Deuce Oscillating idle question

[kendelrio]

As we know, my neighbor bought a deuce recently. After mine starts and comes to idle, it steadies into a solid idle. His on the other hand oscillates. Higher to lower RPM about every 2-3 seconds. Normal? Abnormal? I have never heard a deuce do this. The only difference between mine and his (without knowing the full maintenance history) is his is a 72 and mine is a 69.....

Any help is appreciated.


(And yes, I searched the wiki, I got 151 results and didn't want to go through EACH and EVERY one of the posts..... in fact, here is the search link..... Steel Soldiers::Military Vehicles Supersite - Search Results )

 

[jasonjc]

When you find out let me know I've got that do that.

 

[kendelrio]

Will do. If no answer here, I may have to consult the oracle of Deuci... Dlawbrey

 

[littlebob]

Ken,

Has he changed the fuel filters yet? If not I would suggest changing all three first. I would also have him check to make sure the in tank fuel pump is working. I also don't know how much time he has spent doing the basics like draining the moisture out of the tank and all three fuel filters. let us know what you find out.

 

[kendelrio]

Will do LB..... Willing to bet he hasn't done any of it. Will get with him tomorrow or Sunday.....

 

[wsucougarx]

I have been told that the oscillating is due to a IP possibly going out

 

[gimpyrobb]

I hope not, my truck I just got running does this. If I bump up the throttle to 8 or 900 it smooths out. Once it warms up, I can push in the throttle.

 

[nk14zp]

Check the valves.

 

[JDToumanian]

It goes away after the engine is warmed up, right? ...It's just governor hunting, nothing to worry about. Some engines do it, others don't. It could be due to varying levels of wear, but most likely it's governor is just a little bit out of adjustment. On 2-stroke Detroit Diesel engines, this "governor gap" is easily adjusted with feeler gauge, screw driver, and wrench by removing the cover on the governor... on the Multifuel, it may be more difficult. Mine hunts when cold and I couldn't care less.

Jon

 

[cranetruck]

Check your idle rpm, it may have to be adjusted up a bit or use the hand "throttle" to increase the revs until warmed up like Jon stated.
The idle is set higher on the turbos vs the N/A engines.....
About 750 for N/A and 825 for turbos.

Edit: Added image.

 

[tjcouch]

Mine did that when the in-tank pump was inoperable . . . . the oscillation stopped after I replaced it.

 

[kendelrio]

Thanks all for the replies. I now have a direction to go!

 

[Floridianson]

Does it do it when the motor is at full temp not just warm. They require full temp to run right.
If at full temp and idle brought around 850 900 the problem is still there then pop off pressure of the injectors could be checked.