Boat Buzz

My 1948 M in my Deluxe Enlosed has a massive "leak" when running... took it out yesterday for it's maiden voyage (with me anyway) and we went about 10 miles round trip. In that amount of time, it discharged at least 6 quarts into the bilge. I had to keep stopping, checking, filling... we barely made it in on what oil I had onboard.

I looked, we got a mirror down there with a flashlight, couldnt see anything at all as far as where it's coming from. Does anybody with experience in these engines have any input at all that might save me from a huge diagnostic fee from the yard? Thank you very much in advance... obviously, she's laid up until I get a handle on this, and it's boating season

I attached an image taken overhead, just in case I'm wrong about the "M" name (I was told that's what it is... is that true or false?)

Yes i believe you have an m block. I dont know where your oi leak could be coming from exzactly but look at the gasket between engi e and trans, any rubber oil line hoses to a second aux oil cooler or gasket to prop shaft flange( sort of a trans rear main seal) , oil drain plug missing or loose on bottom of oil pan. Or fitting to oil pressue guage. Good luck finding the leak im sure you will find it soon before too many boating days go by. Heck there are people here near detroit that dint even have thier boat in the water yet.

You have an M engine (it should be stamped on the brass plate on the exhaust manifold) and it sounds like your oil leak is in a pressurized oil line. Run the engine at about 1000 to 1200 rpm at the dock and look all over for the leak. The oil pressure at those engine speeds should be about 20 to 30 psi and you should be able to find the leak.

It could be in a line that goes to or from the oil cooler or out of the engine block. The lines to and from the oil cooler are copper and they might have a crack or they might be leaking at the fittings. Or the oil cooler could be leaking. If it is not in those locations look all over the engine block, around the fuel pump and around the distributor. Also look at the outlet end of the transmission where the shaft runs through to the prop.

If none of this works have someone else drive the boat while you look for the leak. You'll find it.

Another thought. Did you over fill the crankcase with oil? If you pumped out six quarts and still had oil in the crankcase the excess oil may have blown out of the oil filler tube.

Good luck.

Frank

Oil level was at lower notch each time after adding 3 quarts, so there definitely wasn't too much oil in there. I did have someone else driving while two of us were back there looking and didn't see anything, which was frustrating... With that rate of loss, it shouldn't be so hard to find.

One thing that possibly may be related, probably not... The transmission slips out of forward into neutral at about 2000 rpm's. I was told that's an adjustment in the trans box, and I have looked all around that box for signs of a leak but nada.

Also, in case it makes a difference, the engine runs strong and steady aside from this oil thing, so hopefully it's just a tube or something.

One more thing... After shutting it down, and through that night, there was a noticeable gasoline smell in the cockpit, not too strong but noticeable. We had just filled up the tank, so I checked the water in the bilge at the stern area but it was just water, no gas. The oil had moved up to the cabin bilge pump area, next to the helm seat in the floor, and that water did smell somewhat gassy, very slight. Maybe it was just all the oil I was smelling, not gas, since all that oil seemed to move up into the cabin.

Check your fuel pump. Oil doesn't smell like gas and the diaphram in the fuel pump may be leaking.

It does sound like an oil line leak, but my concern is your lack of comfort dealing with this issue, particularly the gas smell. If you're not a gearhead, then you need to ask around and find a good marine mechanic who knows about these old engines. A gas smell is NOT something that should be ignored for even a minute. It is EXTREMELY dangerous. Secondarily, having that much oil pouring out of an engine indicates a catastrophic failure somewhere. Oil soaks into wood and weakens it over time. Good luck, sorry I am not closer.

Got to admit this one has me stumped????

Be sure to be careful, and let us know the problem when you locate it.

John in Va.

If you see no leak near the engine and the oil is mostly in the front of the bilge, I am thinking the oil line to a mechanical oil pressure gauge if you have one. There will be a thin copper tube that runs from the engine to the dash and if it breaks, it will leak oil at a decent clip when the engine is running.

The gas smell could be from the carb evaporating as the engine cooled down. I think mfine could be right about a line for your gauge.

Does anyone know where I can get a diagram of my engine? I believe it's a 95 hp M straight 6. I need to know where the oil drain plug is, and I'd like to see a schematic of the carb and where the oil pressure gauge sending unit is.

I searched in the archive but didn't find any detailed info.

An "M" is actually 130 HP. The oil pressure does not usually have a sending unit per se unless an electric gauge has been installed. There is usually a copper line that enters the block just under the coil and sends oil to the dashboard gauge. This is a mechanical gauge. If that line became disconnected from the back of the gauge or was split or broken at some point, oil would be pumping directly into the boat. The oil drain plug on the engine is on the side of the pan, way at the bottom on the right side. This is rarely used as it is so hard to get to. Most of us use a vacuum pump to suck old oil out of the dipstick hole.
You seem to have a whole lot of extra hoses and what appears to be an extra pump mounted near the generator. Is this some sort of closed cooling system?

Jim,

Yes, it's been converted to use a little tank which sits on top of the deck, in a corner,which gets filled with standard antifreeze / water mix.

I thought I saw something out there about 95 hp M engines do exist. No?

Just looked at my Mariners Museum packet... My confusion was based on the fact that a 95 hp engine was available for my boat, but it looks like the M is strictly 130 hp, like you said.

I do have the Hercules (K, M, etc.) manual in digital form. How do I post it here?
Doug

from the Hercules manuals

Thanks for posting that, Tom. Turns out it's *probably* a hole in the bottom of the trans casing.

I put 3 quarts into the engine fill tube, and 2 minutes later saw a puddle of oil creeping towards the back of the trans casing, towards the prop shaft. I then sucked all that out of the bilge with an oil pump container widget I have, and felt around under the engine and trans where I first started to see oil creeping towards the back. I found a corroded chunk of what *seems* to be metal (it had blue paint on it, but oddly it also had blue paint inside it when I broke it in half), about 2 inches long by an inch wide, fairly heavy, underneath the trans casing. In addition, there were lots of little bits of what looked like metal or iron flakes in that spot in the bilge. I then felt the underside of the trans case, and directly above were I found that chunk of metal there was an indentation or gouge out of the casing in what feels to be the same shape as the piece I found.

So, I took the cover off the top of trans and poured oil directly into the trans. Within a minute or so, that oil started to crawl through the bilge in same fashion as the first time. I can’t see under there and am only going by strong hunch, but it seems that the bottom of the trans casing is weak and an ever widening hole has developed.

The previous owner said he has a couple spares Paragon transmissions (he has a bunch of different spare parts), so now I guess I am looking for someone to replace the old one. Hopefully it can be done while the boat is in the water without pulling it.

Can the transmission be changed while the engine is in the boat and the boat is still in the water?

yes It can you just need something to pick the back of the motor up. when I work on the cruisers at the marina I attach a long chain to the engine and the other end the the marinas forklift and pick up the back of the engine and put a 4x4 block under the rear mounts that will pretty much make the engine sit level and the trans can be removed.