Lehman 120--oil change? How to?

I want to change the oil on my 1982 Lehman 120. Boat has a oill change kit with a sucki9on hose with a 3/4 hose barb. Where do I connect it to. The dipstick tube will not fit.??? Help. Thanks..

There are two fairly easy ways to get the oil out of a marine engine, since you can't just open the drain fitting and drain it to an oil pan like you can with a vehicle.

Marine oil change kits are based on a small pump, either manual or electric driven that suck the oil out from the dipstick tube. It has a tube small enough to fit down the tube where it can suck the oil out.

The other way is with a permanently installed pump like the Reverso. The pump is permanently connected to the engine oil pan's drain fitting. This has to be installed after all the oil is removed the other way. But once installed you just have to set the valves properly, put the discharge hose in an empty oil container and turn it on. These systems have two or more suction fittings so you can also hook them up to a twin engine, a genset or ???

Actually your kit could be either. Buy with a 3/4 hose barb it sounds more like the permanent plumbed in type. Does it have a brand name on it?

David

I have Lehman SP225s in my boat. They each have a petcock on the oil pan drain with a hose hooked to the petcock. I have a Jabsco 12 volt oil change pump that originally came mounted on a 3 gallon bucket. I took the pump off the bucket and hook it to the hose from the oil pan. It takes about 3 minutes to pump out the 22 quarts in each engine into a 5 gallon jerry can. Also on the 120 you need to change the oil in the injector pump. Recommended to change the injector oil every 50 hours at first until you know how diluted the oil gets.

Your description of the oil change kit confuses me. Does it look like it has been used or is it something the P.O. bought but did not install? 3/4 inch barbed fitting sounds like it would replace the oil drain plug. Do you know what a "banjo" fitting is ? This is the most common type of drain plug replacement.

It sounds like your fitting will be permanently installed, a task you can not accomplish while there is oil in the engine. You will have to drain it out either through the dipstick or figure out a way to catch the oil when the drain plug is removed.

The drain plug is on the starboard side near the rear of the engine. Unless your piston rings are showing some wear there will be no pressure inside the oil pan. You do not need to valve the drain hose off but it is probably a good idea to plug it with a bolt of other plug, also keep it away from any moving parts or engine parts hot enough to melt the hose.

However you choose to drain the engine, it is best to run it for a few minutes to warm the oil and allow it to flow better. If you choose to somehow catch the oil after removing the drain plug, remember, there is a lot of oil! Like around 5 gallons. I suppose you could remove the drain plug and working quickly install the barbed fitting before too much oil drains into the bilge or whatever pan you have fashioned under the engine. Lots of things could go wrong with this approach though, it could really get messy. Personally I would rather work with an engine which had been drained, even a partial drain through the dipstick could make the job less messy.

Good Luck,

pete

American Diesel sells on oil change hose kit. It is a 2' long hose that replaces drain plug in oil pan. You can then use a manual or elec pump to remove oil.
Sounds like PO modified it?

Manual - https://www.westmarine.com/buy/west-marine--manual-oil-changer-2-9-quart--11097714?recordNum=3
Elec - https://www.westmarine.com/buy/west...-12v-oil-changer-bucket--14557425?recordNum=5

Or you can really spluge and get the Reverso, The manual is slow but workable and will drain transmission or engine via dipstick tube.

A Lehman 120 holds approximately 12 quarts of oil or 3 gallons.

As old as these engines are, with multiple previous owners, most have had some sort of oil drain fitting with a length of hose installed to replace the drain plug.

And to add to Commodave's injection oil pump change recommendation. Be real careful tightning the drain plugs on the injection pump. They screw into the aluminum pump body and can strip the threads of the body easily.

The fill plug at the top is also a PITA. It has a large slot for a flat screwdriver. The problem is that the slot is bigger than any flat screwdriver available so the screwdriver slips out of the slot eventually buggering it up so vicegrips becomes necessary to remove the plug.

That plug is a 5/8" X 18 thread which is a common oil drain plug size available from Amazon or any auto part store. I reduce the diameter of the plugs shoulder a little in order to clear the fitting next to the plugs hole on the top of the injection pump.

syjos said:

A Lehman 120 holds approximately 12 quarts of oil or 3 gallons.

As old as these engines are, with multiple previous owners, most have had some sort of oil drain fitting with a length of hose installed to replace the drain plug.

And to add to Commodave's injection oil pump change recommendation. Be real careful tightning the drain plugs on the injection pump. They screw into the aluminum pump body and can strip the threads of the body easily.

The fill plug at the top is also a PITA. It has a large slot for a flat screwdriver. The problem is that the slot is bigger than any flat screwdriver available so the screwdriver slips out of the slot eventually buggering it up so vicegrips becomes necessary to remove the plug.

That plug is a 5/8" X 18 thread which is a common oil drain plug size available from Amazon or any auto part store. I reduce the diameter of the plugs shoulder a little in order to clear the fitting next to the plugs hole on the top of the injection pump.

Click to expand...

Nice mod but a big slotted screwdriver works fine for me.

SoWhat said:

American Diesel sells on oil change hose kit. It is a 2' long hose that replaces drain plug in oil pan. You can then use a manual or elec pump to remove oil.
Sounds like PO modified it?

Manual - https://www.westmarine.com/buy/west-marine--manual-oil-changer-2-9-quart--11097714?recordNum=3
Elec - https://www.westmarine.com/buy/west...-12v-oil-changer-bucket--14557425?recordNum=5

Or you can really spluge and get the Reverso, The manual is slow but workable and will drain transmission or engine via dipstick tube.

Click to expand...

I do have a Oil Change Kit like the $209 West Marine kit but it is a 5 gallon home made one.