The Classic Machinery Network

Hi
My dumper has developed a popping noise through the exhaust when revved at full throttle
It starts easily but when under load it has no power eventually slowing down with a cloud of black smoke
Ive changed fuel filter and bled the pumps
Any advice very welcomed
Thanks in advance

My initial guess would be that you have a valve that is not seating correctly or burn't out, do you have decent compression on the engine? If the answer is yes then I wonder if you have a weak exhaust valve spring?
Just a couple of leads for you.

Jeremy

Hi,
As Jeremy says it sounds like a valve problem but it's not unknown for these engines to build up carbon in the exhaust ports, give the same symptoms and struggle under load.
Particularly if subject to long periods of idling or over fuelling, ( Running with the cold start excess fuel setting engaged), or simply after long service.

If you remove the manifolds you will be able to see if this is the case. If so, and you don't want to remove the heads, as a quick fix you could run the engine without the manifolds and dislodge the carbon from the port with a long screwdriver. The exhaust will blow out the carbon as you go.

Wear a glove and watch your eyes if you try this, but don't be afraid of it. I have done this successfully on several occasions where the engines have been on pumps which could not be stopped long enough to do the job properly.

Fred

Hi and many thanks for your response however today i removed the air filter and drove the dumper with a full skip it went well and never black smoked only problem was whever i touched the stop control on the engine the same issue came back
Yes the engine has good compression and starts on the key easy

Just a thought i set valve clearances at 0.06 is this correct

joefen wrote:Just a thought i set valve clearances at 0.06 is this correct

Hi,
6 thou. is the correct clearance.
Fred

joefen wrote:Hi and many thanks for your response however today i removed the air filter and drove the dumper with a full skip it went well and never black smoked only problem was whever i touched the stop control on the engine the same issue came back
Yes the engine has good compression and starts on the key easy

Okay so first and easy cheap step replace the air filter element, next step look at the stop control, I have no knowledge of how the stop control works on this engine I would assume it goes to the fuel injection pump?

Jeremy

Hi,
The stop control not only moves the rack to cut off the fuel and stop the engine but also sets the maximum fuel delivery.
When turned anti clock.it allows the rack to move to the excess fuel position for cold starting.
The page below from the manual for setting this up shows setting G which will be about 0045 in.
Possibly the control plate has become loose and needs re setting or the spindle is not holding against the control plate stop There should be a spring inside at the back of the spindle to keep it tight against the control plate, may be there's something adrift there
Fred

FOWLER MAN wrote:

joefen wrote:Just a thought i set valve clearances at 0.06 is this correct

Hi,
6 thou. is the correct clearance.
Fred

but 0.06 is 60 thou

tfox wrote:

FOWLER MAN wrote:

joefen wrote:Just a thought i set valve clearances at 0.06 is this correct

Hi,
6 thou. is the correct clearance.
Fred

but 0.06 is 60 thou

Yes tfox.
Six thou. (0.006), is the correct clearance as I said.

0.06, (60 thou), would be over a sixteenth of an inch.
Well spotted.

Fred