Damper / Flex Plate? 05 Indmar 5.7L - Stuck in neutral? Will not spin prop shaft

EdgarAllanBRO

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Joined
Jul 19, 2015
Messages
2
05 Mobius XLV, (V Drive)
Indmar Assault 5.7L,
Hurth ZF 45 CW Transmission


It has not been ran too much in the past couple of years. Starts up fine every time. When barely put into gear it runs rough, like the idle is too low and you can hear a clicking noise even with the hatch down. The noise disappears and the engine runs much smoother when you get it up to about 800 rpm. So I increased the idle with the idle adjustment screw next to the carburetor so that it idles at the higher 800 rpm.


Since then the boat has run great, with no clicking or noise in the higher idle for the past couple of trips (15 hours). Yesterday evening on the way back to the boat ramp (2500 rpm) it somehow slipped into neutral and was no longer spinning the prop shaft. There was NO loud or unusual noises when this happened... Boat still running great, but could not get it into gear, forward or reverse. It simply acted as if it was STUCK IN NEUTRAL. The neutral button on the throttle was working properly. Jumped in, prop is there, and can spin as normal with my hand. Decided to check my throttle cables, both to carb, and to transmission, and both functioning properly. Checked prop shaft coupling bolts, and everything seemed fine. Fluids were all full. Transmission fluid is slightly brown compared to its normal pink. It was getting dark, and someone else heading to the boat ramp was nice enough to tow us back. While being towed the prop and shaft spun smoothly, so no issues there.


If the damper plate is the issue could I completely lose the ability to put the boat in gear and turn the shaft?
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Is there anything else I should check before pulling transmission and motor and checking the damper plate?


Thank you for any input!!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,499
I would suspect the trans prior to your flywheel or coupler
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,513
Ayuh,..... Welcome Aboard,..... I really don't know alot 'bout yer transmission, but I too, suspect it over the flex-plate,.....
Or yes, the flex-plate could also be the problem,....

With either one, pullin' the tranny is step #1,...
 

EdgarAllanBRO

Recruit
Joined
Jul 19, 2015
Messages
2
Pulled the starter and there were springs and other metal pieces from the damper late laying in the bellhousing. Bought a new damper plate from skidim and will hopefully get the chance to replace it in 2 weeks. Thanks for the input
 

Durango318

Seaman
Joined
Jun 12, 2010
Messages
68
When a damper is on the way out, it can be detrimental to everything associated to the trany's input shaft. Considering it ran 15 hrs after it was first noted and the oil is discolored. If it were me, I'd be pulling it out and inspecting it, with special attention to bearings/bushings.
 
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