Oil Drain Tube

Capt Ron

My 5.0L MPI Mercruiser has an oil tube that can be lowered through the drain hole to drain oil from the engine without pumping through a dipstick. Has anyone connected an extractor to the end of this drain tube to pull the oil out without going through the dip stick??? If so, what size is the thread on the the end of the tube. I would love to made a connector to attached to this tube to drain the oil from the bottom of the pan rather than through the dip stick..?

Black_Diamond

I drain mine the same way. I think it is a 3/8" fitting.

frodo13056

Here's my setup: I use the moeller pump with the standard tube and attach clear flexible hose you can buy just about anywhere to the fitting shown in the pictures. Then I attach the brass fitting ( 5/16 barb to 1/4 inch MIP fitting) to the drain plug hose that is attached to the transom and I can completely empty an engine (warm) in about 5 minutes with no mess. I also punch a hole thru the oil filter (thanks for the suggestion Allswag!) to aid in minimizing that mess. I love the moeller pump - I have two so I can drain / refill both engines just before I pull the boat for the winter. The pump is truly multi-purpose: I use it to prime my AC in the spring, use it to change oil in the generator, use it to suck out the lower unit oil, use it to suck antifreeze into the AC unit, etc. I just went to Menards and bought sections of every size of the tygon tubing so that I can make adapter hoses, etc. for the various applications I use the pump for. One or two pumps on the moeller pump and it draws a vacuum for quite awhile so you don't have to keep pumping.

frodo13056

Second picture didn't post.......so here it is.

frenchship

Why would you need an extractor pump at the end of the drain pipe. Would the oil not drain properly with just the drain pipes ??

frodo13056

The Oil pan drains are supposed to be pulled through the transom plug and then drain the engines that way - but the boat needs to be obviously out of the water to do that. This technique allows me to run the engines while in the water to heat up the oil, then do the oil/filter change, then run the engines to coat all internal parts with fresh oil and verify oil level, then pull the boat out of the water. Just saves time so I don't have to change oil when the boat is out of the water and I don't have to climb In and out of the boat multiple times.

mvn

Yes, they are meant to gravity drain when routed through the transom drain, but guess what...... Rinker puts the depth gauge transducer right in front of the drain plug on the sport boats. There was no way I could get the drain hose through the drain hole. The fitting on mine is a 1/4" pipe thread. I made up a fitting to adapt my vacuum extractor and I was able to extract 5 liters of oil. I could never get that amount out using the extractor through the dipstick tube.

Mark

Capt Ron

Thanks Frodo -  your last photo was perfect in answering my question... Also agree that the hose drain is better than the dipstick method... I have never been able to get all the oil out through the dip stick... thanks to all who responded..
L-)