OMC 350 dipstick / drain plug combo

Went to change the oil in my OMC 350 and realized I have a strange dipstick/drainplug combo. The dipstick tube is attached to a banjo fitting on the bottom of the oil pan and the plug holds it all in place. Im guessing this style gives you an accurate reading no matter the angle of the engine. Anyway it also keeps you from identifying water in the oil - which there was plenty of. The oil on the dipstick looked clean, but I drained well over a cup of water and grey milkshakey oil. (another thread to come on that)
Im not home right now (currently deployed overseas - be home in 2 weeks) so no pictures. And I cant find an example online. Id like to change this out as its a total pain in the @ to remove/reinstall it. was thinking about a petcock style valve to ease draining also. Any info on these or replacements?

Re: OMC 350 dipstick / drain plug combo

HotKetchup said:

strange dipstick/drainplug combo.

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most (if not all) OMC engines over a 25 or 30 year span used that dipstick setup.
The top of the tube is threaded like a male garden hose connection to connect to a pump to pull the oil out
Can't say I've ever heard of anyone wanting to change it out, but if you want- compare parts from same year 350 in Mercruiser trim. Problem is, accessories and/or exhaust manifolds will often be in the way of any other dipstick tubes and drain fitting systems.

Re: OMC 350 dipstick / drain plug combo

Well since you'll soon be pulling that motor anyway, it'll be easier to deal with. Your dipstick is the least of your problems right now. Sorry to hear about the "sludge of death" in your oil pan.

Re: OMC 350 dipstick / drain plug combo

dockwrecker said:

Well since you'll soon be pulling that motor anyway, it'll be easier to deal with. Your dipstick is the least of your problems right now. Sorry to hear about the "sludge of death" in your oil pan.

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HEH Yeah Ive had that in the back of my mind as well. Its supposedly a fresh rebuild with only a couple hours on it prior to me getting it. I got it from a friend of a friend - a pretty trustworthy source. Ive only put a few hours on it total since Ive had it. I have beached it at a semi steep angle a time or two, maybe some water got backed up in there that way from boat wakes?? Sounds similar to another thread here about going in reverse and getting some water in there. Also had a bit of possible hydro-lock a couple times but after a few taps on the ignition it decided to start. Engine idles & runs like a top. I have some further troubleshooting to do before I jump into an engine pull. Just waiting to get home and the weather in Spokane to warm up a bit.

Re: OMC 350 dipstick / drain plug combo

Be aware that different years of OMCs used different fittings down there with different pitch threads on the pans. Whatever you do with your engine, keep that pan and all those fittings.

Re: OMC 350 dipstick / drain plug combo

Before you swap out that great setup, pull the exhaust hose going into your Y-pipe and see if the exhaust flappers are there. When the flappers had rotted out of my exhaust I got water into the engine when reversing on a few occasions. |That dipstick tube/drain setup makes it simple and effective to change the oil in you engine. I was able to draw out the water and put fresh oil in. The engine was fine it was just the missing flappers that caused the problem, once replaced it never happened again. I now check my flappers as a maintenace before spring launch. They are very easy to change

Re: OMC 350 dipstick / drain plug combo

That banjo fitting is the lowest point of the pan.
While the drain plug/dipstick may seem cumbersome, if you change it, how will you get the oil out of your engine effectively?

My '84 stringer had the same thing but the fitting was leaking very slowly, just enough to make a mess in the bilge. When I converted to Merc, I took it apart, put sealant on drain and tube threads, tightened 1 extra turn on both, all squeeky clean now.