Mcculloch Pro Mac 10-10

[kcjones]

Is it better to put a new gas tank gasket on or use RTV?

 

[svk]

How bad is it leaking? RTV doesn't last forever if it is in constant contact with fuel.

 

[kcjones]

I was taking the clutch cover off, turned it on its side, and within a minute there was a 4 or 5 inch puddle on the bench.

 

[Teemore]

I was taking the clutch cover off, turned it on its side, and within a minute there was a 4 or 5 inch puddle on the bench.

Don't rule out the possibility that it is the duck bill valve in the fuel cap that is causing the leak....

 

[kcjones]

Don't rule out the possibility that it is the duck bill valve in the fuel cap that is causing the leak....

I'll check that. Need to check the fuel line as well. Its been setting for about 6 months.

 

[svk]

Yes definitely check the spot where the line meets the tank as well as the cap before going further.

 

[Dennis Gauge]

I tried to RTV on my old PM700. Gas ate through within minutes and leaked like a sieve. You either need something that's fuelproof or an actual gasket.

 

[kcjones]

Anyone use Permatex Permashield?

 

[Brent Adams]

Use Permatex Motoseal. Yamabond 4 is Also gas resistant. So is Dirko, but ive never tried it.
As already said, check the gas cap gasket, vent valve, and fuel line where it goes thru the bulkhead. All of my gas caps leak at least a little.

 

[mogulmasher]

Yep all my gas caps leak at least a little too. As Brent said use motoseal. That's what I have done to last couple I have done. With top of tank off clean the gasket/groove of any loose debris. Leave original cork gasket in place and put a small bead of motoseal down. Reinstall top of tank and done good to go.

 

[kcjones]

The RTV thats on it is discoloring the mix. Hope none of that ran through the carb!

 

[kcjones]

It was the gas cap.

 

[kcjones]

Thanks for all the replies. Very helpful.

 

[kcjones]

Are there any alternative materials for the gas cap gasket, besides cork?