How to bleed an M25?

[Steve Treppa]

Help!I've replaced the fuel filter on my 1986 Cat 30 w/ Universal M25 and lo and behold - She won't start!I've bled the fuel filter by loosening the nut on the top and fuel ran out. And I've also loosened the "knurled knob" on the injector pump but no fuel flows out. I did notice that the ticking produced by the fuel pump increases when the knob is opened, however....Is there some other point in the system that I need to bleed? Do the injectors need to (or can they) be bled? The manual that came with my engine STINKS as far as this process is concerned.Any help from those who have done this before would be most appreciated!!!

 

[Dave Emery]

How to bleed a M25

I replaced the filters on my 1989 M25XP last week for the first time (for me). I too read the manual about the bolt at the top of the engine fuel filter and the knob at the injector pump. The bolt at the top of the engine filter looked like it had never had a wrench on it, so I moved on to the knob at the injector pump. When I opened the knob the electric pump ran faster and slowed down to its normal ticks when closed. You will not see fuel or hear air at this bleed point, it bypasses the injectors and returns to air and fuel to the fuel tank via the injector return hose. What I did was to prime (fill) the filters with clean fuel prior to installing them. I then opened the bleed knob for approx. 1 minute, closed the knob and started the engine. It worked great. If you did not fill the filters prior to installation it may take a while for the small electric fuel pump to bleed the entire system. Good Luck, Dave

 

[Steve Treppa]

I guess I should add....

The engine DID run for about 5 min. after the fuel filter change, then sputtered, a big cloud of white smoke belched out of the exhaust, and it died.....<weep!>

 

[Richard Gresham]

M-25 fuel bleed

Steve,I too have changed my filter for the first time this past weekend. But i didn't bother with the bolt on top of the fuel filter. I just spun the new one on and opened the knurled nut and let fuel pump run until it slowed down(1-3 mins). I thought it would have bleed fuel all over but it didn't. I closed the nut and cracked (gently) the injector nut all the way off and saw that there was fuel to the injector. I replaced the injector and re-tighten. Glow and go she fired right off. Its has run for about 30-45 mins since. Maybe beginners luck, but, the next place for you to check would be fuel at the injectors. Make sure your knurled nut is closed all the way...let us know how it works out.Richard

 

[dave bouquet]

Fuel Filter part numbers

This post has my thinking. I was planning on replacing my filters on the M-25XP as well, but I have questions about the rancor water/fuel separator. Did you replace the filter in that unit as well as the fuel filter or just the fuel filter? Steve, do you have the make and model number of the filter? That would be a help. What's the current status? are you up and running? (as you can tell i'm very interested!)