IP cutoff rod.....having issues!!!

[airmech3839]

Have looked through some searches and have seen some stuff on hard starting but I am having some difficulty that I think is related to the cutoff rod on the IP. I do have a small returnline leak so that is half the problem.....I was driving to work in the beast and stopped for fuel......shutdown....then went to crank back up......it turned over but no go.....checked cutoff linkage to make sure the rod did not get stuck out.....it appeared to be in but I went ahead and pushed it in by hand at IP and it didnt budge so its in.....I scratch my head a min....trying to think this through.......opened drain cocks on bottom of filters and the one on top to insure no vapor lock while accy switch was on....got fuel so I tapped side of IP at rod lightly.....got in and it fired right up........huh....got to work.......would not shutdown cause I could not pull cutoff handle......had to pop hood and do it the old fashioned way and it was so stuck in I had to use a pair of plyers to force it to come out enough to pull cable to shut it down....I am at work now and I have tools here....just hoping I can get her cranked tonight....I would rather work on it in the daylight in the morning at my house!!! Any thoughts...just sounding off....I will take what rolls....I think it is the rod and or that part of the IP that is the problem....am I right???

 

[Keith_J]

Pull the cover for the engine stop and move the control rod back and forth. It must move freely. The bearing which causes the problem is wet with fuel on the inside, fuel under pressure. And engine oil on the other side without any seal! That means very tight tolerances, under 0.0001" diameter clearance. It gets dirty, corroded and then sticks.

It can be cleaned with minor disassembly but you need safety wire to refasten the screws and a replacement o-ring. If you are indeed an air mechanic, these should be in your tool kit.

Take a photo of the assembly so you know how to put it all back together. Resist the urge to take the assembly apart, acetone or MEK might work. I used Pro Shot Copper Solvent IV as it works better on diesel goo than anything else. Yes, it is a gun cleaning solvent

 

[airmech3839]

Can it be removed and worked on on the bench or is it an under hood job? Where to find o-rings??? I have the toolage and know how to break it down and reassembale....just don't want to take apart something that I don't have or can get parts for....

 

[airmech3839]

Why yes I am an aircraft mechanic...... is there an IPC for the IP???

 

[littlebob]

I'm looking for the reply I got when I had the same issue. Basically follow the stop cable till you get to the IP and there is a cover(flat plate) with a few screws that you remove to see a little arm to push back that is stuck. It all makes sense once you take the cover off if thats your problem. Never leave the engine stop pulled

 

[BugEyeBear]

....Never leave the engine stop pulled

I've always suspected that leaving the engine stop pulled while parked was a bad idea.

I've seen lots of guys who leave their engine stopped pulled so that it is in the desired position for doing a hydraulic-lock check prior to starting.

But once I noticed that nice polished engine stop shaft on the IP I decided to ALWAYS push mine back in. I didn't want it to stay exposed & start to corrode.

 

[Goose2448]

It sounds like the rod might be bent.

 

[Keith_J]

Yes, this is easy to do with the IP installed. A mirror might be handy to visualize.

Just remove the cover with a regular screwdriver, then move the control rod. If stuck, CAREFULLY remove the hitch pin connecting the control rod to the arm, then cut the safety wire and remove the two screws. Have a small pan handy to catch the 2-4 ounces of diesel in the head and remove the control arm, keeping the arm end down to prevent losing the little control collar pawl as it is loose in the collar shaft.

The o-ring is standard size, any good hardware store should have a replacement. Only needed if the old one is cracked etc, look under magnification. This o-ring is static, it does not contact the rotating shaft.

When reassembling, a tiny speck of grease in the pawl hole will keep the pawl horizontal for reinstalling. You need to align the pawl to the slot in the control collar, deep inside the hydraulic head.

This control lever needs to freely turn in the housing, ANY resistance will cause problems because the throttle is opened by spring force and closed by the governor force. The position of the accelerator pedal just controls how much spring force there is to lift the collar.

The TM for this is 9-2910-226-34. Pages 3-86 of the printed manual, Page 132 of the pdf available under the Resources tab here at SS.

There is no danger leaving the engine kill handle pulled, none at all.

 

[airmech3839]

I will post findings hopefully in the morning.......It fired up fine for ride home but locked up in the run mode and had to do the plyers trick to get it to shut off...... Will try and post some pics too... Thanks everyone for the input...

 

[Keith_J]

Definitely remove the cover and clean the engine stop plunger, it should slide easily. It can only pull the control collar down by pulling the control rod to the rear.

 

[airmech3839]

Ok here it goes....I useally leave rod pulled...and I never thought it was a problem...maybe it is...rod looks a little pitted...also I think the rod is slightly bent.....don't know if you can see it in the pics I took...I am not gonna have time to tear into it today...now that I know it is an issue it will be easier to know what to do when it gets stuck.... What does one do about a bent rod?? can it just be swapped out??? Where is best place to find one....anyone got an extra one...or the whole assy??

 

[Keith_J]

Yes, it looks bent. Easily swapped, see that brass hex nut? Loosen that, then remove the cover to slip the head off the control rod end.

You might try loosening the nut just a bit, should reduce packing friction. The seal there keeps dirt out of the engine oil. That section of the IP is lubricated by engine oil.

 

[airmech3839]

Where are they found??? Who carrys them and will I have to change the assembly or just the rod??

 

[Keith_J]

It is very easy to repair. Disconnect the stop wire and unscrew the big nut on the cover. It should come out, if it hangs up, remove the two screws securing the cover to the pump. This is all engine oil wetted and will not leak. But do not start the engine, this will make a mess plus you will have no means of shutting the engine off unless you manually pull the control lever back.

The wire fitting on the back end of the rod is secured with a small cross pin, drive it out and the fitting comes off, allowing replacement of the sealing o-ring. This is a dynamic seal, sliding on the stop rod. Replace this o-ring, clean the shaft with steel wool and straighten in a brass-faced vise, using brass hammers if necessary. Polish again with steel wool and coat in engine oil.

No need to replace unless it is broken.