[1999 41.5]

Good cranking voltage, full fuel tank, new filters (changed after problem started) It tries to start and in fact actually ran a few times but lost rpm after a few seconds and stopped. I think it's a fuel problem but not sure on how to trouble shoot it. It's a 1999 coach with a Kohler 20K unit.

[encantotom]

only two things....fuel or air

check the electric fuel pump mounted on the engine.

tom

[HoosierDaddy]

It is easy to check the fuel shut-off solenoid. It is on the right side of the engine (Yanmar) There will be a rod that runs from the solenoid to the fuel pump. Make sure it fully opens and stays open as it cranks and runs.

[encantotom]

That is an easy one to check.

I had the fuel pump go bad on mine

Tom

[folivier]

Also make sure the wire connections on the fuel pump are tight. Happened to mine one day and generator kept shutting off while driving. Just a thought.

[Richard]

To take Forest's suggestion, one step further, you can reach in and hold the fuel shutoff solenoid open while starting the engine. It will force it to run.

If it runs with it held open, but closes as soon as you turn it loose, then you may have other issues. The control system may think you have high temp or low oil pressure, and it automatically shutting it down.

[bikestuff]

On some coaches there is also a cutoff if the the fire extinguisher thingy is not full. (Most have been bypassed by now, I suppose)

[bestgenman]

You are not getting fuel to the delivery valves of the high pressure injection pump. The high pressure injection pump has the steel lines going to the nozzles. The most common problem is plugged fuel filters but in your case, you have new filters so not likely unless bacteria has your fuel contaminated. Several units have a momentary switch to operate the lift pump (an electric pump to bring fuel to the high pressure injection pump), most Kohler sets used a Carter pump but any 5 psi ~ output pump will work.

Get power to the lift pump either by the switch or temporary jumper. Remove the inlet line to the high pressure injection pump from the secondary filter and see if there is fuel flow. If no flow, try the hose on the outlet of the lift pump. If no flow there your lift pump is not working, if there is flow your filters are plugged.

Hope this helps
Gordon

[ccjohnson]

I had a diode in fuel pump wire go bad. I always thought it was just a connector. After a 5 hr drive to PHX & a 1hr min shop time bill I was ecstatic that myn parts bill was less than $10.

[bestgenman]

missed something!!

This is assuming your rack solenoid is pulling in. Use caution cranking too long as damage to the pull in coil will occur if operated (cranked) too long.

The statement about holding the solenoid in to see if the engine will run is good advice. This determines if the problem is fuel related or electrical.