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Oil output

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schleppy

Member
Hi guys,

I just took my newly purchased airboat out last night and what a blast. My only question is how much oil usually comes out of the engine on a normal run. My other boat has an oil water seperator and this boat just has a tube coming out of the crankcase with a small nozzle on the end of it. After about 20 minutes of riding I noticed oil covering one of the rudders and saw that it was coming out of the nozzle at a pretty good rate.

This seems like too much oil output, and I am new to aircraft engines so any help would be appreciated.

The engine is an 0-290 D lycoming.
 
I would do a compression check on your cylinders. If one (or more)cylinders are worn or a compression ring is bad the blowby caused will
pressurize the crankcase and pump oil out the tube( it's gonna go somewhere). Just an idea to check.

Good luck.
 
If you do a search you may find some info on the subject. I am not an aircraft motor guy but I know that a lot of peple here say that if you run the normal recommended amount of oil that it is too much for airboat application and that the extra just gets blown out? May help I dont know
 
How many quarts did it have in it at the beginning.
A lot of run outs will not hold what it says on the dip stick.
I used to have a one that called for 8 qts., but would blow two qts out, until it had about six left. Then it would run fine with great oil pressure until the hours were up up, and needed to be changed. Just keep an eye on your pressure and temperature. Most of these motors don't have the right dipstick in them anyway.
 
Schleppy,

Hope you will fill out your member profile on this site so we will know about where you are located. Seems like this might be a new experience for you - welcome aboard and good luck. It might be a good idea for you to take your boat to an aircraft A & P mechanic and get it checked out. That way, you'll have baseline engine data to work with into the future. He will likely do a compression leakdown test and that will reveal much abbout your engine. If you'll add your location, one of our members may just have a mechanic suggestion.
 
Do a leak down test and you will know the condition of your motor. Jeg's sells a leak down tester for $69. A leak down will tell you the condition of your pistons, bores, rings, valves and guides. 95% of the time that much blow bye is caused by to much oil in the motor or bad ring seal.
 
The motor was "just overhauled" before I purchased it. The motor has only 28 hours on it since it was gone thru and is still running the aero 100 oil for break-in. The cylinders were honed and the rings were replaced and one new cylinder was installed.
I was pretty happy to be driving the new rig and I got on the gas quite a bit. The gauge indicated 20psi oil pressure and I cant remember the temp, but it held steady.

What should the pressure and temp run on the 0-290d.
 
Was it overhauled by an A&P or in somebodies garage? Not dissing anyone just need to consider WHO did the overhaul.

I think I would go back to them and ask them to solve the problem. That crankcase pressure is coming from somewhere it isn't majic. Was the overhaul work guaranteed?

20 PSI oil pressure sounds a bit low to me unless your talking about at idle after warmed up.

I had a 125 years ago that did this same thing. Would use 4 quarts riding down the river and the same coming back. I had done something to it by trying to stay witht he big boats and making it cruise too fast. Lota years ago so details are gone, just remember the oil usage thing.

Scotty
 
I agree that 20psi does seem low---the guage my be wrong. A new engine can consume a good bit of oil breaking in, but I'd think the oil would come out the exhaust instead of the breather. Let us see a photo of how the breather tube is routed. How many qts of oil are you running? JJ says a new engine has to get at least 180 degrees to break in. I had one engine that took about 100 hrs before it quit using oil. I've heard the average is about 50 hrs. Good luck. I'm just an ignorant by stander, but some of the other guys on here will help you get it figured out. I'd go with their tip on the pressure check.
 
my 125 will run between 40-60 psi at start up and then drop to about 25 at idle. when I stomp on it , then it jump to between 35-40.
 
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