50 HP Thunderbolt 74 oil leak

[rsp95]

I've been working on my boat most of the season and finally finished. Started the motor for the first time this year and everything looked and sounded fine. Approximately 4 hours later I find an oil puddle below the motor. Looks to be coming from between the the prop and lower unit (technically challenged so forgive the non techinical terms). The size of the oil puddle is slightly bigger than a credit card. Is this big trouble?

 

[corm]

Re: 50 HP Thunderbolt 74 oil leak

Hi,

That depends on if it is gear oil or unburnt oil from running the engine. LU oil will usually be clear/amber(same color of the LU oil) and thick or heavy. Unburnt residue will be thinner, milky brown and black from the water and carbon being washed out of the exhaust housing.
LU oil is trouble and unburnt residue is normal.

 

[rsp95]

Re: 50 HP Thunderbolt 74 oil leak

The color was dark close to black, consistancy of oil, thick. I remembered that when I replaced the lower unit oil, the first week or two I saw a couple of drops of oil coming from the same location. If this is trouble, how bad is it? Is this big $'s kind of trouble?

 

[Yepblaze]

Re: 50 HP Thunderbolt 74 oil leak

It's more than likely leftover "2stroke ooze" from running the motor.

Very common, and generally not an issue.

 

[rsp95]

Re: 50 HP Thunderbolt 74 oil leak

Thanks Yepblaze. I will give her a try next weekend.