M35 oil pressure and idle

[deuceman51]

What do you guys usually idle your M35s at? Mine right now is about 550 to 600 and it shakes really bad. speed it up to about 700 and it is smooth. Tonight I had a friend of mine who works on hercules engines tell me that the tractors idle faster and I should increase it a bit for a smoother idle to get rid of the shake. I'm assuming that all you have to do is turn the turnbuckle linkage to the petal to increase the rpm? At idle my engine oil pressure shows 25lbs, 1000rpm=50lbs, 1500rpm 60lbs. I used a mechanical gauge in place of the oil sender unit. We also took out the check valves on the side of the engine behind the turbo to see if they were ok, but I was also wondering if anyone knows which controls what. One does the engine oil pressure and the other another oil pressure in the block. He couldn't remember which controlled which and said the tractors were a little different style, but same principle. Does anybody know the correct length of the springs inside the check valves? I want to see if they compressed and need replacing. Sorry for all the questions, this is my first multifuel and I want to get it all adjusted right to keep her running top notch. I'm slowly fixing about 10 years of farmer neglect before I got the truck. Thanks in advance.

 

[WillWagner]

My turd runs 70-75 PSI cold idle, 30-35 PSI hot idle. At 50 MPH, it has 70 PSI. This is using 15w40 oil. You should set the hot idle at 800 RPM to prevent the headlights from shaking themselves to death and causing you to spend mucho dinero for replacement lights.

 

[jwaller]

750-800rpm at idle to keep from busting headlight filiments. and so it will idle smooth like it should. cummins will idle at 550-600.

 

[OD_Coyote]

Mine idles @ 750 and the oil pressure @ operating temperature is 45 idle and 65 @ 2000 with Delo 15W-40

 

[dmuchow]

Do these higher idle RPMs make a big difference in fuel consumption? I read somewhere that Diesels use about 10% the fuel that gasoline engines use to idle. I'm sure its a bit higher with multifuel though.

 

[cranetruck]

I wouldn't worry about fuel consumption at idle, it's about 1 gal/hr. The proper idle speed is 825-850 for the turboed multifuel about 100 rpm lower for the N/A engine.
It is set with the adjusting screw on the injection pump.
The oil pressure regulator is on the engine block below the turbo, correct length of the springs are in one of the TMs, not sure which one , I'll have to look it up....TM 9-2815-210-34-2-2....section 4-18.

 

[zak]

I'm sure I read somewhere, I think it was in the tb's that a low idle will damage the engine due to excessive vibration.

 

[acetomatoco]

Idle speed is recommended at 1000 rpm at any time over 5 minutes or so....that is what the hand throttle is for'

 

[cranetruck]

I think "idle speed" is defined as the engine rpm without throttle engaged, but you are correct, run at higher rpm after first five minutes of idle.

 

[builder77]

I did not realize there was an actual idle adjustment screw on the IP. Both of my trucks in current adjustment require idle adjustment with the pull lever. Currently I have have it pulled out maybe halfway to get the 1000RPM idle.

 

[m-35tom]

idle adj screw is at top rear of cover on rear side of ip, where the linkage attaches. it is a screw that goes straight down with a 1/2" lock nut.

 

[spentshell]

Should the idle adjustment be done with the engine running or off?

 

[m16ty]

I haven't adjusted the idle on a multi-fuel but I'd do it with the engine running. That would keep you from having to adjust it a little then start it and if it's not right shut it off and do it again. Just adjust it till it sounds about right and then look up in the cab and confirm with the tach of have someone in the cab while you adjust and tell you when you're right.