Couple weeks back, we were traveling down the river up on plane and all of a sudden lost power to the prop. Motor was revving just know power. Thought it was a shifter issue or blown prop hub but after getting it out of the water and investigating, it was neither. Prop shaft is getting no power but the motor runs fine and not making any noises. No grinding clanking or other abnormal noises.
I know its not the shift cable because it seems to be shifting fine. In F you can turn prop one way by hand, N both and R neither. I had someone suggest maybe a clutch in the lower unit but I’m not sure how to check that. Also not a blown prop hub because the prop shaft is not turning when the motor is started without the prop on.
Over the break I dropped the lower unit to take a look. Drive shaft looks fine but when turned the prop shaft does not move and there is some resistance on the drive shaft. Any suggestions at this point? I may just have to take the lower unit into a marine mechanic and have them diagnose the issue since I’m not sure I am comfortable pulling into the lower unit anymore than the water pump.
If I had blown the lower unit, I would have thought it would have made a lot of noise so I’m hoping it is just a wear sleeve or bearing that has worn out.
The motor is a 1997 90 hp Mercury 3 cyl. 2 stroke oil injected. Any suggestions on which mechanic to take the lower unit to around Charleston and how much it might cost just to diagnose the issue? If major repairs are needed, they will have to wait until Jan. when I start my new job.
still sounds like a prop hub to me
crank the motor up on the hose and shift it in and out of gear, it will probably work normally
when you put a load on the prop, thats when the hub will slip
Chris I started the motor a few weeks ago in the driveway with the prop off. When I put it in gear (forward and reverse) there was no movement of the prop shaft. If it was a blown prop hub, the prop shaft should still turn, correct?
Yah it is shifting. I can see the shift rod rotate when it is flipped into gear and in F you can turn prop one way by hand, N both ways and R neither. so shifting seems to be fine to me. Thanks for the ideas.
im a bit confused
you can shift it into gear, and it locks, with the motor turned off
when the motor is running, on the hose in the yard, and you shift, nothing happens? no grinding, no clicking, and no prop spinning?
the waterpump will cause resistance on the drive shaft when you turn by hand.
without seeing it, i dont know what else to tell you
Yah Im confused by it too. shifts fine but no power to prop shaft, no grinding , no noises. I might be bringing it into you when i start my new job and have some money. Thanks for the help.
Drained the lower unit oil today and the magnet had 3 chunks and some shavings of metal on it so it looks like i busted a gear, probably at least the pinion gear. Also the oil was pitch black. I think that means there was exhaust leaking into the lower unit. That oil was changed less then a year ago and the boat hasn’t been used much this year. I think I will start looking at the SEI lower units. I might pull into mine next weekend but it probably won’t be cost effective to try to repair when I can buy a new one with 3 year warranty for around $1000. What would you guys do in this situation? The boat is going to have to sit for the winter until I can save up the money to do anything to it, so I have a few months to think about it.
The chunks of metal are definitely a bad sign. Don’t think exhaust was leaking in. Black oil just means its past due for a change. If exhaust was getting in so would water and the oil would look milky.
I would have it looked at by a tech. I think most lower units require special tools to pull gears and such.
before you claim it dead, get someone to look at it
how big were the chunks?
if the pinion gear were actually broken, it would lock into gear without the motor runninng
