1964 merc 60 6hp leaking gas from lower unit

Csamuels · Mar 13, 2013

Hi new here this is the first outboard I've ever owned, it's a 1964 I've replaced the waterpump housing and the impeller and it runs good but it leaks gas from the lower unit , I replace the o ring at the top of the drive shaft and it slowed the leak a little but now most of it comes out of the exhaust now. I would really love to go fishing soon! Any help would be greatly participated thanks.

Chinewalker · Mar 13, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

If that's what is left after you run in a barrel, then it is more or less normal. A small amount of unburned fuel comes out with the exhaust - a downside of two-stroke technology. In the confined area of a barrel, it accumulates and looks like more than it is. On open water it dissipates and evaporates quite rapidly.

However, if it is excessive, it could indicate a missfire or sticky float.

mr 88 · Mar 13, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Go Fishing !! That is normal as Chine noted,what comes out of the prop is all exhaust and gas/oil residue. Take a look at your muffler on your lawnmower or better yet a two stroke motorcycle. All the unburned fuel/oil ends up at the end of your exhaust system and does look messed up to the untrained eye.Good luck with the fishes,hook em hard.

Csamuels · Mar 13, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

mr 88 said:
Go Fishing !! That is normal as Chine noted,what comes out of the prop is all exhaust and gas/oil residue. Take a look at your muffler on your lawnmower or better yet a two stroke motorcycle. All the unburned fuel/oil ends up at the end of your exhaust system and does look messed up to the untrained eye.Good luck with the fishes,hook em hard.

But should the gas be coming out we're the lower unit meets the shaft it happens when I squeeze the primer bulb as well

Lone Duck · Mar 13, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Csamuels said:
But should the gas be coming out we're the lower unit meets the shaft it happens when I squeeze the primer bulb as well

check your float valve.

Chinewalker · Mar 14, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

If excessive gas comes out without the motor running, then you have other issues. Bad float valve would be my first guess. Could also be a bottom seal. Have you run the motor on a boat yet? Can you confirm that it runs on both cylinders?

Csamuels · Mar 14, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Chinewalker said:
If excessive gas comes out without the motor running, then you have other issues. Bad float valve would be my first guess. Could also be a bottom seal. Have you run the motor on a boat yet? Can you confirm that it runs on both cylinders?

I have checked the float it was stuck open but that was before I took the pics it was much worse I couldn't see the prop under the water and I have not had the boat in the water yet just ran the motor in the barrel I believe both cylinders are firing

Lone Duck · Mar 14, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Csamuels said:
I have checked the float it was stuck open but that was before I took the pics it was much worse I couldn't see the prop under the water and I have not had the boat in the water yet just ran the motor in the barrel I believe both cylinders are firing

I believe it is time to replace your float and valve. While you are at it maybe think about a new carb kit and carb clean.

Csamuels · Mar 16, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Csamuels · Mar 16, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

here is a video of whats going on

Chris1956 · Mar 16, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

A hole in diaghram will allow fuel to pour into the crankcase and from there into the exhaust.

Chris1956 · Mar 16, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Sorry, was distracted. The fuel pump diaghram is the one I meant

Csamuels · Mar 16, 2013

Re: 1964 merc 60 6hp leaking gas from lower unit

Chris1956 said:
Sorry, was distracted. The fuel pump diaghram is the one I meant

You were right big hole nowi just gotto find a new one I really appreciate all the help
There is a shot of my boat too 1958 crosby sled 14ft

1964 merc 60 6hp leaking gas from lower unit

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