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Old 26-12-2017, 08:38   #1
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Grease at a hole on Tohatsu 18 2 stroke.

I've just noticed a small hole on the right side, bottom, infront of the prop that is putting out a small amount of oil/grease when I pulled the motor off our dinghy. It's on the opposite side from where you change out the lower oil. When I pull the motor out of the water, lots of water comes out of the hole. I've checked the owners manual and it doesn't show any hole being there. Hasn't leaked before now. Might be another hole to suck water into the engine(it's below where the water is normally sucked in for the water pump)hence the water coming out when I raise the engine.
Any thoughts as to what it's for and should I be concerned about the grease? We've been running the engine hard recently at full throttle for longer distances that normal.
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Old 26-12-2017, 21:02   #2
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Re: Grease at a hole on Tohatsu 18 2 stroke.

I've got a Tohatsu 30 hp 2stroke that black "oil" seeps out of hole in the lower unit after it has been running at low rpms for any length of time. I assume it's unburned oil from the fuel mix. Never seen this on any other engine.

Using Amsoil synthetic at 100:1 lessens the problem some.
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Old 26-12-2017, 21:50   #3
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Re: Grease at a hole on Tohatsu 18 2 stroke.

I've been using a 50-1 ratio on my fuel. Smokes likes crazy when it first starts and then goes away. First time I've seen this but it's never since we owned it has been run so long at high RPM's. Not lots but will cover my fingers as I raise the outboard back on board should I touch it. Still runs great though. Just got worried since I'd never seen it in 3 years I've had it.
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Old 27-12-2017, 04:49   #4
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Re: Grease at a hole on Tohatsu 18 2 stroke.

We have a 2004 18 2st tohatsu and a lower unit off a much newer one. Neither has any holes other then the gear lube holes, flush hole and water intake grate.
I think you might have an issue but would definitely check your gear lube to see if it's ok.
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Old 27-12-2017, 05:43   #5
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Re: Grease at a hole on Tohatsu 18 2 stroke.

The hole Iím talking about is on the opposite side of the oil fill hole. Itís right inline with the prop on the lower housing putting it right in front of the prop shaft.
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Old 27-12-2017, 08:01   #6
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Re: Grease at a hole on Tohatsu 18 2 stroke.

Pics would help
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Old 27-12-2017, 17:14   #7
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Re: Grease at a hole on Tohatsu 18 2 stroke.

Quote:
Originally Posted by mestrezat View Post
The hole Iím talking about is on the opposite side of the oil fill hole. Itís right inline with the prop on the lower housing putting it right in front of the prop shaft.
Sounds like you have a hole where you shouldnt.
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Old 27-12-2017, 20:10   #8
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Re: Grease at a hole on Tohatsu 18 2 stroke.

What can I tell you? It's a small round hole on the opposite side from where the lower oil gets changed(left side as you look at the motor from the front).. I've been running the motor far more and at faster speeds these last few trips(4-5 miles). Not seen before. When the engine is taken out of the water, lots of water pours out of the hole. It sits about 1.5 inches infront of where the prop fits into the stern housing on the motor.
I've no clue how to post pictures or a would. Info on that would be helpful.`
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Old 27-12-2017, 22:56   #9
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Re: Grease at a hole on Tohatsu 18 2 stroke.

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Originally Posted by mestrezat View Post
......
I've no clue how to post pictures or a would. Info on that would be helpful.`
Put the picture on your computer. Reply to this thread. Then select the paper clip icon (attach). Select the picture to upload and then hit upload. Then close window and finish your message.
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Old 28-12-2017, 03:38   #10
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Re: Grease at a hole on Tohatsu 18 2 stroke.

I am thinking itís some sort of exhaust relief port. The oil you are seeing is coming from the exhaust. Just a wild guess.
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Old 28-12-2017, 04:28   #11
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Re: Grease at a hole on Tohatsu 18 2 stroke.

Are you looking at the motor from the front or back,? There is indeed a hole water drains from on the left side (port side) ide several inches above and in front of the prop. No holes right in line or just I front though
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Old 28-12-2017, 08:19   #12
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Re: Grease at a hole on Tohatsu 18 2 stroke.

As I said, I think the black oil that drains from my Tohatsu is unburned oil from the mix.

Since the motor is not VRO, at slow speeds there is excess oil that doesn't get burned. So I try to minimize the time at slow speeds, if I can.

But you say you have been running fast more/longer? That should keep it from happening unless you subsequently operate the motor at idle.

Or maybe it's something else.
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Old 28-12-2017, 10:04   #13
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Re: Grease at a hole on Tohatsu 18 2 stroke.

This is on a tohatsu 5hp, 4 stroke. Is that the hole you are seeing?
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Old 29-12-2017, 14:49   #14
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Re: Grease at a hole on Tohatsu 18 2 stroke.

Thatís the hole.
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Old 29-12-2017, 18:55   #15
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Re: Grease at a hole on Tohatsu 18 2 stroke.

Bear in mind that mechanics is very much not my thing! But the hole is definately intentional, it even bevels in in front.
It appears to me to be a drain, I doubt it is connected to the gear oil reservoir. It seems very low to be involved with the fuel.
My guess would be to allow water to drain from the prop.
Hopefully someone more knowledgeable will offer a solid opinion now that they can see the pic.
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