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HELP! Onan Genset Model 2.5LK spec N


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  #1  
Old 01-01-2010, 03:51:04 PM
PowerGuy PowerGuy is offline
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Default HELP! Onan Genset Model 2.5LK spec N

First time. Thanks for letting me join.

I have recently purchased a 1984 Bucket Truck, with an Onan Genset Generator mounted in the back that controls the bucket power and hydraulics. I have searched for the manual for hours online with no luck.
The Generator cranks but will not start. I have basic knowledge of small engine troubleshooting, but I have never dealt with this type.
It is a gas generator feeding off of the truck gas tank. What I thought was an air filter was actually a oil container. Is this a 2 cycle engine? Mixing the oil with the truck gas. It seems that the plug is oil fouled, even when switched to another plug.

Any help would be greatly appretiated.

Thanks again.
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Old 01-01-2010, 08:29:18 PM
Kimbra Dean Kimbra Dean is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

Engine is 4-cycle. Suspect you have an oil bath air filter.
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Old 01-01-2010, 09:56:47 PM
bobbyz72 bobbyz72 is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

You need 4 things for the engine to run. Air, fuel, Spark, and exhaust. Find out with one your missing. Has long has it been since it last ran, the oil in the cylinder could be your whole problem. Clean up the oil in there and try again.
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Old 01-01-2010, 10:30:27 PM
mrmegoo mrmegoo is offline
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Talking Re: HELP! Onan Genset Model 2.5LK spec N

Compression. Another important element to the run equation.
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Old 01-02-2010, 12:09:47 PM
PowerGuy PowerGuy is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

I was told it ran, and had been used two months before I purchased. I purchased it online and sent a friend to pick it up, so I wasn't there to ask any questions on starting or running.
Not sure why it is getting oil in the cylinder. I have taken the plug out and cranked engine to dry out the oil, only to put another plug in with the same results.
I am going to test the compression and make sure the gas line is not clogged, Soon.
It is 19 degrees out right now.

Thanks for the help.
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Old 01-02-2010, 01:46:09 PM
Wayne Hansen Wayne Hansen is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

If you are getting oil in the cylinder you might like to check the breather valve.
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Old 01-02-2010, 02:33:47 PM
Ben Clarke Ben Clarke is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

My 2.5 LK has a metal air cleaner that is supposed to be coated with motor oil. If yours is the same is it possible that some one got carried away with the oil thing and super soaked the filter?
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Old 01-03-2010, 01:12:27 AM
Max Thompson Max Thompson is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

Power Guy:
I have a PDF of the Onan LK “parts manual”. Covers through spec. N, if you pm me an e-mail address that can handle the down load, I will send it your way. It does not show the oil bath air filter that I have on mine & you may have on yours but may help.
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Old 01-03-2010, 01:55:05 AM
shopman shopman is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

PM me a valid email address that accepts large attachments and I'll send you a service manual.

I just finished rebuilding an LK that burned oil like a sieve. I removed the head and you could watch it pump oil past the rings as the crank was rotated. My problem was a cracked piston which caused the rings to bind. New piston, rings, exhaust valve and it runs like a top.

Check all the obvious things first like the crankcase breather as suggested above. A plugged breather will cause it to force oil past the rings. Check for spark since it sounds like you don't have any. Even with my unit pumping large amounts of oil past the rings it would still start. Check the point gap and the condition of the points themselves. If oil has made its way into the point box it could be on the contacts which will insulate them and prevent them from working. You could also pull the head and see what the carbon situation is. This will also allow you to see what kind of shape the valves and piston are in.

Lots of stuff to check and an orderly approach is best. See if you have spark and if so move on to fuel. If fuel is making its way into the cylinder then it's time to look at compression.

Steve
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Old 01-01-2011, 10:37:00 AM
SirReal SirReal is offline
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Default Re: HELP! Onan Genset Model 2.5LK spec N

I have the exact same (as described) bucket truck. My Onan genset 2.5 lk is a little under the weather. I need some help with the parts. Especially, the electrical controls under the hood. The square plastic wire assembly component (unsure what to call it) is gone and I need a new one.

Can you email me the manual? Use email address tonight(at)1016pm.com

Thanks!
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