Prop is very slow to cycle.

S

Skylane182H

Filing Flight Plan
Joined
Dec 19, 2024
Messages
4
Display Name
Display name:
Skylane182H
I have a few questions for all you prop/ prop governor gurus out there.
My O-470U engine has just been overhauled and hung back on my 182. A new Hartzell 3 blade Voyager prop has been fitted to it. The old prop governor was replaced with a freshly overhauled one. The engine had it's first brief start just to establish oil pressure and at 800rpm is producing 50psi. We then decided to run the engine harder to check the cycling of the prop. At first, at 2000rpm it was reluctant to cycle at all. Last night my mechanic ran it longer for about 10mins and then tried cycling again at 2000rpm. Finally.....slowly....the prop did cycle but took a long time to recover back to flat spin when the blue knob was pushed fully home. My mechanic is perplexed to say the least!
Question 1. Considering the engine is making oil pressure and oil is making its way through the crank, are we looking at a governor issue?
Question 2. Are we just fighting an air pocket in the prop hub?
Question 3. Would it be safe to break in the engine even if the prop is not cycling? My concern is running a freshly overhauled engine under no load for periods of time while we try to solve the cycling issue. The last thing we need is glazed bores.

Your help and advice is most appreciated
 
I would not fly a plane that I suspected had a prop governor issue. The reason is you could experiance an engine over speed.

My first call would be to Hartzel for advice, but I suspect the prop cable is rigged wrong or you go a bad Governor overhaul.
 
Skylane182H said:
Your help and advice is most appreciated
Click to expand...
Given its a fresh everything could be the inlet oil screen on the governor has debris or partial blockage. But since you are at the beginning of your warranty period I would be very hesitant to attempt anything outside the prescribed recommendations of the OH shop.
 
Tells me there must be an oil restriction somewhere. Sounds like the governor to me as well.
 
Oil transfer issue? It wouldn’t be a first in a big Continental.

Were the same crank and case used?
 
Last edited:
What’s your oil weight and ambient temperatures?
 
Bell206 said:
Given its a fresh everything could be the inlet oil screen on the governor has debris or partial blockage.
Click to expand...
That would be the first place I'd look. We had a similar issue with slow prop cycling and discovered the engine was making a bunch of metal that was clogging up the governor inlet screen. The slow prop was the first sign that the engine needed to be overhauled.

I sure hope the fresh o/h didn't screw anything up so bad that you need to do it again, but there may be something loose in there that is blocking it.
 
My overhaul guy had a prop or no oil pressure IDK on a IO 520. He replaced crank and it was missing plug freeze washer?.
 
Dan Thomas said:
Did the mechanic leave a plastic plug or rag in the crank nose?
Click to expand...
The rag thing happened to me years ago. Funny thing is it took a while to have the slow cycling problem. Found the rag after we pulled the prop again.
 
Clip4 said:
I would not fly a plane that I suspected had a prop governor issue. The reason is you could experiance an engine over speed.

My first call would be to Hartzel for advice, but I suspect the prop cable is rigged wrong or you go a bad Governor overhaul.
Click to expand...
I called Hartzell. The suggestion is to keep running and cycling attempts. Their first thought was a trapped air pocket in the new hub. Next could be a governor issue
 
Stewartb said:
Oil transfer issue? It wouldn’t be a first in a big Continental.

Were the same crank and case used?
Click to expand...
Same case but different crank. All the major parts of the engine….crank, cam, gears, case, cylinders and pistons were all overhauled and checked out in Tulsa, OK.
 
That seems a tad low for stone-cold oil pressure. Maybe nothing there, but just noticed that and figured I'd comment. I hope it's nothing major or nothing at all.
 
I know of a DC6 that almost ran into a 727 at DFW. Coming over one of the over passes on a a cold slick day. Was sliding done the back side tried to reverse the engines, but it only moved them forward faster. Oil hadn't warmed up yet.
 
You must log in or register to reply here.
Back
Top