89 70 horse Mercury issue (serious? Or minor?)

[Trophyhill]

Hello all, I don't know where else to turn. Since I am not a mechanic, I'm trying to do my homework before going to a boat mechanic.

So I was at lake Powell a couple weekends ago and boat ran great. Caught lots of fish. Hadn't experienced any issues until I throttled up and headed for the boat ramp to go home. I was scooting across the water at a good clip when I heard it felt a pop. Suddenly the rpm's shot up, the boat slowed down, and the motor was putting out a weird looking wake as the front of the boat lifted up more than what I call normal. I limped back to the ramp and trailered the boat. I killed the motor and started it a few times with no trouble and it sounds normal but didn't throttle it up at this point but instead disconnected the fuel line and let it run out of gas as I normally do before heading out.

A friend of a friend said one of his many boats did the same thing and that a rod and piston went out.

Another friend of a friend who knows that guy said he's full of it and that what I described sounds like a rubber boot? Behind the prop may be shot.

Any ideas before I go see a mechanic that I probably can't afford to go see right now?

Thanks in advance,

Dave

 

[Faztbullet]

Spun the hub or hit a large limb that hung up on lower unit.(long story )

 

[roscoe]

I would definitely try a different prop, or test to see if current prop hub has spun, before taking boat to a shop.

 

[DavidMoore]

Your friend of a freind that that knows your friends friend, is right on the button; your friends friend is full of it.


Try a different prop, or
remove the prop and examine the rear, has someone previously made a center dots, one on the hub and one on the prop? If yes and they are not in line then the hubs spun. If not make the center dots go out and give the engine a good run to re-create the condition. Examine the back of the prop and a bob to the pound the dots wont be in line = hubs spun..

Here's a photo plucked from the net to show the dots. Put them on the new prop before you spin it for a quicker diagnosis next time .

 

[Trophyhill]

Thanks guys. I found some YouTube videos on the subject. Sounds like a hub issue. I'm quite a ways from the lake so I'm gonna spend the money and purchase the Flo Torque hub kit. Looks simple to install and doesn't cost very much. The prop doesn't have any visible damage. Can there be damage to the prop that may not be visible that I should be aware of?

 

[Trophyhill]

OK so i took the prop off easy enough. There was a wad of fishing line behind the washer that slides over the shaft. I took it off and put everything back together. Now the prop is nice and tight with no in and out "play" where there was a small amount of play on the prop beforehand. Could this fishing line have been the culprit? Should I wait for the new hub kit to come in before I make the 4 hour drive to Powell? Or do you think I'm good to go? Doesn't appear to be damage to the shaft or bushing to the naked eye. Thanks in advance

Dave

 

[Trophyhill]

Quick update in the chance it helps someone else. I took the boat out on the 4th of July and it looks like my issue was all that fishing line wrapped around the shaft and the shaft nut may have backed off ever so slightly. The boat is back in action and ready to catch fish