1990 Sunsport oil leak and rear plug question

[LFADAM]

First of all-someone at the marina where we keep our boat stole our rear drain plug...are they standard sizes for all inboards? If not, does anyone know what size this is? Im hoping my marina sells them or I can get it at Lowes. Im going out to the lake in less than an hour

Also, we seem to be leaking oil pretty badly now. I think it has been going for a while but very slowly (bilge water has always been somewhat oily), but now we are adding a quart every day or so. Pretty serious...what are some common locations/fixes to check on the PCM 351? Im hoping it's not anything too hard to fix

Thanks

[suprasam]

Yes I think the plugs are pretty standard, Walmart sells them and I would bet your local marina has them a dime a dozen.
Check your motor to see if you can find some leaks, the valve gaskets will sometimes leak and the gaskets can be changed fairly easy. Although a quart every day seems like a lot. Grab a flashlight, and do some searching, that much oil it should be to hard to trace where its leaking. Unless your burning that much oil a day...... Good luck!

[lively]

valve cover gaskets leak , oil pan , front main seal , distributor neck ... give a turn on all the bolts most all the gaskets will be cork and they have to be snugged from time to
time

[wotan2525]

A quart/day has to be the rear main seal or the drain plug has worked itself loose. Neither one is (probably) going to be fixed with the engine in the boat.

[Salty87]

please don't run the bilge pump like that. a small amount of oil can leave a large sheen.

in a pinch, the cork from a wine bottle will work for a rear plug.

[LFADAM]

Salty87, Luckily we dont have a bilge pump-just a ballast pump that we can use in an emergency (boat never stays in the water)

We got the plug, now just to find the oil leak. It definitely is a leak because you can see a good bit of oil in the bilge. Not burning a substantial amount. And the quart a day is a total guess. With the way that dipstick is on that engine it is totally impossible to see how much oil you really have. It twists/spins like 2 times when you pull it out, so the oil runs up the side. I just make sure there is some oil on the dipstick every time I go out. Does anyone else have this problem with this dipstick?

[Jetlink]

Dude, you're killing me... You have the 351 in that right? My dipstick does not twist or spin at all so there might be something going on. Truly when it comes to engines losing oil, there are one of two things, either a leak or you're burning it. If it is a leak, the best way to really find it is to pull the engine as it could be a host of many things, some that are not visible with the engine in the boat. Sounds like you are dealing with a leak though if it is in the bottom of the bilge. Other possible sources could include but are not limited to, where the oil dipstick tube enters the engine, the oild pressure sending unit (mine had a small leak), the drain plug or anything else somebody mentioned.