7.5 Johnson 1958 AD12 Hose - Oil Line question

SPK

Seaman
Joined
Nov 21, 2010
Messages
55
Hello again,
Still working on the old Johnson and making steady progresss. I have had it out on the water with varying degrees of success lately. The fuel /air lines have been replaced and the tank has great pressure. I have of late noticed some misfiring and so have removed the plate on the flywheel to look at the coils. They look very clean and dry with no evidence of discoloration or cracking.This morning I was checking things over again and I noticed a hose on the side of the powerhead[obviously the original as it was painted "Holiday Bronze"] and when I checked it with my hand to see if there were any breaks in it, it broke off at its lower end. The rubber line just let go and I can see that it is rotten. Looks like it might be a bit of a tight spot to work in for replacing but I am ready to give it a shot.

The part number is 204189 and it is the "Hose - Oil Line" according to the parts book.
It goes on to two nippples, part number 303423 and is held in place by two clamps part number 303473.

Question: What does this line do?

What is the inside diameter of this line? I still have some fuel resistant tygon line left over from my carb repair if it would work as a replacement.

Would zip ties hold it in place on the nipples that are presently there on the powerhead?

Lastly, as this rubber line was obviously cracked, what impact if any would that have on how the motor has been performing?

Again, thanks for your support on my past posts and I eagerly await your help with this new issue.

Sean
[Lindsay, Ontario]
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: 7.5 Johnson 1958 AD12 Hose - Oil Line question

Hi Sean,
That is a recirculation line - it moves puddled fuel/oil mix to the top main bearing area to give extra lubrication and (in theory) get burned up on the way back down.
It could cause a lean condition if it is compromised. I think you need 1/8" ID fuel hose to replace it with. Zip ties should work...
- Scott
 

SPK

Seaman
Joined
Nov 21, 2010
Messages
55
Re: 7.5 Johnson 1958 AD12 Hose - Oil Line question

Thanks so much for your information. I have replaced this line with 1/8 inside diameter fuel line and it is now secure. I have not retested it on the water as of yet.

What type of engine performance might I expect as this line was compromised?[it was rotted]

Would it be a WOT issue or an Idle issue?

I seemed to have been experiencing problems at troll or idle speed [misfiring]and then when I went to a higher throttle setting the engine would not immediately rev up - seemed sluggish.

I have no problem in starting the motor and the coils look great. Been using SeaFoam in the fuel.
Your thoughts?
Thanks,
Sean.
 
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