Rebuilt fuel pump leaking

[SgtKish]

I finally got this thing running after finding out it was the old braided copper plug wires were grounding out on the head. Now after she started running for about 10 seconds she started loosing fuel to the carb fast. Then I saw the mechanical pump I rebuilt is dumping fuel out of those to rectangular holes that have the hair in them. I suppose it's some type of pressure  release/ filter not really sure to be honest, but the fuel is leaking bad there. All I can think of is the new neoprene baffles just ripped and its escaping that way to the 2 square holes. Any ideas on what's going on and any suggestions on the right electrical pump I can use instead of messing with this one again?

[SgtKish]

The 2 square holes on the fuel pump? Anyone know why fuel is dumping out of them?

[Outsider]

My best guess would be the diaphragm has a hole in it.
Steve
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[coreyelliott]

I agree with Steve.  A hole in the diaphragm or some other reason that it's not sealing correctly.  Also, if my memory is correct, if you have fuel coming from the vent holes this means you could have fuel going into your crankcase.

Corey

[emptyhead]

Did you rebuild the pump with a no’s kit, if so the ethanol will eat right through those old pump kits have to get a modern replacement kit from a place like then and now. Good luck

[SgtKish]

I rebuilt it with newer materials, not the nos stuff. So worst case scenario if fuel got in the crankcase? Should I drain the oil? Will the oil separate like water from the oil, or just all new oil. I put an electric fuel pump on and that's working, but now I burnt out my ground cut off switch for some reason. I used this 4 ga wire for the ground, but it consisted of a lot of thin copper wires. I feel like trying to start it so much is making it too hot on this type of wire. I'm going to try a new thicker wire and see if that works. Any idea on why that ground wire is getting so hot?

[emptyhead]

Usuall that’s indicative of a bad ground connection. Make sure it’s making good contact.  Looks like you going to have to drain the oil. Must be a hole I. The diaphragm somewhere. On the pump.

[8683jb]

Emptyhead is right on the ground - you can't have too much ground or too good of a ground! As far as the oil goes, check your oil level and if it’s only a little high, the fuel will evaporate from the oil when the engine is run. The large radial aircraft engines often used fuel to dilute the oil to help with starting in cold weather. After the flight and before shutting down, you would activate the dilution switch for a prescribed amount of time, depending on how cold it was supposed to be on the next start-up, adding fuel to the oil in order to thin it. For the next flight, after the engine warmed up and was run at operating temperature, the fuel would evaporate and the oil would return to its normal viscosity. I’d run it unless the level is really high from a large amount of fuel or the oil is so thin it runs off the stick like solvent.

Jon

[spillmk1]

I rebuilt it with newer materials, not the nos stuff. So worst case scenario if fuel got in the crankcase? Should I drain the oil? Will the oil separate like water from the oil, or just all new oil. I put an electric fuel pump on and that's working, but now I burnt out my ground cut off switch for some reason. I used this 4 ga wire for the ground, but it consisted of a lot of thin copper wires. I feel like trying to start it so much is making it too hot on this type of wire. I'm going to try a new thicker wire and see if that works. Any idea on why that ground wire is getting so hot?

I don't think 4 gauge is big enough.
I used 2/0 wire for my battery/starter circuits,
4 gauge good for about 75 amps.
2/0 wire good for about 145 amps.
Stranded wire is fine.
Size matters 

Can you smell gas in the oil?
Usually pretty easy to detect.

Keith

[SgtKish]

Ya I drained the oil and replaced it to be safe. If smelled bad of fuel, and it ran like thicker solvent but very thin. That's solid intel on the fact that the engine will burn it off for the most part. I had a guy tell me once his m37 did the same thing with the fuel pump and his engine made a load bang, and his oil pan puffed out like a metal bloon. Not sure about all that, but it did scare the hell out of me enough to just drain this oil..lol. I changed the ground wires and the thing actually started and ran for 20 min. Man does it drink fuel. I have been through every system on this thing to get her to start for the first time, and now shes running nice. The only 2 things now is I haven't adjusted the clutch yet so she wont go into gear. So I have to figure out how to adjust her tomorrow.  And when I take my foot off the clutch shes making a high pitch whine noise from what it sounds like is the PTO area. I dont know if this is a normal sound, but I doubt it. I rebuilt everything on it but the one bearing that holds the main gear that meshes up against the transmission.  So my luck that bearing is bad and making that noise. Does that sound about right, or is it something else going on here? I replaced all the bearings in both the trans and transfer case. Solid information here guys, thank you for coming to back me up here. I have spent 12 months rebuilding her from the worst possible shape, and now she almost looks new again. I wish I could figure out how to post pics. I would make a post if all the pics start to finish to show everyone.

[spillmk1]

Glad you are getting her sorted out!!!
And yes....as I said before....they are thirsty!!!

As for the noise, is the PTO out of gear or in gear when you get the noise?

Assume you topped off the oil in the trans.....just asking...I have to ask myself
more obvious questions as I get older.

You're getting there!!

Keith