Turn up fuel

[dirtyfingernails]

Several members have had a similar problem of hard starts but after goosing the throttle a little the engine resumes a normal idle RPM. I couldn't find the original post. To refresh memories. After sitting overnight, my deuce fires up quickly (less than a revolution). However, it would run roughly at about 400 rpm and stall if I didn't give it some throttle. Once I had oil pressure (about 20 sec) I would rev to about 1000 rpm for another 20 sec. After that, the engine idled and ran perfectly. After talking with several people, I decided to just let sleeping dogs lie and live with this idiosyncasy. By the way, all fuel filters are new, the fuel tank was steam cleaned, it has new fuel, and no air leaking into the system. However, last week we had our first cold day of the season (39 degrees) [florida you know] and the problem was even worse. So I called Memphis and talked with one of their mechanics. He said that it sounded like the fuel needed to be turned up. He told me how to do it (one turn). I will find out in the morning if this cures this problem. Driving it didn't seem to change--except now it produces smoke (blue) whereas before it was mainly clear (clean) exhaust. I know you guys say not to touch that screw without a pyro--however, this guy works on them for a living. All I can say is, I hope it cures the problem. I'll post tomorrow after I try starting her up.
Steve

 

[alphadeltaromeo]

Loping is normal on starts from what I understand. Mine does it and will even out after a bit. Even if he works on them for a living, I'd not adjust the fuel without a way of checking the results of doing that.

My 2 cents

 

[Blood_of_Tyrants]

Sounds like any cold diesel.

 

[m-35tom]

when you start any diesel with a mechanical pump, the fuel rate defaults to full fuel until the govenor limits the speed to idle. in other words it makes no difference if you crank it 'on the floor' or not. most to all the multifuels i have worked on have bad injectors. that is to say that they all do not spray the same pattern and sometimes not even a pattern, just a jet. when cold this will cause all kinds of erratic rpm and puffs of smoke. usually when warmed up some it will even out as the fuel will burn more readily. the low idle at startup sounds like a sticking fuel rate slider, i would run a couple cans of cleaner through it.

 

[M543A2]

I have a 5 ton semi tractor that had the same problem. Turning up the fuel solved it. I do not remember how many turns it took to just solve the problem, but we go beyond that on all of our trucks. Pyrometers are good, and drive with sense. Just don't floor it and keep it there for a long period.
Regards Marti

 

[dirtyfingernails]

With all these admonitions against turning up the fuel without a pyro, I have to ask. Anybody ever personally see an engine tacoed by turning up the fuel? And, what did the military do when they adjusted the fuel rate? Certainly those settings were adjusted by someone, otherwise, why have them adjustable? Just trying to understand.

 

[Militoy]

I don't recollect too much about operation of the M35 - since I haven't operated one (or an M53/M54 model) since I got out of the Army in the early 70's - but does the engine kill with a cable pull like my Goat does? I had the same kind of cold start problem, before I read through my operator's manual, and started leaving the cable "pulled" until the next restart, to prevent the fuel filters from draining back into the tanks. I realize your M35 is a very different animal than the 2-stroke Goat - but it was just a thought. BTW - very cool "flying Goat" picture!

 

[Recovry4x4]

Steve, the fuel rates were set on a flow bench then all the stuff marked or lead tagged to prevent adjustment. Thats pretty much a standard on rebuilt pumps as well and removing the lead tags or the paint they put on threads voids the warranty. With that aside I'm sure plenty of GIs cranked the fuel up on their trucks and I'd bet more than a few had meltdowns.

 

[cranetruck]

An injector cleaner may help, but it's nothing like a good hard drive to make the engine happy, my deuce idles without smoke (it has been driven) and the 8x8 idles with a lot of blue/gray smoke (has been sitting for years)...

 

[dirtyfingernails]

Well, the adjustment worked! I went out this morning and she fired right up and went to 825 rpms and ran smooth. No rough idling, no need for throttling it to keep it running. I think I'll turn the fuel down one flat at a time over the course of several days to get it as close to the original position while avoiding the rough start problem.

 

[ken]

Both my M52 qand My m35 did the same thing. Now eather of them can sit for months. And fire up and run smooth on the first try.

 

[doghead]

Ken, you say they both did the same thing (lope) but now they don't. Did you make the same adjustment? (one turn)

Could you guys be more specific on which "screw" you adjusted. (which one did Memphis Eq suggest)

 

[ken]

Yes they both would lope and stall if i didn't give them a little throttle. I didn't go one complete turn though. Now you can stand on the running board and hit the they button and they will run like they were just shut off. I think the amout you turn will vary between trucks.

 

[m-35tom]

the field method of adjusting the fuel rate is 9 psi at intake test plug

 

[cranetruck]

the field method of adjusting the fuel rate is 9 psi at intake test plug

Any TM reference for this?

 

[m-35tom]

yes, i remember the whole procedeure, but can not find the pages that were sent to me by clark truck. 9 psi at 2300 rpm and 5psi at 1500 rpm for droop screw

 

[dirtyfingernails]

Doghead,
The screw is a piece of threaded rod. It is found to the right (rear) of the injection pump (where the lines leave it). There is a "valley" there with a triangular cover held on with two 7/16ths inch hex head bolts. Mine were wire tied with a lead seal. Remove the wire tie, remove the hex head bolts, remove the cover. Now you should see a piece of threaded rod with two nuts on it. Loosen the outer nut while holding the inner nut in place. Turn the inner nut clockwise to allow more fuel in and counterclockwise to restrict the flow of fuel. The mechanic told me to turn it one turn, tighten the jam nut and try the truck. It worked great! No more start up problems. I came home this afternoon and turned it down one half turn and experienced the problem again, so one turn seems to be a good starting point. Also, I used a caliper to measure the length of the rod before I started. That way I knew what the starting position was (fairly closely anyway). Steve

 

[doghead]

I was wondering if they (Memphis Eq.) were telling you to adjust the main fuel screw or the servo pressure screw. Thanks for the good explaination.

 

[dirtyfingernails]

I just turned the one the man told me to.

 

[Jimma]

I am having similar issues. Where exactly is the adjustment on the truck to turn up the pump?. The previous owener told me that the pump was turned down and might need adjustment. Please provide some instructions someone. I have the manuals on cd but they are not with me/