Small engine help

I dont know where to turn. I have a kohler 20 horse CV 624 motor from a lawn mower. The rod broke and I replaced it. It now startes but revs so high immediately I have to shut it down because I am afraid it will blow up. I adjust the idle screw and it did fine for a minute then went bacl to the high idle. I adjusted the govenor per the manual and this did not help.

Any advice? I tried to not disturn the internal govenor when I tool the old rod out. It looked like a plastic gear of some sort. To be honest,k I dont 100% understand how the govenor works at least the internal portion.

The govenor and idleing worked fine before I replaced the broken rod.

I am at a loss. I appreciate any help!

Reply to
stryped
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Not fully cognizant of the particulars of that engine but I'd guess you're missing or misplaced the throttle return spring and instead of holding the throttle position towards the closed position you're forcing it full bore on and thereby defeating the governor.

I did it once on a B&S here...between dis- and re-assembly forget the exact throttle linkage and the spring looked like it naturally went right there and so... :)

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Reply to
dpb

I'm almost certain that, one way or another, you've screwed up the governor.

It could well be that when the rod broke it took out some part of the internal governor with it; if that's the case then even if you faithfully rebuilt exactly what you started with, you'd still be screwed.

I don't know the particulars of small engine governors, but in general they have some way of measuring speed (either centrifugal or by wind resistance), and when the speed is high they back off the throttle. Whatever is in your engine, that's what you should be able to see.

A factory manual on the thing would probably be a huge help, and may be available on the Internet. I'd start by matching what I have with what the drawing says I should have, part by part. If that didn't bear fruit, I'd call an acquaintance of mine who does small engine work when he's bored or feeling generous, and see if he'd look at it.

Reply to
Tim Wescott

ttdesign.com- Hide quoted text -

Here is the manual.

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I looked at the plastic gear before assemply and it looked intact. Is there a way to tell if it is internal or external or even the govener at all without taking it apart?

Reply to
stryped

I did that once, the governor was not re-assembled correctly. Look on page 82:

"3. Move governor lever toward carburetor as far as it will go (wide-open throttle) and hold in position.

  1. Insert a nail into hole on cross shaft and rotate shaft counterclockwise as far as it will turn, then torque nut to 6.8 N·m (60 in. lb.)."
Reply to
David Courtney

On 5/4/2012 1:48 PM, stryped wrote: ...

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Nicely done manual...

Did you note the reassembly to rotate the governor cross shaft and ensure it stayed in position while setting camshaft position? I'd guess that's one place things could have gone south.

As for outside/inside, doublecheck the linkage adjustments and spring locations -- as noted in my earlier note, just a small boo-boo there can have major ramifications.

I have a sinking feeling you're tearing this puppy down again... :(

Reply to
dpb

Yes, I think it basically said to rotate the shaft so it was touching the cylinder. I believe I did that.

Will disconnecting the govenor on the outside entirely cure the high idle and if so I can pretty much conclude that the govenor is the cause?

By the way, I adjusted the govener to no avail. However, looking in that manual I found conflicting info on adjusting it. To make a long story short one section said to turn the screw clockwise and another counterclockwise if I am reading it correctly. I turned it counterclockwise but it seemed as far as it would go and did not turn.

Reply to
stryped

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As David notes in his response pointing out the same area, did you physically restrain it to be in that position going forward to ensure it stayed there as instructed?

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If it's wrong, I expect it will have essentially no effect externally.

If verified the linkage is correct and aren't physically forcing the throttle in full-open position, I think the conclusion almost has to be the internal positioning is wrong.

It might not run well w/ a small misadjustment, but the full-bore, flat out rev'ved up means the governor ain't...again assuming the throttle isn't being held open.

Does it rev back if you manually close throttle or can you not get the throttle to close?

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Reply to
dpb

stryped wrote: ...

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What you have here is that the engine is _not_ idling. Idling is when the throttle butterfly is closed. Your engine is running with it wide open.

The basic speed mechanism is that the speed control lever pulls on a spring which is attached to the carb throttle. More spring tension at higher settings. The governor pulls back on the throttle. The engine runs at the balance point of these 2 forces (governor & spring). (I know dpb said it was the other way around, but I've never seen one that worked that way.)

In your case, the governor is not pulling back and the spring is pulling the throttle wide open. Disconnecting the governor will not tell you anything.

Bob

Reply to
Bob Engelhardt

The mechanical governor looks similar to the one on my Honda mower. The plunger on the plastic geared governor pushes on an internal lever inside the engine. That lever turns a shaft that comes out of the engine and rotates the external governor lever arm on the outside of the engine. The internal governor lever arm is fixed to the shaft, but the external one clamps on and can be rotated. It=92s important that it=92s clamped in the right position or the internal governor lever won=92t make contact with the plunger. You might have to reset and re- clamp the external governor lever arm so that the internal lever makes contact with the plunger. Otherwise the governor won=92t do its job.

Next time, etch or scratch a line on the shaft and the external lever so that you=92ll know the right position upon reassembling the engine. I=92ve also found that it sometimes helps to take pictures of carburetor linkages with my digital camera before taking apart unfamiliar things.

Reply to
Denis G.

That paddle wheel thing is probably the oil splasher, and not part of the governor. (Although I have seen engines that incorporated that into the governor mechanism. A typical governor can be either air-operated off the flywheel fan, or a form of the ancient flyball governor, ie. a centrifugal weight often driven off the camshaft.

Jon

Reply to
Jon Elson

Sure. First thing is to take over complete control of the carb throttle, and check that this works OK. If the throttle behaves normally, then you can even use that to rev the engine and observe the governor operating against a spring when it senses increasing RPM.

Jon

Reply to
Jon Elson

It starts reving immediate lfter started and is hard to start and then run in front of the motor to watch the carb.

When I put the oil pan back on I had the engine laying down where the oil pan was on top. I ensured the internal goener lever was touching the cylinder then put the oil pan down before torquing the bolts. However, I did not restrain anything.

What causes the internal governer arm to move? i know that plastic govener gear attached to the camshaft, but not sure what actually moves the arm?

Reply to
stryped

Sounds like the fork on the governor gear has come loose and it's not working now. You will have to pull it back apart and reset it.

Yes it is a plastic gear.

The plastic gear turns a small shaft with weights on it. The weights in turn move a collar which the fork rides on and that turns the shaft that comes out of the engine.

Reply to
Steve W.

manual.http://www.kohlerengines.com/onlinecatalog/pdf/sm_24_690_07.pdf>>> I looked at the plastic gear before assemply and it looked intact. Is

Actually disconnecting it will cause it to rev out of control. The governor is what stops it from revving up.

Reply to
Steve W.

What Jon is saying is to disconnect the governer from the carb so that only you can control the throttle position. Then as you move the throttle you can observe the governer arm, which is disconnected from the carb, and see if it moves in the right direction, or indeed if it moves at all. Be sure that the throttle is set for low speed operation before trying to start the engine. This may mean the the butterfly must be disconnected from both the throttle control and the governer. Eric

Reply to
etpm

Well. today I could manually rin the thing by hand. The problem is when I rev the engine and then immediately pull the throttle into a lower position, the throotle does not always come back to the low speed position. I am assuming this means it is the govenor? If so I guess I have to take it back apart. However, how do I ensure the internal fork is making the correct contact with the gear?

I may be fightenign a losing battle. It ran but now it is smoking. Something it did not do before. I have no idea why. COuld it be becasue I re used the same pistion rings when I replaced the rod?

Reply to
stryped

On 5/5/2012 10:34 PM, stryped wrote: ...

The manual had a procedure outlined, didn't it?

Depends on whether it did other damage to score cylinder or how badly worn it was. Did you ensure the rings were installed so the splits all were distributed around the radius rather than aligned?

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Reply to
dpb

Yes. The cylinder was actually in spec of a new bore. I rotated the rings about 120 degrees apart.

One thing I did notice was the cylinder I had to take off the head on had oil leaking down it. The cover was on so I could not see exactly where it was coming from. Could this be from the head gasket?

Reply to
stryped

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