Injection pump interchangeability and hunting issue

[Aussie590e]

Hello,

I have a 4 cylinder 592e in my boat. The engine has been recently rebuilt but I'm having hunting issues. Firstly, it's fitted with a simms pneumatically governed injection pump. Is this pump specific to my motor or am I able to fit a p4596 or p4685 mechanically governed pump?

Do all the different incarnations (mk 1,2,3?) of the 592e have provision for a engine block mounted diesel lift pump?

My pneumatically governed pump looks to be in great condition, rack moves freely, has a new diaphragm, no leaks on the capillary tubes from intake to governor etc, but I have intermittent hunting below 1300rpm. Runs fine when cold, once warm starts to hunt hunt. Will run consistent from 1300-1500rpm. The governor adjustment screw makes no difference. Does the bypass valve (attached to diaphragm) have to be a neat telescopic fit inside the adjustment screw bush? Mine is in good shape but is not an airtight fit.

I'm looking a solution to fix my current injection pump, or alternatively choose the best pump to replace it with.

Thanks

[Brian]

The Minimec pump will possibly not fit on your engine block, the mounting holes were different and the mounting pads the wtrong shape.

Two things to check on your existing pump;

1. Is the breather clean? It is the gauze under the cap near the governor housing.
2. Have you tried adjusting the damper? Its the square headed stud with a lock nut on the front of the governor housing.

Another thing that was tried on tractors back in the day was to fit governor pipes of the same size. Originally they had one small and one large.

[Aussie590e]

Thanks for the reply Brian,

From my research there is a small concave adapter piece which bolts onto the block nearest the drive coupling which allows the minimec front bolt holes to line up, and then the minimec pump has a rear mount which attaches to the rear of the pump and then to the block.

Yes I have a clean gauze on the governor housing and i have 2 small steel capillary pipes, both same size. I have also adjusted the "damper" but no improvement.

Another Avenue I am going to look into is I had a build-up of carbon in the intake manifold. If the inlet valve clearance is too small and I'm getting a slight amount of combustion gas blowing back into the intake manifold, would this be enough to cause a hunt with the pneumatic governor?

[Emiel]

Hi,

What type of air washer have you fitted? I can imagine this influences the working of the governor.

Rgds Emiel

[Aussie590e]

Hi Emiel ,

Thanks for your reply. The engine has a marine spark arrestor, basically just some wire mesh. Do you think it's worth trying a paper element or something that will restrict flow a bit more?

Thanks

[Emiel]

Hi,

I'm not sure what you mean with a marine type spark arrestor.

On a vacuum governed Fordson tractor removing the air intake precleaner gives more engine rpm and other control behaviour.

Having another filter system with more or less underpressure certainly gives other control behaviour of your governor.

Try to block the air intake a little with duck tape ore something like that and see how the engine behaves.

Rgds
ET

[Aussie590e]

Hi Emiel, a marine spark arrestor is usually just a wire mesh filter for the intake, it stops any flame (due to backfire) out of the inlet manifold that could perhaps cause an explosion in a boat's engine room. In the next week i'll get out to the boat and i will try another air filter with more restriction, as well as check the valve clearances (inlet valve clearance is my concern) and report back to the forum.

Thanks