Generator fuel pump Bosch Mini

Good day All:

Has anyone had any luck rebuilding, then reinstalling the Bosch Mini fuel pump?

My Nextgen Generator has died. Tracked to a dribble out of the high pressure outlet of fuel pump. Found a new pump for 425. Then found a rebuild kit for 180.

Any comments or experience rebuild versus replace?

TIA.

Of course you have checked your fuel filter first?

MAKE SURE THERE IS FUEL TO PUMP. Fuel pumps are pretty reliable and easily rebuild-able.

I changed my pump out with a generic electric pump. easy.

This has both an electric lift pump and the high pressure injection pump. The electric pump is fine. But almost nothing (maybe a drip) comes out of the injector line after cranking for a while. Should be a squirt every rotation of the crank.

Generally speaking NO:

The injection pump is responsible for delivering squirts of fuel to each cylinder at precisely the right moment. The quantities involved are tiny – typically about a twentieth of a drop in each squirt – but they have to be accurately measured and at enormously high pressure. To do all that calls for very high precision machinery
Most if not all injection pumps require calibration/metering flow and pressure , this requires hooking up to very complicated and expensive equipment all done in hospital cleanliness or actually even cleaner!!,

Done at home normally ends in disaster if not sooner definitely later as incorrect settings lead to melted pistons in the worst case or just VERY poor running engines

Cheers Steve (NZ Chief Eng 1)

Make sure the plunger and rack are not stuck. Common for them to stick if sitting for a long time. If stuck sometimes a little finagling can free them, or take pump to a shop to get torn down and cleaned. Usually no damage from this, just needs a cleaning.

CaptSteve53 said:

To do all that calls for very high precision machinery

Most if not all injection pumps require calibration/metering flow and pressure , this requires hooking up to very complicated and expensive equipment all done in hospital cleanliness or actually even cleaner!!,



Done at home normally ends in disaster if not sooner definitely later as incorrect settings lead to melted pistons in the worst case or just VERY poor running engines



Cheers Steve (NZ Chief Eng 1)

Click to expand...

Just talked to my retired chief and he reiterated your comments. Thanks for the info/confirmation. Guess this is one I'll have to hire out.

Had the local yard mechanic check it out. Says 350 to remove/ rebuild, or 425 for new. With 30 day guarantee on rebuild. One year new. So new it is.

One more winter gone by.
To close this one out... The local yard (no names) had the boat for 5 weeks. Accomplished nothing. Sent me a bill for $675. Blamed.... bad fuel tank, bad injection pump, bad lift pump, bad fuel. bad bad bad.


Disgusted, I removed Generator this winter, took it to local Kubota dealer and they said it just needed cleaning. So, while it was on the bench they pop tested the injector, checked the glow plug, ran it for 3 hours. done. Total bill. $675 I Reinstalled and Done (I thought).


Ran for 1.5 hours and quit. Hooked up a gallon container of diesel. Bled it, ran like a champ.

Fuel. Took hose off pumped 2 gallons out with lift pump in a minute. Turned it off, then restarted, no fuel.

Removed fuel tank dip tube. suspected crack or other defect. None noted. Reinstalled dip tube and barb, hooked up lift pump. Repeated earlier results.
Why would it pump for 2 gallons, then nothing?

Took tank inspection port off. Used bore scope to look in back of tank. There was a piece of a fuel diaper wedged in the corner of the tank by dip-tube. Removed that. Then re removed the dip tube, this time I removed the dip tube from the aluminum threaded fitting. Packed inside was about 2 Qtip balls worth of oil absorbent diaper material! I've heard stories about people using diapers to wipe tanks when cleaning, it's a No No. I have proof!

Currently awaiting delivery of new dip tube and new hose. Figure while I have it apart, renew hose to secondary filter. Debating installing second large dip tube to run fuel polisher off of, separate from fuel fitting.