Yanmar SD20 no revs in reverse

[doublebubble]

Hi, just wondering if anyone else has experienced this problem with the SD20, just recently our port sail drive (catamaran) has been playing up, on selecting reverse in a normal matter it tends to lock up the engine inturn getting no rpm, if it's slammed into reverse it tends to be ok, not my favourite practice, does anyone else have an idea? all cables, linkages, handset setup have been double checked for correct operation and seem to be fine.

Regards Rod.

[DougR]

Recent thread here which sounded similar......shift into reverse and couldn't throttle up very far.
It was found that the feathering prop, I think it was a Kiwi Prop, was totally dry of lubricant and wouldn't move all the way to the reverse blade position, but would instead hang up half way, acting like a paddle wheel. This caused heavy load on the engine and was enough to hold down RPMs. Subsequent lubrication of the prop resolved the problem.

If you have a similar prop, perhaps when you make an easy shift the force isn't enough to get full blade position change, resulting in no RPM increase. Hard shifting has enough force to drive the blades all the way to the full reverse position, allowing RPM increase. ????

DougR

[doublebubble]

Thanks DougR,
Think you hit the nail on the head, for one, we do have Kiwi props, both props were serviced in March 2019 prior to our departure from Adelaide Sth Australia for the permanent cruising life, props have been great, during our passage around the South East we managed to pick up a couple of cray pot ropes always at 03.00am, managed to remove both of them and everything seemed to be normal, this issue rose it's head about two months later, I've had a good look at the props which seem to be all ok, reverse rollers are free, blades free they seem ok, starting to be a little concerned that it could a selector issue, not engaging fully, cables and hand set have been inspected, shifts fine even with cables disconnected, shifting it manually, but I'm still leaning to the prop.
We're hoping it could just be an intermittent prop problem, hopefully it will be ok until we haul out in a few months and get the prop off for a more detailed inspection

Thanks for the reply, Rod.

[doublebubble]

I'd like to revisit this thread and as of now the port engine Saildrive morsw cable has snapped due to it being jammed in reverse, the cable has now been replaced and are wondering whether anybody has any experience in the correct procedure to set up these cables which have the spring loaded toggle at the gearbox end, this jamming in reverse issue only happens when the kiwiprop is engaged, the shifting is smooth and easy by hand, does anyone have a procedure to set up the SD20 gearbox shift cable.

Rod.

[tkeithlu]

Not that gearbox, per se, but the general statement that no shift cable is intended to take a shock load. Or, for that matter, much of any load. It should just transfer that easy-by-hand movement from the box to the panel. If you want a comparison, put that cable beside the cable that moves an outboard engine - the outboard steering cable is about 1/2" diameter.

Start by making sure that it is well lubricated, because that will be difficult once it is installed. Make sure that the pull and the push at both ends are in line, not off to the side. Remove as much slack as you can in the system, securely mounting both ends. A spring loaded toggle is there to allow the box to take its time about shifting when you push or pull too fast and might damage it.

I hope you build a very happy linkage that will go snik-snik-snik from forward to reverse and back.