Universal M3-20B wont start after changing fuel filter

[mtcaddis]

I recently went on a three day trip. On the way back my engine would die when I brought the throttle down to idle and it requires the throttle be opened up partially to start it. Also when first starting it cold, the engine revs back and forth varying about 1000 rpm and does this for a few minutes until it warms up and finds a consistent rpm. I have not changed the fuel filters this year so I thought that may be the issue. There was no water in my racor primary filter/water separator. I changed the primary and secondary filters. The primary had some gunk in it and I couldn't see inside the secondary. I filled the filters up with fresh diesel before I screwed them back on. I have bled both bleed screws on the filter and on the injector pump. Fuels flows freely. I loosened up the fuel fittings on the top of the injector and no fuel flows out of the tube when cranking the motor or operating the fuel pump. Not even a dribble. My motor is supposed to be self bleeding but I have tried bleeding anyway and can't get fuel to come out of the injector inlets. I opened the air cleaner and found it was saturated in black oil. I cranked the motor with the air cleaner off to allow plenty of air and still no luck. My glow plug switch has always acted weirdly. Sometimes when I depress it, my oil pressure/water temp alarm will turn off as I am heating the glow plugs and sometimes that alarm does not turn off. I noticed it always starts easier when the alarm goes off while holding the glow plug button but it will still start even if the alarm kept beeping during glow plug warm up. I checked the wires on the back of the glow plug button to make sure that it is functioning when depressed. I don't know how to check glow plugs. And yes I have turned off my seawater seacock to prevent flooding of the engine.

I don't know what else to do. Tomorrow I will try to use some WD-40 as starting fluid to see if it will at least start with that. Any ideas would be appreciated.

[Lepke]

I have no experience with your motor but know diesels.

A diesel needs 3 things to start. Fuel, compression, and enough heat from compression to make ignition temperature. Glow plugs, block heaters, etc. help make temp in a cold engine. Your engine ran before the filter changes, so compression should be ok. Since you opened the fuel system I would start there. If your injector pump has a stop solenoid that is failing, it could explain the problems before the filter change. If the injector pump has a stop lever, make sure the lever is all the way on and any cable or linkage is tight. No fuel coming up the injector lines indicates a stop condition at the pump.
Make sure filters are tight. It's easier to suck air than liquid.
If you use ether, do it lightly. I have heard brake cleaner works with less risk if you don't know the safe amount of ether for your engine.

[HappyMdRSailor]

Welcome to CF mtcaddis!

Lepke is spot on... Do make sure your stop lever is "fully off" (or solenoid), and then try cracking an injector line at the pump while cranking or using the WD-40... If you do this and you can't get fuel there, there's a leak or restriction in the feed... or restriction in the return... Highly suspect a dirty tank...

[captjcook]

I believe it possible that your ignition switch contacts could be dirty/worn not making a good power connection to glow plug button, causing the easy/hard start related to glow plugs and warning buzzer. This is not the reason for not starting...Lepke and Happy have that covered.


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[grae]

I had this happen to me on my Vetus M2.05, new filter and no fuel flow, put the old filter back on and voila....

The 'new' filter I put on had been onboard for a while, the wrapping was a little loose and I can only guess but I suspect the filter had absorbed a lot of moisture over time (no basis for this conjecture so flame away!) which wasn't allowing the fuel to flow, I replaced the 'old' filter with a new new one when I got back to home port and no problems....

Since then I've been very careful about storing the backup filters in ziplog bags just in case and never had the issue again.

Grae Morrison

[DocRox]

Possible combination of issues, glow plugs not working and fuel blockage, remove and clean all electrical terminals from the battery, switch and glow plug relays.
Check fuel pressure, treat fuel with an Algeacide, backflush if possible then polish fuel recheck fuel pressure.
Good Luck

[cal20dennis]

Always start looking for problems where YOU last touched! (Make certain all filter gaskets are properly seated, also check all plugs/ fittings/ be sure both fuel filters are FULL...make certain you have no air leaks!) Since it sounds likely your diesel WAS starving for fuel before you changed the filters, disconnect the fuel line and BLOW air back into the fuel tank. Your engine is not going to start until you get fuel out of the loosened injector tube nuts while cranking. NO fuel=NO START! Remove/ Check the fuel pick up tube , tank shutoff valve, elbows along the line for clogged fuel supply line.(Occasionally a thick, hard precipitate or wax from diesel fuel can plug the line...especially in COLD latitudes!.)
The glow plugs can be checked by touching carefully with your fingers after holding the glow plug button for 15-30 seconds...they should feel at least warm to the touch. The glow plugs are heaters and can be tested for continuity with a voltmeter just the same as you would check a fuse for continuity. I haven't found an inline fuse, relay, or fusible link in the glowplug circuit of my Universal, but you can "jump" the glowplug switch/ wiring with a single wire (10ga.?) directly from the battery to the terminal on the top of one plug. I really encourage you to install an electric fuel pump (you may already have one?) so after fuel filter changes, remove the downstream hose from the secondary filter and turn on the ignition switch/ prime both filters EASY! Good Luck! I really think YOU have a fuel problem! Go real easy and careful with start fluid...easy to BREAK your engine!

[01kiwijohn]

" I have bled both bleed screws on the filter and on the injector pump. Fuels flows freely. I loosened up the fuel fittings on the top of the injector and no fuel flows out of the tube when cranking the motor or operating the fuel pump. Not even a dribble."

This being the case, it appears the problem is with the rack control, inside the pump.
If you have bled out all the air, then it should at least start and run ok.
The fuel control rack should go into "full fuel" at rest, which ensures it has plenty of juice to light up when cranked. Once running, the governor takes over and controls the rack, which controls the fuel delivery. If you have NO fuel at the injectors, then this is where the problem must lie.

[boeing1]

good advice in the above threads, are you getting fuel past your secondary filter, I had one that I installed that would not pass fuel, after replacing it again fixed the problem, also if you have a bleeder on in injector pump might try bleeding that also