Drive slips out of gear at 1700 RPM.

Chunks77

Cadet
Joined
Jul 12, 2011
Messages
14
I have a 4.3 liter Mercruiser Alpha One I/O and upon throttle up, at 1700 rpm, i lose "thrust" and the boat slows back down while the RPMs continue to climb. There's no clunk or any other sound that I can hear other than the engine revving up. When I bring the throttle back down, the prop seems to reengage and continue along, just as long as it stays below 1700.

On the advice of a local mechanic, I removed the prop and didn't notice anything out of the ordinary as far as I could tell. Don't see any metal pieces or shavings, and it doesn't look stripped or damaged. I assume any damage in there would be obvious.

This first happened at the end of a day on the lake while I had the throttle wide open for about 5-7 minutes. Engine temp was fine, oil pressure had been running higher than normal as a trend and all fluids are normal.

On a side note, my blower stopped working as well. Most likely unrelated I think but it happened just about the same time.

Thanks in advance for any help!
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,350
Re: Drive slips out of gear at 1700 RPM.

On the advice of a local mechanic, I removed the prop and didn't notice anything out of the ordinary as far as I could tell. Don't see any metal pieces or shavings, and it doesn't look stripped or damaged. I assume any damage in there would be obvious.

Ayuh,... Depending on hub design, ya gotta mark it, run it, 'n see if the marks still line up...

My guess is the Prop Hub,...
Only other thing it could be is the Coupler...
They usually just Quit, 'n leave rubber dust all over the back of the motor...
 

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: Drive slips out of gear at 1700 RPM.

lol........

the blower is your problem......make sure you use rain ex or vasoline in the blades..:eek::eek::D..lol

sorry ....just kidding.

if your prop hub is good.....it has to be the coupler.
your lucky you were able to hold 1700....dont take the boat out again without inspection and replacement or your swimmin back with a tow rope in your teeth.

cheers
oops
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Drive slips out of gear at 1700 RPM.

lol........

the blower is your problem......make sure you use rain ex or vasoline in the blades..:eek::eek::D..lol

sorry ....just kidding.

if your prop hub is good.....it has to be the coupler.
your lucky you were able to hold 1700....dont take the boat out again without inspection and replacement or your swimmin back with a tow rope in your teeth.

cheers
oops
toothlessgiggler.gif
lolhit.gif


Yeah..... my old Marktwain did the same thing when the coupler failed. It got progressively worse very quickly. Luckily, I was still in the ramp area when it did it for the last time.


If it's your coupler, you must remove the drive and engine (in that order) to replace!


Regards,


Rick







Oh.......and Welcome to iboats!!
 
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