Lubrication for injection fuel pump

[Goker]

What lubricate do you recommend for my injector fuel pump? The label on the side says Diesel Kiki, use pure engine oil. The rest is Japanese.
More information: The unit's lubrication is self-contained. Unknowingly, the diaphragm pump on the side had been leaking diesel fuel into the cam compartment since I bought the tractor 3 years ago. It ran very quietly all this time. When the leak gave way, I discovered the problem and changed the diaphragm, thus eliminating the diesel fuel in the cam compartment. After consulting one source I decided to put in 30wt Royal Purple synthetic oil thinking it would be better then just regular 30wt, and the fuel injector pump became very noisy and knocking. This is an Iseki TL2301D (gray market, 1985) tractor. Thank you for your responses.

 

[DennisArrow]

For me, in my TL2300 I use just straight 30wt el cheapo whatever I have.........It makes a what could be called knocking noise, so dont know if that is common to the beast. If it was me, I would think that when you had diesel getting by the diaphram, that the diesel was lubricating and deadening the sound??????.........Perhaps now, I would go to straight just plain ol 30 weight or even higher to see if the knock persisted. If it does......start looking for a replacement or rebuild parts and wait for it to fail.........God bless.....Dennis