Smoke from Shaft and Cutlass Bearing !

[Privateer26]

26 Kenner Privateer in Morehead, KY, 1 cylinder 6 HP diesel engine is an English made Petter from late 60's.
-- 6/2012 problem still!!
Brass prop shaft has been smoking where coming threw the cutless bearing. Smoke smells like rubber. Could not run enough to get in and out of the dock as the prior summer progressed. Engine could run and run in idle with no issues. Assume spinning shaft friction heat making the cutless bearing clamp down on the shaft. We were sure the smoke was NOT coming from the engine. Hauled it out spring (2012) to paint the bottom and replaced the cutless bearing. Shaft is 1" brass and got a 1"X 4" bearing Duramax brass cutless bearing. REALLY hard to get the shaft driven into the bearing. Put boat back in the water and the #%*^$! thing is smoking after 30 seconds of being put in gear to leave the dock.
Same problem after spending money to haul it out and get new bearing, not to mention the labor time.
Any ideas on what to do? Maybe shaft is metric and we using the wrong size cutless bearing (shaft meauses 1")? Maybe we are assumming the wrong problem? 1 cylinder 6 HP diesel engine is an English made Petter from late 60's. Have no clue what to do and no boat yard anywhere near Morehead, KY. 606-356-6081 if you have any ideas. Would also love to know where to get more info on Petter engines/shafts, etc. Would love a call or response here.

[captain58sailin]

If you are having smoke, I would think it might be coming from your packing and or your packing gland. Do you have a steady drip of water from the front of your packing gland? If you have your packing gland is torqued too tight, that is a possible source of your friction = heat = smoke.

[Target9000]

Hey Privateer.

Thats a real bummer. Sounds like you may have undersized the cutless. Before you get too upset check all the small stuff though. Put the transmission in neutral and see if you can hand turn the shaft. Does it spin freely? It should.

Back off the stuffing box nuts a bit. Did you over tighten them by chance? I'm assuming you repacked on haul out with a cutless change. Make sure you check this too.

Finally, try and see if the engine is out of alignment. Take the shaft coupler off, but tie it off so it can't leave the boat, and adjust the angle by hand and try turning the shaft.

Just a few thoughts. GOOD LUCK!

[S/V Alchemy]

There's another packing gland fireworks thread nearby. I suggest you read it for inspiration and a methodology of diagnosis.

[Privateer26]

We have a "packless water seal" so no stuffing box involved. Pretty sure the prop does not spin freely. When we had it out of the water, it was tightish, not loose in the cutless bearing. It was pretty hard to turn by hand. Cannot find any data from Petter engines giving the size of the shaft. We assumed a 1", but it may be metric and be only something different. Any ideas on how to find this data on prop shafts? Has to be somewhere. This is an old engine and shaft: late '60's.

[bobconnie]

Don't know about any data on the motor, but Lowes sells simple calipers that will measure that shaft so ya will know what size it is!! sounds like ya mistook the size and got a tight one !! ya can some times fit the rubber by honeing it down a little so it turns easier by hand ! Ya must have been out of the water when ya did this job so ya will need to pull out again and measure the shaft and fix it !! just my 2 cents

[Astral Blue]

The packing gland would be the first thing I'd look at, especially if the smoke smells like rubber. You have given enough information to rule out the engine or transmission.

[Sailmonkey]

Did you "burp" the dripless seal?

[tosca36]

The propeller shaft should slide into the cutless bearing easily and smoothly. A too-tight fit means it's the wrong size. The smoke you see is the cutless bearing liner material burning -- it's often made of rubber. The smoke probably smells a bit like rubbery-plastic?

The full solution is what you've probably already guessed: haul it out and get the correct cutless bearing installed. Or just run it as it is. The bearing will wear fast, you might use a bit more fuel but your prop sharft should survive it -- providing it's properly aligned.

[osirissail]

Originally Posted by Sailmonkey

Did you "burp" the dripless seal?

+1 on that. You hauled the boat out of the water removed the shaft and cutlass bearing and installed a new one. Then put the boat back into the water . . .

Unless you opened a gap by compressing the dripless seal rubber boot and let sea water gush out into the boat bilge for a second or two - you have trapped air in the shaft log from the dripless seal all the way back to the exit and cutlass bearing. You have to let the trapped air out of the shaft log so that lubricating water can enter the cutlass bearing and shaft log.

[psneeld]

if you have smoke from a cutlass bearing making it through your packing gland (dripless or otherwise) you have BIG problems...

What kind of dripless packing???...if PSS, sounds like you are burning up the "O" rings...which could mean the stainless seal ring is spinning...and it shouldn't!!!

[Privateer26]

Thank you to all for suggestions/ideas. Here are answers to your questions:
1. Yes, we burped the packless water seal but will do again.
2. We think we can get to the shaft from inside to measure with a micrometer to make sure of the size.
3. Yes, smells rubbery. Would run it anyway with a tight fit, but it is so tight, it pulls the engine down and it quit (with this new bearing and had slowed and smoked with the old bearing). Have tried squirting lithium (2 summers ago when same problem kept rearing it's head) into the rubber groves of the bearing and it helps to get a small distance (to the dock at least) . This task has to be done underwater. Not fun.
4. A call we got mentioned possible alignment issues. Engine has never been moved and when putting the shaft back in, coupler and shaft were pretty much together. Maybe a shift but mounted on hard rubber pads.
Oh, we forgot to put the bearing in the freezer first before putting it in the hull, and it was VERY hard to get in so you would think it was the proper size (large enough to be very tight). On this pattern of thinking, you would assume the hole for the shaft would be generous as well, but it seems to be too small...
Would welcome any other ideas/suggestions.

[osirissail]

Originally Posted by Privateer26

. . . 3. Yes, smells rubbery. Would run it anyway with a tight fit, but it is so tight, it pulls the engine down and it quit (with this new bearing and had slowed and smoked with the old bearing). Have tried squirting lithium (2 summers ago when same problem kept rearing it's head) into the rubber groves of the bearing and it helps to get a small distance (to the dock at least) . This task has to be done underwater. Not fun.
4. A call we got mentioned possible alignment issues. Engine has never been moved and when putting the shaft back in, coupler and shaft were pretty much together. Maybe a shift but mounted on hard rubber pads.
Oh, we forgot to put the bearing in the freezer first before putting it in the hull, and it was VERY hard to get in so you would think it was the proper size (large enough to be very tight). On this pattern of thinking, you would assume the hole for the shaft would be generous as well, but it seems to be too small...
Would welcome any other ideas/suggestions.

Based on the bolded underlined text above - either of two things are wrong.

First you have the wrong size cutlass bearing which is highly probable. With a proper sized cutlass you should be able to turn the propeller by hand.

Second, the engine has shifted either because of an engine mount failure or some other reason to put the engine out of alignment. The transmission normally has a two part "flange" - one part attached to the transmission and the other half attached to the propeller shaft. The two parts are slid together and held by several bolts and nuts. As you slide the two parts of the flange together you measure with a "feeler guage" the gap between the two parts at at least 4 different quadrants of the coupling. The idea is to have the same "space or gap" all around the two parts of the coupling. This confirms that the resting position of the propeller shaft/coupling aligns with the engine/transmission/coupling half.

If the two parts of the coupling are not parallel or are tilted to each other then the engine/transmission will exert an off center force on the propeller shaft and rub against the cutlass bearing. With older engines with old engine mounts or broken engine mounts this is not uncommon.

[atoll]

Originally Posted by osirissail

Based on the bolded underlined text above - either of two things are wrong.

First you have the wrong size cutlass bearing which is highly probable. With a proper sized cutlass you should be able to turn the propeller by hand.

Second, the engine has shifted either because of an engine mount failure or some other reason to put the engine out of alignment. The transmission normally has a two part "flange" - one part attached to the transmission and the other half attached to the propeller shaft. The two parts are slid together and held by several bolts and nuts. As you slide the two parts of the flange together you measure with a "feeler guage" the gap between the two parts at at least 4 different quadrants of the coupling. The idea is to have the same "space or gap" all around the two parts of the coupling. This confirms that the resting position of the propeller shaft/coupling aligns with the engine/transmission/coupling half.

If the two parts of the coupling are not parallel or are tilted to each other then the engine/transmission will exert an off center force on the propeller shaft and rub against the cutlass bearing. With older engines with old engine mounts or broken engine mounts this is not uncommon.

good advice here,it does sound very much like you have a 1" shaft(25.4 mm)

that has had a metric cutlass bearing fitted 25mm!

[Privateer26]

We did order and install a 1" X 4" cutless bearing. If the shaft is metric, 25.4mm and no 1 inch, then the opening in the bearing should be too large, not too tight. Right?