Speed or lack of.

[tankie88]

I've had my 87 M35a2c about 2 years now.Just wondering,it will only do 42 MPH at 2000 RPM.Any body any ideas why it won't go faster.I thought 56 MPH was the top notch.

 

[rosco]

It will do 56! You need more RPM's -- change the fuel filters.

 

[theeDIZ]

I'd start checking things, my shop van will do 52mph at around 2200 and it's a brick!

 

[Floridianson]

I might check the no load RPM when you have the motor up to temp. Then you can work it from there.

 

[FloridaAKM]

I have the same truck you are talking about & totally empty, it will run 53-55 on a good day! Half loaded, it will run 50. but is happy running 45-47. The truck is stock from the WRAFB in Georgia & has 11,250.0 miles on it. The oil & fuel filters have been changed once, plus the tank was cleaned out by siphoning out the little junk that was in it & refiltering the diesel fuel before replacing it back into the tank!

 

[quickfarms]

Pull the strainer and look at what is in the tank. You might be suprised what you find.

 

[dmetalmiki]

I've had my 87 M35a2c about 2 years now.Just wondering,it will only do 42 MPH at 2000 RPM.Any body any ideas why it won't go faster.I thought 56 MPH was the top notch.

Time for a full service/tune up? as per T.M.s

 

[tankie88]

Fuel filters were changed end of summer.

 

[Floridianson]

And can the motor even get to 2600 in Neutral. All fluids up to Temp. raise the rpm slow and see if it will go there. Do not snap the throttle for the test.
The only other thing I can ask now is do you know the truck is in high range. This has happened before where OP's did not know about the low/high range. Why I will never figure out as it is in the TM's and on the dash.

 

[tankie88]

Right just been and had a play.Will not go over 2000rpm stationary.

 

[Floridianson]

Easy fix.

 

[tankie88]

I see,you think it's just a case of adjusting the throttle stop?

 

[Floridianson]

Yes. Just watch/mark the angle of the linkage arm when you remove it to get the tin cover off.

 

[DieselBob]

Also don't forget to check the spring in the linkage end (9) for broken coils



and the accelerator pedal stop bolt for correct adjustment.

 

[red]

Before you dive into the injection pump what are your fuel pressures? The truck needs 5psi at the fuel tank, and 32psi after the final fuel filters at idle.

If you're not getting those pressures the engine will not get full rpm range and power.

 

[Floridianson]

Before you dive into the injection pump what are your fuel pressures? The truck needs 5psi at the fuel tank, and 32psi after the final fuel filters at idle.

If you're not getting those pressures the engine will not get full rpm range and power.

I believe you could in a no load run up. The fuel required for no load test is nothing compared to the fuel needed for power pulling the truck plus load. Yes it is a good thing to check but I believe the high idle screw will fix the rpm problem. Here we are just adjusting the governer so remove the tin plate turn the adjusting screw two full turns counter clockwise and replace the leaver to test. When you find the setting for 2600rpm then remove leaver and replace the tin cover.

 

[tankie88]

I havn't been out in the cold to have a look yet.But looking at the pics in the TM's the dust cover comes off without taking the lever off the spindle.Am I correct?

 

[Floridianson]

Too be honest I am getting old and don't remember. It has been a LONG while since I had to do the adjustment so whatever it takes to get to that rear stud.
If it does not need the arm removed that would make it easer and then you do not have to do a no load just warm up the motor and wind out the gear you start in and see if it will reach 2600. If not readjust and try again till you get her there. If it goes over 2600 just let off the fuel and back her down some.