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suddenly engine races but wont go 4ward

R

rocket man

New member
Hey Guys, I'm not a novice boater, however I am very, very green around boat motors. The other day I was moving forward slowly through a no wake zone and when it came time to speed up, I pressed forward and the motor raced, but the propeller would not engage. Smoke came from the engine compartment. The boat would go in reverse, however. I was in deep water and did not hit anything. I have a 1999 Mercruiser 205hp I/O. Any suggestions as to what the problem may be? Thanks for your help!
 
Your engine drive coupler failed. You have to pull the engine out to change it unfortunately. This is a common issue. The rear engine mounts get old, or the front engine mounts comes loose, allowing the engine to move- this misaligns the coupler and it fails. A new coupler and alignment bar are needed.

Insect the front engine mount lag screws - make sure the wood isn't rotten where they screw in.
 
Oh no! That sounds like a lot of expensive work!! How does the boat go in reverse if the coupler is broken? I was told it could also be the "saver hub." I've tried to find a diagram of a saver hub and its location but no luck. I really don't know anything about motors. When I was a kid I could fix a cotter pin, but that's about the extent of my skills. I was hoping that this might be something I could fix, but if it requires pulling the engine then I'm way over my head.
 
If you had smoke from the engine compartment, I too suspect the coupler. A spun prop hub will typically still allow you to accelerate either forward or reverse (I spun mine 2 weeks ago but could still get on plane, about $75 to replace). You can try a spare prop to validate, but I suspect the worst. Best of luck....
 
If the boat is on a trailer, put it into reverse, grab the prop and push hard to the right.
If you can get it to spin. see if the drive shaft to the coupler is moving or not.
 
vandyman said:
A spun prop hub will typically still allow you to accelerate either forward or reverse (I spun mine 2 weeks ago but could still get on plane, about $75 to replace). You can try a spare prop to validate, but I suspect the worst. Best of luck....
Click to expand...

Not with a sacrificial hub, when it's spun, it's gone. But the good side is they are only $35 - $40 bucks and your back on the water.
 
I used my spare prop with no problems, and took the "spun" prop (Stiletto model) to my local prop-shop who installed a new hub.... the type I have requires a press to install. I didn't push it past about 15mph, but could get on plane. I think the Merc hubs (Flo-Tork?) may be simple inserts that, when spun, are pretty much 100% gone. Thank goodness I could still putter back to the marina as I did not have the spare with me at the time (do now though).
 
vandyman said:
I used my spare prop with no problems, and took the "spun" prop (Stiletto model) to my local prop-shop who installed a new hub.... the type I have requires a press to install. I didn't push it past about 15mph, but could get on plane. I think the Merc hubs (Flo-Tork?) may be simple inserts that, when spun, are pretty much 100% gone. Thank goodness I could still putter back to the marina as I did not have the spare with me at the time (do now though).
Click to expand...

That's what I thought you meant was a flo-torq type of "saver" hub.
 
Listen i always have a spare prop onboard, maybe no beer, bait or whatever but under the seat is a spare prop.

Saved the day more then once.

Glad it was the prop. The alternatives are not good.
 
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