BF8A oil in the fuel issue

IFish4Tuna

Cadet
Joined
May 30, 2006
Messages
11
Hi - my 2005 outboard started acting up mid summer, but have only now been able to take the time to really look at it.

The symptoms.

1. Needing to keep it choked almost fully in order to keep it running at fast idle. Once in gear (when I could keep it running long enough to get it into gear) and under load, I could push in the choke - sometimes all the way and it would run seemingly fine. This is why I was able to put it off until end of season.
2. Noticed that when I put it up on tilt that a motor-oil/gas mixture was coming out of the carberator air intake. Not good.... This should be just gasoline. (4 stroke).
3. Even playing with the choke while in neutral, I need to keep it revved up excessively to keep it running - if I can keep it running.
4. In order to start up again, need to choke it.

So, today, I tore a bunch of it down to see if I could make a difference and see what was up...

Unrelated to the problem, I took care of these routine maintenance items:
I cleaned out the water coolant plate and thermostat, cleaned the carb out very well. The thermostat had some build up on it, but I'm pretty sure it was still functional. The pee hole was amost clogged up but was still dripping water from it. I also changed the engine oil, and inspected the plugs.

I took these photos of the rear of the engine. Should there be this much oil residue in there? I'm not sure I understand the principle of what the unit on the exterior of the rear housing (see last photo) does. It has some kind of spring loaded mechansim on it. It seems that what is happening is that excess oil is coming from the housing where the valves are and mixing into the fuel system that feeds the carberator....

Wondering if any one has any strong opinions on the cause, or if you could point me in a direction of further analysis.

Thanks, Ed
 

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gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: BF8A oil in the fuel issue

I would think that you may have a ruptured diaphram on the fuel pump if you are getting oil into the carb.
 

IFish4Tuna

Cadet
Joined
May 30, 2006
Messages
11
Re: BF8A oil in the fuel issue

Thanks for that tip. I will have to look into that. I did not realize that was the fuel pump on the outside of the housing. I have done some repairs of fuelpumps on my Yamahas, so hopefully this is as trivial.

Thanks again. Will report findings once certain.

Ed
 

JUSTINTIME

Captain
Joined
Sep 2, 2006
Messages
3,284
Re: BF8A oil in the fuel issue

bad fuel pump
bad t-stat
do you troll a lot?
 

IFish4Tuna

Cadet
Joined
May 30, 2006
Messages
11
Re: BF8A oil in the fuel issue

Well, I looked this morning. I don't see any visible tear in the fuel pump diaphram. The diaphram seem well connected to the moving parts.

Is it possible that oil is coming back into carberuator through intake manifold? when it gets tilted up? That would imply a crack in the block somewhere.

At this point is the engine throw away?

Before I started working on the engine yesterday, I had it laying on the garage floor (rear facing the floor) for the past week. When I picked it up straight to put it on my motor mount. I got a bunch of gas/oil all over my floor. Probably a 1/2 cup full. It drained down through housing and out the propeller exhaust area....
 

hondon

Lieutenant Commander
Joined
Jun 11, 2001
Messages
1,922
Re: BF8A oil in the fuel issue

Slow down!Start with general health issues.What are those compressoin numbers?When is the last time those valves were adjusted?A misfiring spark plug? Contaminated fuel?Always start with the basics before you start tearing into things.
 

kandil

Chief Petty Officer
Joined
Aug 8, 2008
Messages
567
Re: BF oil in the fuel issue

Re: BF oil in the fuel issue

Well, I looked this morning. I don't see any visible tear in the fuel pump diaphram. The diaphram seem well connected to the moving parts.

Is it possible that oil is coming back into carberuator through intake manifold? when it gets tilted up? That would imply a crack in the block somewhere.

At this point is the engine throw away?

Before I started working on the engine yesterday, I had it laying on the garage floor (rear facing the floor) for the past week. When I picked it up straight to put it on my motor mount. I got a bunch of gas/oil all over my floor. Probably a 1/2 cup full. It drained down through housing and out the propeller exhaust area....

Hi it is the way you have it on the floor face down :eek:you have 2 ears on the side and that is how you should have it stored on it's side with the tiller handle up or in upright position:) and make sure you add oil to the Motor and if you want you can change the small O ring gaskit that is on the fuel pump
 
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