minmic inj. pump

[willy wagon]

on my super major with the minmic pump the engine does not always stay at a constsnt spees. sometimes the idle will creep up. or if you speed it up , then slow it down it does not always slow engine to where it should. yet it starts and runs great otherwise. could it be the govenor? is it safe to take the back plate off the govenor housing, or will pices fly everywhere?

[Brian]

Have you checked/changed the oil in the governor? Should be done every time you change the engine oil.

[Pavel]

Not sure if this will help.
My FMD had a similar problem, even though it does not have a minimec pump.
I found that the friction disc [under the fuel tank] on the speed control lever was loose. Tightening that cured the problem.
Pavel

[willy wagon]

i changed the oil. what was in there was not very clean. it seems to not always slow down are running at higher reves even though the throttle level is pulled back. just like the rack or govenor controls are sticking. cleaned are put some oil in where the rack is. would like to pull the plate off the govenor end of the pump but am a little unsure of doing this.

[Brian]

Check everything else first before touching the pump, especially if you are unsure. You can cause expensive damage if you are not careful and really need a dust free room to do it.

If you are loosing power/revs have you replaced the fuel filters and checked the filters inside the lift pump and in the fuel tap? Blockages in any of these can give the problems you report.

It may be a pump problem in the end and if it is, it is unlikely that it will be in the governor, more likely a sticking rack. Taking the sideplate off and giving the works a good dose of WD40 is a good plan but remember to keep things very clean indeed.

Another thing that I have found works very well is a litre of Automatic Transmission Fluid mixed in a couple of gallons of diesel and run her for a while on that.

[willy wagon]

yes fuel filter was changed. it seems to me the rack is just a little sticky. it moves but maybe not as freely as it should. the guy at injection shop said run synthetic oil in pump for a while. tomorrow i hope to run it with little plate off pump and see if rack sticks when throttling back.

[Brian]

OK, you changed the fuel filter but did you clean the other two? The one in the tap and the one in the lift pump. The new formula diesel can clean the system and block these filters.

Synthetic oil will clean the governors but will not help with the rack as it does not go into the pump, only into the governor housing.

The rack and pumping elements are lubricated by diesel, if she has not been getting enough because of semi-blocked filters, there may not have been enough to keep rust away and cause the sticking. That is why I suggested the ATF/diesel mix as this will clean and free off sticking parts in the main part of the pump without you having to dismantle anything.

[willy wagon]

i ran it the other day, it is most definately the rack sticking. i had the little plate off the side and it did not want to return to idle when trottled down. ran some atf in the pump for 10 minuites. now it has synthetic. however did not realize there was a filter in lift pump, shall clean it, the one in the sedement bowl i have cleaned. thanks for all the info.

[Brian]

I would not run synthetic oil in the pump. It may affect the old seal, I am not sure about that having had no experience of the oil with old seals in the pump.

The ATF needs to go in the diesel and be run for a few hours. The rack is lubricated by the diesel, not the oil in the pump. They are two separate compartments. You may find that, if the seal fails, you get lots of diesel in the governor housing.

I run ATF now in all my older diesel engines and petrol engines, mixed with the diesel to add lubrication for the pump when using low sulphur fuels.