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#1
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Removing lower unit from 40 hp Johnson outboard - Help?
Hi,
I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#2
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Removing lower unit from 40 hp Johnson outboard - Help?
Disconnect the shift rod from under the carb. There are two versions. One
has a bolt that has to be removed. The other has a pin that (once you remove the shift cable and remove the pin located behind the shift arm) the entire assembly will slide to port and allow the shift rod to be released. Please remember to not turn the shift rod. It is adjusted to the right height and if you turn it, you will get the adjustment out of wack and end up stripping the clutch dog in the lower unit. -- Tony my boats and autos - http://t.thomas.home.mchsi.com "Brian Silver" wrote in message om... Hi, I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#3
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Removing lower unit from 40 hp Johnson outboard - Help?
Careful the prop is supposed to spin freely in one direction when the
selector is in forward. it protects the prop if you hit something. Paul (Brian Silver) wrote in message . com... Hi, I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#4
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Removing lower unit from 40 hp Johnson outboard - Help?
Can you explain *exactly* how this "protection" works? -W "Paul Dougherty" wrote in message om... Careful the prop is supposed to spin freely in one direction when the selector is in forward. it protects the prop if you hit something. Paul (Brian Silver) wrote in message . com... Hi, I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#5
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Removing lower unit from 40 hp Johnson outboard - Help?
Sure, on my outboard if it is in forward, with the motor not running,
the prop will spin clockwise but not counter-clockwise. There is a one way clutch in the gear box that causes this to happen. Now when the motor is running in forward gear the gearbox will turn the propeller to move the boat forward. But, if the prop hits something it will stop turning but the motor and the gearbox are protected because the one way clutch will allow them to spin freely. My outboard is a 1985 25 hp Mariner so this might be unique to them. I do not know. It also does not have a shear pin because the clutch will allow everything to turn free. I can tell you first hand that this work well because I had a rock stuck between the prop blade and the cavitation plate the motor would rev up and the boat would not go anywhere until I got that rock out. Paul "Clams Canino" wrote in message news:HaDdb.613735$o%2.286517@sccrnsc02... Can you explain *exactly* how this "protection" works? -W "Paul Dougherty" wrote in message om... Careful the prop is supposed to spin freely in one direction when the selector is in forward. it protects the prop if you hit something. Paul (Brian Silver) wrote in message . com... Hi, I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#6
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Removing lower unit from 40 hp Johnson outboard - Help?
Thank you.
Now let me explain the way I understand it: grin No, it's not unique to your motor - most all of them do that. Think of it just like a ratchet - it'll spin - but under drive it's an absolute connect. If the ratchet pawls slipped under high load - your ratchet needs to back to Sears. Now if the prop is somehow immobilazed AS you put it into gear - then it may not engage - accompanied by a very loud grinding noise as the thing tries to drop in but kinda "can't". What really happens is the the one way "pawl action" of the prop allows the propeller "in all cases" to spin forward faster than the motor is turning. That menas when the motor is stopped you can turn it clockwise and it will click click click. I assure you that if for some reason you were cruisong along with the prop at 2000 rpm and "the hand of god" reached down with the ability to turn it at 2004 rpm - it would still go click click click. In other words the prop can always turn ahead. What this action does is allows the prop to "free wheel" a bit when the boat is moving along at WOT and you decide to chop the throttle. Try it and listen, you'll hear the prop clicking away till the boat slows down. This protects the drivline from "trying to turn the engine" - something it was not meant to do. I assure you, that in a case where the engine is driving the prop (assuming all is tight and correct)that the connection from the engine to the prop is pretty much absolute and non-negotiable. What happens when something tries to stop a prop under power is: A) the prop gets damaged. B) the driveline gets damaged. OR C) The prop spins on it's rubber hub. Trust me that I've seen props (aluminum and stainless steel) get torn up at every RPM and boat speed imaginable. NOw, in your case, I'd bet money that your prop has a rubber hub separating the splined part that goes over the propshft, from the prop itself. This is visible only from the rear of the prop as a general rule. So, what happened is your prop "spun on the hub" when it was engaged with the rock, and later with the rock removed it functioned normally again. On a bigger motor, the prop may well need to get "re-hubbed" after such an episode. In your case you got lucky and the low torque of your 25hp motor was not sufficiant to exploit the (somewhat)weakened condition of your pressed in prop to hub rubber bushing. The ratchet was not in play saving your prop. If it was, you would have heard a hell of a grinding noise - and not reved the motor at all out of fear. -W "Paul Dougherty" wrote in message om... Sure, on my outboard if it is in forward, with the motor not running, the prop will spin clockwise but not counter-clockwise. There is a one way clutch in the gear box that causes this to happen. Now when the motor is running in forward gear the gearbox will turn the propeller to move the boat forward. But, if the prop hits something it will stop turning but the motor and the gearbox are protected because the one way clutch will allow them to spin freely. My outboard is a 1985 25 hp Mariner so this might be unique to them. I do not know. It also does not have a shear pin because the clutch will allow everything to turn free. I can tell you first hand that this work well because I had a rock stuck between the prop blade and the cavitation plate the motor would rev up and the boat would not go anywhere until I got that rock out. Paul "Clams Canino" wrote in message news:HaDdb.613735$o%2.286517@sccrnsc02... Can you explain *exactly* how this "protection" works? -W "Paul Dougherty" wrote in message om... Careful the prop is supposed to spin freely in one direction when the selector is in forward. it protects the prop if you hit something. Paul (Brian Silver) wrote in message . com... Hi, I am new to boating and screwed up my lower unit. I think I stripped the gears because at one position the prop will rotate freely while in gear (forward). I removed the 5 bolts below the anticavitation plate and the lower unit has dropped an inch but is being held by the shifting linkage rod. Am I looking for trouble or can I remove the lower unit easily. I think the shifting rod can be freed up from under the carburator(s) Would I then slide the whole rod out? Would I mess up the shifting setup? I have all winter to work on this and so far it has been interesting, Thanks for the responses in advance, Brian Silver, Little Long Lake, Ontario, Canada. |
#7
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Removing lower unit from 40 hp Johnson outboard - Help?
Raise your hand if you smelled this one coming a mile away.
-W PS: No Paul, I didn't set you up for a beating. (and sorry) I just wanted to make sure a couple thousand readers out here understood their propeller is *not* protected by anything in the lower unit. Those props are out there on their own flapping in the breeze folks. Nothing in the lower unit is gonna help save them if they strike something. I just needed to make that very clear. "Clams Canino" wrote in message news:ISNdb.626408$Ho3.120279@sccrnsc03... Thank you. Now let me explain the way I understand it: grin snip |
#8
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Removing lower unit from 40 hp Johnson outboard - Help?
Let me hedge a bet though by way of correcting myself a little and coming
closer to your corner. IF you can grab the prop and pull it rearward about 1/4 inch (shaft and all), then there might be some kind of "spring loaded slop" built in to allow the shaft and it's gear to disengage from the drive in the event of a strike from the front of the prop toward the rear. If such a thing is/was intended - I've never seen it work in practice. -W "Clams Canino" wrote in message news:ISNdb.626408 The ratchet was not in play saving your prop. If it was, you would have heard a hell of a grinding noise - and not reved the motor at all out of fear. -W |
#9
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Removing lower unit from 40 hp Johnson outboard - Help?
"Tony Thomas" wrote in message news:KVqdb.608756$uu5.99381@sccrnsc04...
Disconnect the shift rod from under the carb. There are two versions. One has a bolt that has to be removed. The other has a pin that (once you remove the shift cable and remove the pin located behind the shift arm) the entire assembly will slide to port and allow the shift rod to be released. Please remember to not turn the shift rod. It is adjusted to the right height and if you turn it, you will get the adjustment out of wack and end up stripping the clutch dog in the lower unit. -- Tony my boats and autos - http://t.thomas.home.mchsi.com Thanks for the info Tony, this is a great resource by the way, maybe someday I will be able to contribute. Brian Silver, Little Long Lake, Ontario, Canada. |
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