Trying to change the oil on a friends boat with a mercruiser 228 and I cant get the oil to come up through the dip stick? I have tried 2 different hand pumps with the garden hose fitting and all I get coming through is air. I even tried taking the garden hose fitting off 1 of the pumps and hose clamping it directly to the dip stick tube and no dice. I'm either going to borrow or buy one now that has a hose I can feed all the way down the dipstick tube to get the oil out but how come my hand pumps dont work?

Make sure the oil is hot before you try sucking it out.

I would think either the dipstick tube doesn't go all the way to the bottom of the oil pan or dipstick tube has a crack/hole that prevents building up any vacuum within the tube. Either way, getting a skinny hose down the dipstick tube should take care of it. Like Craney said, oil needs to be hot.

If it's the same pump you use for other devices it might just be worn out.

Just playin. I'm assuming your getting good seal and as others mentioned oil is hot. Is it original pan and tube?

Good luck.

Some of the older engines had a dipstick tube/ pan that was basically from a car wherein the tube went through the side of the pan (or block in a sbc, 6cyl) and the dipstick went father down to measure oil level... problem with these is that when you try to pump them out without feeding a siphon tube down the dipstick tube to the bottom of the pan, you can only siphon out oil until the oil level is just below the top of the dipstick cut out... then it just pulls air

The new style ( what everyone associated with) has a dipstick tube that goes to the btm of the pan, and allows oil to be easily siphoned from just off the btm.

It's a mercruiser with a hose fitting near top of tube!

Heat the engine up and run the small plastic tubing down into the dipstick until you feel it hit pan bottom. The dipstick tube does not extend into the pan bottom much below full oil level so you are likely sucking air because of that. I would not use the dipstick tube itself.

I do this on my 502's and can get 7 quarts out every time. They hold about 7.5 qt to full line.

try this

Does the job

Built one years ago before they even sold I believe. Only way to go as far as I'm concerned. Easy, fast and "no" OOPS in the bilge resulting in a very bad day and lost time on the water.

Plus 1 on that advice!

Thanks guys. The oil has been changed. I'm assuming that the dip stick goes all the down to the bottom of the pan or it wouldn't have the threads on top of it. So theres either a leak somewhere in the
dip stick itself or maybe the tube is broken in the pan.