IRM 220 sticky selector

[rosssavage]

IRM (zf) 220a, 2009 vintage.

Strange problem - with the engine off, the mechanical gear selection is smooth, free and has positive detent. Once the engine is running (and gearbox oil up to pressure) selecting gear becomes very stiff and slushy. It still goes into and out of gear, but I’m having to use a lot of force on the throttle lever to engage either fwd or astern.

It’s so stiff I’m worried about breaking something in the shift control system!

Throttles regreased, changeover mech regreased...teleflex cables maybe 4 yrs old. I’m convinced the stiffness originates at the gearbox selector- again, with the engine off it feels like it always did, but with the engine running it’s horrendous...

Any previous experience folks, or ideas??

 

[Bandit]

On the quadrant there is a ball bearing on a spring that drops in to a hole for ahead, neutral and astern positions. This stops partly engaged clutches and slipping. If this is not clean and greased it rusts up and will not roll and select.

i suspect this is the problem, if it is, replace with new ball and spring assemblies clean up indents/ holes and grease.

I had this with a 220 a box and EC controls and when I thought the gear box was in astern and acting against other engine manoevering insted of one engine ahead and one astern in manoeuvring I had both ahead, the natural reaction is to give more throttle to kick engine asternharder to turn. Results of manoeuvre were bad. If twin installation. Change both.

 

[rosssavage]

Thanks Bandit - I have considered this as it’s come up during web searches, but the thing that really confuses me is it’s perfect with the engine off (ie no oil px in the box) but gets bad when the engine is running (oil at normal px) suggesting something internal. Parts diagram shows a ridiculously simple valve on the box though - can’t see what would fail so give me the symptoms!

So, change gearbox oil and clean / replace quadrant ball bearing are first actions I guess..

And I’ve had a gear cable fail before, during close quarters manoeuvring - bloody confusing for 30 seconds isn’t it!!

 

[rosssavage]

Solved.

Thanks Bandit (also advised me on parts supplier - thanks!)

The issue was the axial bearing that sits on top of the selector spool valve. Rusty, rusty, rusty. Awaiting spares currently, but I removed the bearing, cleaned it up with solvent and regreased it - selector is now smooth, free and engages with a positive clicky click detent.

Took so long to reply cos wife had a baby last year, so very little boating activity took place.

 

[Bandit]

I had a nasty berthing incident because of these where one engine was stuck in ahead and I did not realise it.A clean up for the moment is one thing but if I were you I would replace both with new spring and ball units and well greased in the very near future.

 

[rosssavage]

Yup, parts on order from Golden Arrow, just thought I’d check that was the issue whilst waiting on delivery - it was

Main problem was the corroded bearing, but the rebuild kits I’ve ordered include bearing, thrust washers, ball and spring (ordered two kits) so it will all be renewed on both sides.

Had a similar issue with a snapped gear cable when manoeuvring in close quarters some years ago. Focussed the mind for a few seconds that one!