Honda 7.5HP Four Stroke - Oil Leak

TonyinPA

Cadet
Joined
Jun 10, 2013
Messages
24
Hi Guys:

I'm new to the forum. I'm trying to help my brother in-law out with his 1985 7.5HP Honda 4-stroke.

He bought this 2 summers ago used from the original owner that took excellent care of the motor and regularly had it professional serviced.

Under the cover, the thing looks brand new.

At any rate, when my brother in-law took out of storage from the winter this year and ran the motor, he noticed oil had leaked out and was dripping on the side...

He noticed the oil dripping where the red arrow is pointed in the pic:

P1100467.JPG

He took this to a local Honda dealer (not same dealer as original owner) and asked them to replace the water impeller and check on the oil leak (Impeller replacement unrelated).

The dealer replaced the impeller, then told him that it would cost him $1000 plus as there was a seal gone bad internally and leaking oil.

He picked the motor up over the weekend and this is where I have got involved to try and help him out.

We put the motor on a stand, ran it for awhile and found it dripping some oil out from what looked to be the top of the motor under the fly wheel.

I pulled the flywheel to be able to look better and also found the attached illustration online.

0100.jpg

P1100463.JPG

I have (2) questions before I proceed further...

1) I'm wondering if the oil seal item 10 is a common part to fail on a motor of this age...I am thinking this is the area of the source of the oil leak... If this is the case, is it as simple as taking the top nut of and pull the seal out with a pic or something like that? I see the part is only $10 online various places.

2) Could this be something as simple as too much oil being added? Before we go further, I am thinking of draining some oil from the engine and running again. If we try step 2, would it be safe to spray some de-greaser and warm water to clean off the existing oil to make the leak easier to see where it is coming from?

Appreciate any advice guys...trying to get my brother in-law back into the walleyes....

Tony
 

TonyinPA

Cadet
Joined
Jun 10, 2013
Messages
24
Re: Honda 7.5HP Four Stroke - Oil Leak

Hello Guys... Couple updates.

I don't suspect too much oil in this unit anymore.

Reason I inquired about that is that the dipstick didn't have a full line on it.

Just markings from 100-800.

I was able to find the owners manual on-line off Honda's website and it does confirm to fill it to the 800 mark.

I was wondering if anyone had experience changing that upper oil seal?

I've got the fly wheel off, the upper bracket pulled off and will be getting a 30 mm deep socket tonight to remove the nut that holds the timing pulley on. I was planning to use an impact on this, is there another way to hold the shaft from spinning?

Once I remove that nut will I have to pull the timing pulley off with a puller?

Is there an interference fit on this? tapered fit? keyed fit?

I also found a picture of the oil seal item 10 on the diagram.

It appears to be a rubber seal....considering this seal is sealing against something that spins while running, and the oil seams to be fogging inside the cover (in addition to the stream that formed coming from the top)...I banking on this being the source of the oil leak.

Hopefully this seal will come out easily with a pick..

Appreciate any help for guidance on this one.

Thanks.
Tony
 

TonyinPA

Cadet
Joined
Jun 10, 2013
Messages
24
Re: Honda 7.5HP Four Stroke - Oil Leak

Well, I was able to get the nut off the timing pulley pretty easily with my 1/4" impact and 30 mm deep well socket by holding on the timing pulley with a piece of leather and oil filter wrench.

Timing pulley was a loose key fit.

Pulled that and have confirmed that the oil leak is coming from the shaft oil seal.

It's cocked off to the side and bunch of oil laying on top of it.

Unfortunately I believe this is going to be a very difficult fix.

Have to pull the motor, pull the crank case cover, then pull the caps off the connecting rods to release the crank to be able to slide on the new seal.

I see why the dealer quoted a very high price to fix!

It's frustrating as the oil seal is only a $10 part....
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,509
Re: Honda 7.5HP Four Stroke - Oil Leak

A bad $10 gasket can stop a $100,000 race car, too...
 

TonyinPA

Cadet
Joined
Jun 10, 2013
Messages
24
Re: Honda 7.5HP Four Stroke - Oil Leak

A bad $10 gasket can stop a $100,000 race car, too...

Or bring down a space shuttle for that matter...

I work with industrial high speed rotating equipment used in the oil gas business for a living. That saying that things are only as strong as the weakest link comes to mind often. A lot of things have to work right...even the little stuff.

Got the engine pulled, crank case cover off, and crank pulled.

As suspected, it was the upper oil seal...

New parts on order...with any luck hopefully I can get it back together next week.

P1100469.jpg

Tony
 

novaman77

Recruit
Joined
Jul 17, 2013
Messages
4
Re: Honda 7.5HP Four Stroke - Oil Leak

Thanks for this info, saves me a lot of work. Mine is leaking so bad it's running through the case onto the exhaust and choking the motor out with smoke and leaking out the side of the case through a small hole. Makes me looked like an oil tanker run a ground. Thanks again.
 
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