Shift cable or shift interupt switch?

B

bago

Petty Officer 3rd Class
Joined
Jan 19, 2007
Messages
86
Hello everyone!Yesterday I was cruising at 3200rpm with my 20ftboat Merc 170 Alpha1 when suddenly the engine went out of gear and revved up.I shut it down,restarted again,but I couldn`t into gear any more.No forward or reverse.I couldn`t hear any atempt of the drive to engage.We were six grown -ups on the boat but that`s within the capacity of the boat.Should I immediately take the drive off for shift cable change,or look closely at the interupt switch,because when I put the control in fwd or rev only the engine revs up,but sometimes it dies as well.Thank you in advance!
 
OldDriver

OldDriver

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Joined
Aug 10, 2008
Messages
22
Re: Shift cable or shift interupt switch?

My guess would be a shift cable break not letting you shift, blown coupler or spun prop hub. Shift interupt switch would shut the engine down (if stuck closed) or make it hard to shift.
Just my WAG.
 
W

Wakesilver

Petty Officer 3rd Class
Joined
Jun 21, 2009
Messages
76
Re: Shift cable or shift interupt switch?

Hello Bago-
Did you notice any rise in engine temperature or any smells like buring rubber?
My boat did something similar and it was a bad engine coupler. When the coupler goes bad the motor will rev and the water pump in the outdrive will not supply water to cool the motor.
-WS
 
B

bago

Petty Officer 3rd Class
Joined
Jan 19, 2007
Messages
86
Re: Shift cable or shift interupt switch?

Thank you for the response!Ididn`t smell any burned rubber or notice any temperature rise at all.What I would like to know is if there is a trouble shooting method to diagnose shift cable issue?
 
Bondo

Bondo

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70,524
Re: Shift cable or shift interupt switch?

I was cruising at 3200rpm with my 20ftboat Merc 170 Alpha1 when suddenly the engine went out of gear and revved up.
Click to expand...

Ayuh,... 2 things that did Not cause the Problem are the Shift Cable or the Switch....
If your Lucky,... You need a new Prop,...
Otherwise, you probably need a new Drive....
 
OldDriver

OldDriver

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Aug 10, 2008
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Re: Shift cable or shift interupt switch?

Thanks Bondo, while out on my boat today I was thinking about this and rembered he could have lost the gears in the upper unit. Which would be a bad/expensive thing.:eek:
 
B

bago

Petty Officer 3rd Class
Joined
Jan 19, 2007
Messages
86
Re: Shift cable or shift interupt switch?

Thanks all of you!Will opening the lid of the upper gears confirm or exclude the gear problem?
 
B

bago

Petty Officer 3rd Class
Joined
Jan 19, 2007
Messages
86
Re: Shift cable or shift interupt switch?

It`s all clear- upper gears are toasted.The oil in the drive was about 1\2 liter and contaminated with water.Wonder if the lower unit gears have survived?What will you advise new drive repair set or a new drive?Thanks all of you fellas!
 
jaxnjil

jaxnjil

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Aug 3, 2007
Messages
1,368
Re: Shift cable or shift interupt switch?

if you lost your top gear set then the chance you have contaminated your lower gears with metal is high. the lower ran with the water contaminated oil any way and your lower seals are a good candidate for the water intrusion in the first place. all in all your best bet will be one of the SEI new drives. you can pick one up here at i-boats and you cant beat the 3 year no fault warrenty
 
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