Prop Won't Go into Gear

[fsuhansell]

Hi all,
I took my boat out yesterday only to get 100 yards from the dock and find myself not able to get the prop to engage in forward or reverse. Since then I've been towed back to my slip and am currently trying to id the problem. The first thing I checked was if the lever on the gear box was activating when I moved the shifter on the pedestal and unfortunately it was. Next I tried to spin the shaft by hand to check if it was ceased by it spun fine in neutral. Oddly to me it would spin only one direction in forward and only the opposite direction in reverse. I would have thought it wouldn't be able to spin either way once in gear. Since there was water in my gearbox when I first got the boat I decided to check and again the oil in the gearbox is milky white indicating water in the oil. Also I noticed the oil level was higher than the mark on the dipstick which I contributed to the additional water now in there. I plan to fix this problem anyway, but I'm wondering if it could be linked to the prop not engaging problem. Once I change the gearbox oil ill start the engine and do some more trouble shooting. I have a yanmar 2GM20 diesel with a KM2P gearbox. I'm always extremely appreciative of any help and advice as this is my first boat and my knowledge and experience is very limited. If you have any ideas I would love hear them.
Thanks,
Mike

[AnchorageGuy]

First, you need to figure out where the water is coming from, probably from the transmission cooler if you have one. Next you will need to pull the transmission and have it sent to the shop for repairs. Chuck

[perchance]

From your description it sounds like you have a clutch dog shift mechanism to go from forward to reverse. The shift lever will still work if the cable is broken. You need to shift it at the transmission and see if it goes into gear. If if it doesn't it's time to get the manual out and dig deeper.

[DeepFrz]

Does the transmission have an oil cooler? If it does that is likely where the water comes from. If it doesn't then maybe you didn't get all the oil and water out of the transmission the first time and may need a couple more oil changes to completely get all the water out.

Have you tried shifting from the gear box when the motor is running?

[Domenic]

Originally Posted by fsuhansell

Hi all,
I took my boat out yesterday only to get 100 yards from the dock and find myself not able to get the prop to engage in forward or reverse. Since then I've been towed back to my slip and am currently trying to id the problem. The first thing I checked was if the lever on the gear box was activating when I moved the shifter on the pedestal and unfortunately it was. Next I tried to spin the shaft by hand to check if it was ceased by it spun fine in neutral. Oddly to me it would spin only one direction in forward and only the opposite direction in reverse. I would have thought it wouldn't be able to spin either way once in gear. Since there was water in my gearbox when I first got the boat I decided to check and again the oil in the gearbox is milky white indicating water in the oil. Also I noticed the oil level was higher than the mark on the dipstick which I contributed to the additional water now in there. I plan to fix this problem anyway, but I'm wondering if it could be linked to the prop not engaging problem. Once I change the gearbox oil ill start the engine and do some more trouble shooting. I have a yanmar 2GM20 diesel with a KM2P gearbox. I'm always extremely appreciative of any help and advice as this is my first boat and my knowledge and experience is very limited. If you have any ideas I would love hear them.
Thanks,
Mike

If your shifter/gear box uses a push-pull cable...that may be your problem. A new cable will last between five years to 5 days. They jam up inside. The is no way to fix them. It is better to build a gear, and chain system like on a bike. Easy to oil, always works.

[Domenic]

As to the water in the gear box. Does you engine oil also oil the gear box? Do you open the outside water flow to the engine before you start the engine?
If your answer is yes to both of these questions, that might be your problem.

If outside water flow is open when you hit the starter...the water pump starts pumping water. If the engine does not start at first, water will back up into the manifold, into the pistons, and right into the engine, oil pan, and gear box.
Always start the engine before opening the outside water flow.

[S/V Antares]

That trans is a mechanical cone type (no dogs) that has no provision for a cooler as it is splash lubricated. When in gear it will turn by hand in one direction. If you put it in gear in another direction it will turn the oposite way. That is to say, it does not lock up both ways when in gear.

So... it sounds like it is going into gear. The water, if this is what it is and not just airated oil, is troubling.

Has the gear been subjected to high water in the boat? It would have to get up to the rear seal or higher to the breather on the top of the gear.

The issue appears to be in the linkage or did the prop fall off? (Dont laugh! it happen more than you think)

[Hartleycruiser]

I have a 3QM30 with a kh19 gearbox and it will rotate only one way when put into gear.That is to say, it does not lock up both ways when in gear.

I have also had a problem with the oil not being at the corect level/viscosity causing the clutches to slip.I would drain and change the oil ,hopefully this will solve the problem.
Have you found how the water got in the gearbox.

[FSMike]

Originally Posted by Domenic

Do you open the outside water flow to the engine before you start the engine?

Always start the engine before opening the outside water flow.

People do things in different ways, but I gotta admit I've never done that in my entire life.

[Vyndance]

Originally Posted by Domenic

As to the water in the gear box. Does you engine oil also oil the gear box? Do you open the outside water flow to the engine before you start the engine?
If your answer is yes to both of these questions, that might be your problem.

If outside water flow is open when you hit the starter...the water pump starts pumping water. If the engine does not start at first, water will back up into the manifold, into the pistons, and right into the engine, oil pan, and gear box.
Always start the engine before opening the outside water flow.

Oh I have got to hear how this works. Please explain.

To the OP, If the trans is not fresh water cooled with a heat exchanger, there is no way except for wash down water to get into it. If it does have a heat exchanger it needs to be replaced.

[osirissail]

To the OP, depending upon your propeller mounting situation, you may indeed have sheared a pin or sheared the key or the propeller may not be still on the shaft.
- - If the engine in gear (forward or reverse) accelerates rapidly with throttle movement and without any motion of the boat, then the propeller has a problem.
- - But in any case from your description you did "power out" of the slip and then the problem started. It is not uncommon when you shift and apply power to stop the boat motion that the propeller will spin off the shaft. It happened once to me.
- - If the shift lever will not physically move to cause the transmission to fully engage, then maybe a shifter or shift cable problem.
- - You should be able to disconnect the shift cable from the shift mechanism on the transmission and move the mechanism by hand. If the shift cable has a problem in its attachments to the transmission or the shift lever up in the cockpit you may not be "fully" engaging the gears.
- - With the transmission shift mechanism manually moved to the full forward or reverse position by hand, the propeller should try to move the boat. If not then the transmission has a serious problem. That is your "proof positive" that the transmission has an internal fault.
- - As mentioned by others that if you do not have a transmission cooler there is no logical way water can get into the transmission unless you submerge it.
- - Once the engine/transmission has fully cooled down the transmission fluid should be its normal color and not "milky white." It may be dark or somewhat "brown" if the insides of the transmission are grinding away. And there are slip rings and other mechanisms inside the transmission that need to engage before the unit will output to the propeller. If these are "shot/worn" then you will get what you described.
- - These days, a transmission rebuild is most likely a transmission exchange, yours for a previously rebuilt unit.
- - So unless you have a simple mechanical problem with the shifter, shift cable, or propeller you are looking at a transmission rebuild or exchange.

[Domenic]

Originally Posted by Vyndance II

[/B]
Oh I have got to hear how this works. Please explain.

To the OP, If the trans is not fresh water cooled with a heat exchanger, there is no way except for wash down water to get into it. If it does have a heat exchanger it needs to be replaced.

Many inboard marine engines oil the gear box, and engine from the same sorce. If this is the case with your engine, and you have water in the gearbox oil, You will have water in your engine. There are only four ways water can get into the engine oil
1) You poured water through the oil fill tube.
2) Cracked block.
3) Head gasket.
4) Outside water intake valve is open, and you crank the engine over, and it does not start. The water pump is pumping water through the engine, and out the exhaust house. If the engine is not running, but turning over it will have back pressure, and suck the water into the manifold, into the lifters, and into the engine. You will have water in your pistons, and oil pan.
If you think number 4 is your problem, remove a spark plug, and see if you have water on top of the piston. If you do, hand crank each piston to the top, clear it of water. Put about three table spoons of MMO into each cylinder, and hand crank the engine to prevent rust in the cylinders.
I don’t think anyone would do number 1. Number two you have a big problem. Number 3 you can fix yourself. Number 4 is a simple fix.
Number 4 applies to engines that exit water via the exhaust, and oil is shared between engine, and gear box.

[Domenic]

SIDE NOTE TO MY POST:

If your engine was NOT over heated, The chance that you have a cracked block would be zero.

[Vyndance]

I just can't think of anything to say that would not get me banned.

[nv5l]

Originally Posted by Vyndance II

I just can't think of anything to say that would not get me banned.

Say about what?