Diesel Fuel System question?

ns_in_tex · Sep 26, 2020

Hesston 1180, Fiat 865 engine.
Bogged down while mowing and died.
Changed the 2 fuel filters.
While trying to bleed as per manual, could not get any fuel with the hand pump.
We only had fuel in lower tank (below filter level) so figured we would pressurize the tanks at the filler neck and force it through.
Was able to get good pressure on tanks, but no fuel flow at filters.

My question is, does the pump block the flow, maybe unless the handle is in a certain position?
Or maybe my tank outlet is blocked.
What we might be overlooking?

Thank you for any suggestions.

TractorGuy · Sep 26, 2020

Don't know about your specific model but it sounds like the line is restricted. I would pull the line loose where ever it first gets to the engine compartment and blow back to see if it is free to the tank. Then I would look forward for debris that may be restricting the flow.

I fought a restriction on my backhoe when I first got it and finally found a little chunk of rust in the banjo fitting at the water separator.

ptsg · Sep 27, 2020

Being the Hesston a rebadged Fiat, I would check the fuel tank screen. The Italian liked to use a screen on the fuel tank, often with a shutoff ball attached to it.

I have had the same problem on another Italian crawler tractor, a 1960-ish gem, after checking all filters and lines, finally took the shut off valve and screen off the tank and it was full of crap and rust.

ns_in_tex · Oct 1, 2020

Well it was all my fault. My filters came with 3 rubber gaskets and 2 o-rings. Only 2 rubber gaskets were needed. I thought they were all the same, but were not. We installed the smaller gasket on the top of the filter (it should have been thrown away). It was blocking fuel flow. The larger gasket sealed the filter to mounting correctly and let the fuel in. All is well now.

ptsg · Oct 2, 2020

Easy fix! We always like easy fixes.

Thanks for letting us know the outcome. :thumbsup:

Tinhack · Oct 2, 2020

Yep, the CAV-style filters are made to fit many different machines and arrangements. The small O-rings are often used under the head of the filter mounting through-bolt. (Between the filter head and bolt/washer.)

I just installed a new 2-filter head on my "on-going" Ford project. A new fabricated bracket and one supply line mod is all it took. The new filter setup has a glass bowl and drain for water inspection/removal.