No power in reverse

[dbbd]

New problem on our boat. Engaging reverse works, but applying throttle does not ramp up revs.
The throttle does pull the engine throttle in both forward and reverse. Without engaging gears reverse does increase engine revs, but when gear is engage it does not.

Any advise would’ve appreciated
Dan

[Rumrace]

Which engine transmission drive or shaft
More clues please

[Rumrace]

Sounds like a dog clutch in an outboard and a bent rack or shifter.
Sea Drive Clutch - Bad oil , polished clutch
Not being able to increase rpm sounds like gears binding so not fully engaged.
Do you have a folding prop. Have you increased you prop pitch or 2-3 blade swap

[Rumrace]

First check is shifter cable where it connects to the transmission
With the engine off in neutral can you spin the prop or prop shaft easily.
Could be as simple as a seized cable. Cable. Lube takes a day to work so be patient. A cone or dog clutch is designed to slam into gear a micro switch temporarily stops spark to the plugs during the shift.
The Sea Drive clutches are a collection of mistakes and replacement clutches. They are gentle shifts. They depend on a corse surface pairs. As they get polished smooth you can resurface them and reinstall. Typically this will give you 500 hours instead of the 2000 hours various clutch types survive.

[dbbd]

Originally Posted by Rumrace

Which engine transmission drive or shaft
More clues please

The metal tab say model ZF 30 H.
I have no idea what it is.

[pesarsten]

Does your helm control have separate handles for shift and throttle or one handle?

[dbbd]

Originally Posted by pesarsten

Does your helm control have separate handles for shift and throttle or one handle?

One handle

[pesarsten]

problem could be in mechanism for shift/throttle handle, can you verify movement of arm on injection pump when in gear. Perhaps move throttle while engine off and compare movement both in gear and out of gear?

[donradcliffe]

That's an unusual problem. Look closely at the throttle lever at the engine. If it moves equally both in and out of gear, is there any extra noise or vibration when you are in gear--ie is the engine trying harder? Does it the engine work normally in forward gear? If so, you have big transmission or prop problems.

[Rumrace]

ZF is a wonderful transmission builder for BMW Mercedes Corvette and Sea Drive.
What’s weird is it’s forward which is not suppose to work if it’s your Sea Drive Clutch.
I think it could be a cable issue and easy to resolve. There should be two cables coming into the engine room on a twin clamp. Assure the cables are snug there. Disconnect the shifter cable at the ZF with help from the helm assure the cables run smoothly.
If everything is fine there it could be water in your ZF oil. They swell have no place to displace an Overfill. They get abused used as generators in neutral still spinning with no load.
Lastly it could be the prop or the anode.

[Rumrace]

Darn it can also be the shifter throttle itself. Depending on the brand there are two rotating plates the shifter plate get dropped off after a few degree and your throttle plate goes either way for throttle. It is by design limited in reverse so could be an issue in there.

[skipperpete]

Could this loss of engine power in reverse be somehow related to your earlier engine failure, hopefully you found the cause of the shutdown. I’m curious to know if the engine performs normally in forward.
Pete.

[hzcruiser]

Originally Posted by dbbd

One handle

Take that apart first and you'll see.

[01kiwijohn]

You don't happen to have a feathering prop on that boat, do you? I've encountered situations where the prop is not engaging properly, one blade was still feathered, causing an enormous amount of resistance. The engine would not spool up past about 1500 RPM whereas normally it would go well past 2200.

[Uncle Bob]

Looks remarkably like what used to be a hurth, multi plate clutch arrangement that had a reputation for slipping with a few hours on it. Research suggested that there are better solutions out there, I went with a PRM which was an easy fit and no more problems. The quoted repair price was $200 dollars shy of the PRM so a no brainer for me.