550 massey diesel keeps losing prime on injection pump

I have a 550 Massey with a 354 Perkins diesel. The fuel injection system keeps losing prime.

When this thing looses prime I have to bleed the entire system including at least 3 injectors just to get it started.

After it starts it runs fine doesn’t miss or smoke.

Come out next day and it may need a complete rebleed to start.

I first thought I had a bad fuel lift pump…Not the problem

I then replaced my fuel line thinking it was collapsing since it was in poor shape…wasn’t it.

I’ve changed fuel filters thinking I might have a slight leak… not it

There is No diesel showing up in the oil nor do I have any leaks that I can find, believe me I’m looking hard everything is dry except where I bleed the system.

I keep thinking there should be a check valve somewhere in the system that is allowing the system to bleed off but there doesn’t seem to be one in the system.

When I bleed the system using the manual lever on the pump I get a good strong flow of fuel and the system bleeds rather quickly except for the injectors which requires turn ver the engine until fuel comes out of the lines.

frankly I’m at a loss any ideas?

I have a MF 550. There is a check valve attached between the mechanical fuel pump on the back side of the engine and the fuel line coming up from the tank. The check valve has a little steel ball that rises when fuel is coming up and going through the mechanical pump. The problem I had was a wad of soybean chaff got through the screen in the sediment bulb, came up the fuel line and got stopped at the little hole in the check valve. The wad just wouldn't pass through as the hole is so small. I even replaced the fuel pump and upon reassembly I looked into the check valve and saw something brown. Bingo!!!!!! Was an interesting problem because sometimes the combine would run for 10 - 20 minutes until the chaff floated up and blocked the hole. Wait 20 minutes and sometimes it would start and run for a while. Then quit again. I believe the screen filled pretty full in the sediment bulb. Then the mechanical transfer pump actually sucked the screen down and let the chaff pass through. When I took the sediment bulb apart the screen was displaced. Hasn't happenned since. I do clean the screen yearly now. Good luck.

Hello andy r

Thanks for your reply.

My combine must be a couple of years older than yours because my combine never had that little valve that you speak of.

I went to my Massey parts book and it appears that that valve mounts to the inlet side of the fuel lift pump and sets between the pump and the hose and was added after serial number 2387 04895.

Massey evidently put out a service bulletin on the valve (bulletin # 81-22) but evidently my combine was missed buy only a few numbers on the serial number

I may need to install a valve and it may fix my problem.

But my combine has been running without it since day one so I don’t know if my machine is a fluke or the valve was to fix a problem that would occur over time.

My machine only has around 1600 hrs on it and has always been parked in the shed

*I have a question for the board I live in southern Illinois and ALL of the Massey dealers are gone from my area

The nearest dealer is 83 miles away one way. The place is lacking in many ways and I would like to find another dealer that would send parts through the mail.

Do any of you know of a large Massey dealer with a web site that is willing to send parts through the mail.

It sound like I may need to order that valve.

Any other suggestions?

we had that problem on a 510 but it was the check valves in the lift pump, the pump will pump fine but will bleed back if the checks are bad but you said you have eliminated that, check fittings from the inj. pump to the lift pump, make sure they aren't sucking air. Probably a good MF dealer closer but Van's Imp by Hull, Ia. carries alot of parts on hand and will ship if you have a credit card. Ph.712-439-2641, Shoup also has some Massey stuff.

my 510 started doing the exact same thing last fall. i'll have to check into the suggestions here. i even put a check valve down by the tank but that didn't help. its been a race to see if the fuel cooperates before the battery dies.

My 750 had the same type of problem this past harvest. Finally took the sediment bulb assembly out of the bottom of the tank and ran a wire through it. Must of been something in there, because it ran fine after that.

Any AGCO dealer can get you massey parts now

Rudolph Bros.,Boonville Indiana,absolutley excellant!If it has the cartridge type filters like the 510s and some 750s its the little o-rings under the center bolt that holds the filter assembly together that will cause this problem,even when replaced "new",lots of times 1 o-ring won t seal up.Iv e sometimes doubled up o-rings to seal this spot,one instance had to put a wix conversion on a 510 to cure it. my 2cents,good luck.

I just went through the same problem with my 550 combine. After tightening all injection lines and fittings, changing fuel filters, doubling up the rubber washers, cleaning sediment bulb, replacing lift pump, & cleaning lift pump, I still had the problem which worsened, going from having to bleed it every morning, to every time it was shut off for a couple of hours. One morning I looked down on the injection pump and saw some wetness from fuel around and under the round disc on the top side of the pump, facing the fan. I turned it in 1-1/2 times by hand then tightened it with a wrench. Problem solved! and have not had to bleed it since. It's amazing this was loose for over 100 hours of operation without showing any signs of fuel leakage. I hope this post helps someone else someday.