly though.

Is the engine discharging smoke when running? If so what color and at what rpm range?

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

Thanks for that. There is a Fuel Lift Pump and a Fuel Injector Pump and engine starts and goes well at high RPM seems OK - fuel squirts out of injectors. No Smoke. The Fuel Tank is well above the engine.

[Charlie]

It sounds like an air problem to me. Can you install a short piece of clear hose somewhere in the system to see if there are any bubbles coming thru the fuel system.

Another thought would be to check the throttle adjustment.

[Wotname]

Originally Posted by Bobcat

Thanks for that. There is a Fuel Lift Pump and a Fuel Injector Pump and engine starts and goes well at high RPM seems OK - fuel squirts out of injectors. No Smoke. The Fuel Tank is well above the engine.

Reading between the lines I think Leftbrainstuff had a typo in his post you referenced. I'm assuming he really meant to say that initially you had no fuel FILTER rather than fuel pump. Having run the engine without any fuel filter MIGHT have caused some injector pump problems but IMO, this would be very dependant on how long it was run and just how clean the fuel was initially.

Just to be clear, did you actually have no fuel filter at all or only no external filter. I would have expected there would be a Beta fuel filter as part of the engine fuel piping and it would be unusual to have bypassed this.

[Wotname]

With a gravity feed fuel system, it is unlikely to be air problem unless the leak was massive and therefore very noticeable.

[DeepFrz]

Check the fuel return line to make sure it isn't blocked.

[Wotname]

Given your history of the problem, it does sound like some tiny piece of crud was dislodged during the recent maintenance and found it's way to the injector pump/governor.

However sometimes coincidence does occur and the issue may be unrelated. Have you checked the mixing elbow for blockage?

[Bobcat]

Originally Posted by Wotname

Reading between the lines I think Leftbrainstuff had a typo in his post you referenced. I'm assuming he really meant to say that initially you had no fuel FILTER rather than fuel pump. Having run the engine without any fuel filter MIGHT have caused some injector pump problems but IMO, this would be very dependant on how long it was run and just how clean the fuel was initially.

Just to be clear, did you actually have no fuel filter at all or only no external filter. I would have expected there would be a Beta fuel filter as part of the engine fuel piping and it would be unusual to have bypassed this.

Last season I removed the external fuel filter to clean whilst installing a new fuel tank and hose. I just wanted to see if the engine would run after an extended layup which it did. However, when I tried again after refitting the fuel filter this year the problem started.

[Ziggy]

Originally Posted by Bobcat

RPM gauge is only reading up to 1000rpm even when revved up well beyond and it doesn't always return to zero (but this maybe a separate issue).

It seems like your tach is not giving you a reliable measurement. It might be worthwhile to measure the engine RPM with a strobe light, on the off chance that your idle is set too low.

[Bobcat]

Originally Posted by Bobcat

Hi Folks - any ideas?

Beta 20hp only runs at high RPM and cuts out above the idle speed (at about 950rpm indicated but gauge may be faulty). This following a 6 month layup ashore installed in the boat and just after fitting a new fuel hose, cleaned fuel filter/water trap and bleeding the system. This happened even when the engine was hot.

It initially started at the first attempt but then cut out after about 30 secs. For the initial 30 secs it ran perfectly. Re bled the whole fuel system and checked for air locks and fuel flow up to and including the fuel pump and injectors. It is rough running but on all 3 cylinders. After the engine warmed up it was possible to reduce from the very high rpm gradually but not to the idling rpm or smooth running.

I should also mention that when it was test run last season in the boat laid up ashore, it was without a fuel filter but with a new (clean) fuel tank and marine diesel.

RPM gauge is only reading up to 1000rpm even when revved up well beyond and it doesn't always return to zero (but this maybe a separate issue). Before removing the injectors for testing and/or the fuel pump any ideas or advice would be much appreciated. Could this be caused by blocked injector/s from sediment in the fuel pump or elsewhere? Many thanks for any help.

Below are some checks suggested by Tech Support which might be of interest to others or worthy of further discussion.

1. Check Stop Solenoid is OK ie lever free and button/key working (no need to start engine).

2. Check Loop in the hose up to the fuel lift pump which prevents 'drain down'.

(Drain Down necessitates bleeding fuel each time if engine left unused for long time)

3. If Fuel Contamination suspected take supply direct from a clean container to lift pump.

4. Re Bleed from fuel tank to injector pump and injectors if necessary and try again.

5. Check if Injector Pump Spring has broken possibly due to corrosion eg water in system.