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1977 M20J Governor leaking


MooneyBob

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My governor was leaking a little since overhaul. It was totally fine before overhaul. Well, ...

Anyway, after last flight I found puddle of oil under the plane and sure enough the governor leaks much more.

I have removed it today. What a pain in the neck. Since it is too close to the firewall  I also had to remove upper engine mount bolts in order to lower the engine and remove it from the engine.

I didn't see any obvious cause of the leak. But there is a bracket that is attached and secured by the screws that hold governor's body together. So you have to remove three screws from the governor, attach the bracket and put the screws back. I suspect that could be the cause of the leak since there is probably a lot of vibration from that bracket. 

I am sending the governor for re-seal or maybe overhaul again. 

Any experience or suggestions before I put it back? Any good governor shop in Florida? I used Aviation Propellers Opa Locka before. Thanks 

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Pcu5000 not approved for J models. Spacer and gasket stack up is very important. Consider exchange overhaul for Th governor as many shops like to change a lot of hard parts plus they oveehaul costs, then it can exceed 2k. Oh/exch from a place like aircraft quality accessories is 700$. Cheapest is a flush and functional check but the last one I paid for was obviously not done or poorly done. 

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You can get the governor off without removing he motor mounts. 

You need to remove the drive pad and the governator at the same time. Remove all 8 nuts from both then pull them both about 1/4 inch apart. This will allow them to be "bent" outward for the whole thing to be snuck out. You can get it off in about 20 minuets. 

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I had the same leak problem with my prop governor. It turn out that the spacer between the gaskets was missing.

http://www.mooney.com/en/si/M20-120.pdf

This spacer is only required for the dual mag IO-360. If the spacer is missing and the governor was installed with a lot of sealant it will eventually leak a lot, to potentially cause total oil depletion in a short time.

BEFORE NEXT FLIGHT VERIFY THE SPACER IS IN PLACE. DO NOT ATTEMPT FLIGHT WITHOUT THE SPACER.

José

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8 hours ago, Piloto said:

I had the same leak problem with my prop governor. It turn out that the spacer between the gaskets was missing.

http://www.mooney.com/en/si/M20-120.pdf

This spacer is only required for the dual mag IO-360. If the spacer is missing and the governor was installed with a lot of sealant it will eventually leak a lot, to potentially cause total oil depletion in a short time.

BEFORE NEXT FLIGHT VERIFY THE SPACER IS IN PLACE. DO NOT ATTEMPT FLIGHT WITHOUT THE SPACER.

José

I have two independent magnetos. My engine is IO360A3B6. I didn’t have spacer installed. So I am assuming it is not required for this engine, right?

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1 hour ago, MooneyBob said:

I have two independent magnetos. My engine is IO360A3B6. I didn’t have spacer installed. So I am assuming it is not required for this engine, right?


You are right. The problem is that some shops assume the dual mag engines do not require a spacer like the other engines so they do not install it. The leak does not show until the prop is set to a low rpm (2200- 2400) with power greater than 50% This is the range were high pressure goes to the prop. That is why the leak will not show on a ground run. Some shops put a lot of sealant but no spacer to correct for the leak, but eventually the sealant will give up and a lot of oil at high pressure will come out. There is no warning to the pilot until all the oil is depleted and the engine seize. You can suspect of a missing spacer by looking at the right side nose gear door. If you consistently see oil drips on the door after every flight suspect a governor leak. Using a white towel rub the bottom side of the governor mounting flange. If the towel is oily suspect a missing spacer.

José

 

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