1957 Fastwin lower unit question

[Bill 1970]

I have searched the past posts, and cant seem to find an answer. My 57 fastwin is leaking oil out of either the exhaust outlet or the water intake tube. Im not sure which. Ive changed my lower unit oil and its kinda dark (black) but doesnt seem to have any water in it. I am going to do a reseal kit on it, but Ive never done one on a shift motor. Any ideas what is causing the leaking? Which seal? Ive done a seal kit on my 57 lightwin, but that was simple. Im tempted to buy a service manual for this motor, but Im not sure I need one to do a reseal. Any thoughts or tips you guys can give me would be greatly appreciated. Thanks in advance, Bill

 

[Daviet]

Re: 1957 Fastwin lower unit question

Are you sure what you are seeing is not unburnt oil/fuel coming out of the exhaust? Have you been running this in a tank or on the water? Is it black and smells of gas?
If you are going to maintain your own engine I would suggest you get the factory manual.

 

[Will Bark]

Re: 1957 Fastwin lower unit question

Does that oil have a burned and gasoline smell to it; if so, that's probably unburned oil and gas which is not a leak and is natural.

 

[lindy46]

Re: 1957 Fastwin lower unit question

If no water came out and if the gear oil wasn't milky, then you don't have a seal leak. If it ain't broke, don't fix it.

 

[jbjennings]

Re: 1957 Fastwin lower unit question

If no water came out and if the gear oil wasn't milky, then you don't have a seal leak. If it ain't broke, don't fix it.

Ditto from me!
'57 OMC's are real pieces of junk, BTW! That's why I own 3 of 'em.
BTW, synthetic 2-stroke oil will cut down on the crud, as will a little high speed running and a decarb. But nothing will totally eliminate it. Synthetic oil is supposedly more biodegradable than dino oil as well.
Later,
JBJ

 

[Bill 1970]

Re: 1957 Fastwin lower unit question

THANK-YOU all for the input. I had been running the motor on a "no wake" lake last sunday so I hadnt run it "full out" I had never seen that much of a gas/oil puddle under it before so I was really worried that I would have to tear into the lower unit, which Ive never had to do on any of my 57"s with the exception of my lightwin. Im running a heavy 24 to 1. Does anybody have an oil brand of type suggestion that might burn a little cleaner?

 

[jbjennings]

Re: 1957 Fastwin lower unit question

Pennzoil full synthetic tcwIII is usually about the cheapest synthetic oil---it burns cleanER.

 

[Bill 1970]

Re: 1957 Fastwin lower unit question

Pennzoil full synthetic tcwIII is usually about the cheapest synthetic oil---it burns cleanER.

Thank-you, JB for the advice. I will get some pennz. Is 24/1 ok for those motors, or am I running a little rich?

 

[1stgenbird]

Re: 1957 Fastwin lower unit question

24:1 is what these motors take. Others may say with the modern oil that can be reduced to 50:1 but I prefer to keep my 57 fastwin around for another 50+ years so I keep at 24:1.

 

[samo_ott]

Re: 1957 Fastwin lower unit question

Pennzoil full synthetic tcwIII is usually about the cheapest synthetic oil---it burns cleanER.

That's what I also use. You can get it at Walmart. I run mine at 30:1. Why 30:1 one might ask, well I have a 30 litre gas container and I dump in 1 litre of oil! easy calculations... And never had any problems yet...