Whaler Central - Boston Whaler Boat Information and Photos

Posted by SeaLevel on 04/22/10 - 1:12 PM

Hi guys, first outboard engine, 94 Merc 90 HP, 3 cyl. Is it normal for these engines to drip fuel/oil mix from the carb throat after it has been run then tilted up? This engine was a sloppy mess when I got it. The oil tank was leaking from the fill which I replaced with the new and improved one from Merc. Everything was all cleaned up but today I noticed it is starting to get all sloppy again. I took the carb cover off after I ran it then tilted it up and I noticed a slight trickle of fuel/oil mix coming from the throat of the top carb. Is that normal for these engines? Is there a needle and seat in there that's not closing properly? Should I stuff a rag under the bottom carb and forget it?

Posted by iankeller on 04/22/10 - 10:01 PM

What's the deal with this "new and improved" oil tank from Merc you mention?

I have a 1999 90HP and it leaks like crazy when tilted up.

Posted by SeaLevel on 04/23/10 - 3:50 AM

The original had a rectangular fill door that was worthless. The replacement has a round fill neck. The plug has the dipstick attached and an expanding o-ring seal. I put a clamp around the outside of the fill neck because it looked like the neck started to expand when you tightened the plug. The plastic in this area should have been much thicker, I keep the oil level below the fill neck when the motor is tilted and keep a close eye on it. So far so good.

Posted by awayland on 04/23/10 - 5:34 AM

iankeller wrote:
What's the deal with this "new and improved" oil tank from Merc you mention?

I have a 1999 90HP and it leaks like crazy when tilted up.

I also have the same motor, same problem, I just replaced the O ring on the cap. Haven't really tested it yet. usually don't top off the tank.

What's the deal with this "new and improved" oil tank from Merc you mention?

Posted by JohnnyCW on 04/23/10 - 4:37 PM

My carbs on my old 91 115 Merc would drip a little when tilted up. It wasn't a lot but would leave about a teaspoon or so of fuel/oil in my splash well if I left the motor tilted up all the way through the night.

Posted by SeaLevel on 04/25/10 - 12:59 PM

So I take it that it's normal and not something that I can repair. I just hate to have that oil all over everything after the fuel evaporates. I guess I'll just put a rag under the carb cover and below the front of the lower cowl when the motor is tilted up. It seems to run fine and not flood or anything so I guess nothing is really wrong with the needle and seat. Thanks for the replies.

Posted by Derwd24 on 04/25/10 - 11:49 PM

If I remember correctly, some of that era Johnson/Evinrude engines had a pick up tube at the bottom of the intake cowling and the cover had a gasket on it to keep it "sealed". Anything that dripped out of the carbs when tiled up would end up at the bottom of the intake box and get sucked back in next time the engine was started (or so that was the theory). Is there anything similar on your Merc that you can see?

Posted by SeaLevel on 04/26/10 - 3:39 AM

#10

No pickup tube, no gasket. The drippage just lays in the bottom of the carb cover until it leaks through the crack into the front of the cowl then down onto the steering arm. from there it goes everywhere.

Posted by SeaLevel on 05/03/10 - 4:05 AM

#11

Well guys, here's what I did. I drilled and tapped a hole in the bottom of the carb cover for a 90 degree 1/8" NPT to 1/4" barb fitting. Then I ran a piece of oil injector tubing from the barb through the lower cowl and into a small plastic container that velcros to the transom inside the drain well. Now whatever drips from the carbs when the motor is tilted will run into the container. The vacuum inside the carb cover may also draw whatever oil is in the container and tube back up into the carb throats. Time will tell. Hopefully I can test it out later this week.

Edited by SeaLevel on 05/03/10 - 9:59 AM

Posted by HarleyFXDL on 05/03/10 - 5:57 AM

#12

Carburetors will leak if tilted enough. That is a common problem will a carburetor. If the bowls are full and you tilt the motor past a certain point, fuel will spill out. You might try running the motor a few minutes with the fuel line disconnected before putting it away.