88 SPL lower case oil leak

[pkturbo]

I have recently bought a 1987 Johnson 88 SPL. The compression and teltale are good, and it ran fine when it was attached to the seller's boat. Now that I have it mounted and installed on my boat, I had a little trouble getting it to idle right - seems a little high at ~1000 rpm at idle. I guess I probably need to do a link & sync.
But the main issue is now that the lower case is leaking gear case oil from around the prop. I am sure it was not doing this when it was on the seller's boat. Can a prop shaft seal fail suddenly like this? What might cause it? Should I replace all of the lower unit seals, or just the shaft seals? Any and all advice welcome. See leak pic attached.

Pete

 

[Big flop]

Re: 88 SPL lower case oil leak

Check your gear lube for water.
If no water and lube is clean
that may be gas and or oil from
powerhead that did not burn.
You can also smell it and see if it
smells like gas or grease.
And a seal can just start leaking.
More likely if it's been sitting.

 

[pkturbo]

Re: 88 SPL lower case oil leak

The gear lube is not milky, as the motor has not been in the water since it was replaced. It seems to me that there is too much 'oil' leaking to be merely unburned gas oil, also it seems a little thick/viscous to be gear lube.

I didn't mention it in the OP, and you can't see it in the picture, but it is also leaking from behind the prop, not just where you can see it in the pic.

 

[boobie]

Re: 88 SPL lower case oil leak

Looks to me like unburned fuel and oil. Common in 2 stroke mtrs.

 

[Monte1961]

Re: 88 SPL lower case oil leak

Heres the thing, if you want to make sure you dont have any leaks, then drain L/U gear oil, find yourself away to submerse just the lower unit in water, apply no more than 5lbs psi, if you dont see any leaks, try and spin prop shaft and look for bubbles. Ither way, if theres a leak, you will find it!

 

[emdsapmgr]

Re: 88 SPL lower case oil leak

Usually a gear oil leak is more clear in color. This looks like unburned fuel from the exhaust. Is it possible that this engine has just started running after winterizing? If so, you will find a lot more gunky stuff coming out till all the winterization oils burn off. You can't set the idle on the trailer- it will be 1100 to 1200 rpm. Set the idle when the boat is floating normally in the water and it is in forward gear. Set it to 650-750 rpm.

 

[boobie]

Re: 88 SPL lower case oil leak

The spec for pressure testing is normally 14 psi, rotating the g/c and moving the shift rod through it's full travel.