Yanmar SD50 Saildrive Problems

[Bryan Leopard44]

I have a 5 year old Leopard 44. The port engine only goes into reverse regardless of shift lever being in forward or reverse. Any idea what problem could be?

It is also leaking oil but it is not in the bilge so it must be leaking outside the boat. Any input here? Can these issues be fixed without hauling the boat?

Thanks,
Bryan

[skipperpete]

If the loss of drive is caused by the infamous SD 50 cone clutch slipping then it can be done in the water provided that the gears themselves are undamaged , however, there is also a chance that the propeller is slipping due to the rubber bush in the prop hub if you have a fixed 2 blade propeller. The oil loss is puzzling, if it was leaking out of the input shaft seal and into the flywheel housing there should be oil in the engine bilge and if it's leaking out the propeller shaft seal the oil in the leg should be milky. It is theoretically possible for the oil to leak past the inner propshaft seal and out via the outer propshaft seal but not get water back in.......unlikely.. but possible.

[Captain Bill]

This actually does not sound like the old cone clutch issue if I am understanding the OP's description correctly. As one who has suffered the cone clutch issue several times in the past this sounds totally different. If I understand it correctly it sounds more like a problem with the shift/throttle system. If you disconnect the shift cable and shift it by hand using the lever on the side of the transmission does it still go into reverse in both the forward and reverse positions?

[Bryan Leopard44]

Captain Bill,

Here is the chain of events. The throttle felt like it was jamming but when it freed up it would stay in the proper gear. Later the sail drive would only go into forward when the lever was in the fwd or rev position. It later would only go into reverse regardless of lever position. At one point it would not go into fwd or reverse. We nursed her back to my dock on one engine and then the next day we disconnected the cable and used the lever directly on the sail drive. Again it would only go into reverse and neutral even when selecting forward.

I am goin to dive now and see if there is anything fouling the prop and then I will run the engine for an hour and see if the sail drive oil is milky.

Thanks,
Bryan

[Bryan Leopard44]

Dove on bottom. Found port prop fouled with fairly heavy fishing line. I removed what I could but it is still fouled. I will need to pull prop. I could not turn the prop by hand while in neutral.

I ran engine for an hour. Saildrive oil did not appear "milky". There were some very tiny bubbles on the top but I would not call it milky.

[GordMay]

Greetings and belated welcome aboard the CF, Bryan.

[Captain Bill]

Good luck and keep an eye on the oil for a while. Fishing line is notoriously bad news on shaft seals. You should consider yourself quite lucky if it does not leak. Running it in neutral won't tell you much and it may take several hours of run time before it becomes evident. If it does show up avoid running the engine at high loads and speeds unless you want to buy a new saildrive. I was trying to make a bridge opening one time and ran the engine at Max continuous RPM for about 20 minutes. The drive got so hot that the water in the oil flashed to steam and blew out every oil seal in the drive and of course all the oil. With no seals intact the drive filled with saltwater and before I could get it hauled every bearing in the drive was ruined. A rebuild was only $800 less than a new drive.

[peterp]

Originally Posted by skipperpete

If the loss of drive is caused by the infamous SD 50 cone clutch slipping then it can be done in the water provided that the gears themselves are undamaged , however, there is also a chance that the propeller is slipping due to the rubber bush in the prop hub if you have a fixed 2 blade propeller. The oil loss is puzzling, if it was leaking out of the input shaft seal and into the flywheel housing there should be oil in the engine bilge and if it's leaking out the propeller shaft seal the oil in the leg should be milky. It is theoretically possible for the oil to leak past the inner propshaft seal and out via the outer propshaft seal but not get water back in.......unlikely.. but possible.

Is the SD 60 (fitted to the Yanmar 45) had any design changes or improvements to avoid premature slipping? any one care to comment, thanks in advance.

[Captain Bill]

Originally Posted by peterp

Is the SD 60 (fitted to the Yanmar 45) had any design changes or improvements to avoid premature slipping? any one care to comment, thanks in advance.

The SD60 is made by a different company and uses disc clutches instead of cone clutches. I had a disc clutch failure at 2 years which was attributed to a manufacturing defect in the early SD60s. Current units do not have this problem which had to do with the ramp angle on the clutch being ground wrong. I've got almost 1.5 years on the replacement units and have not had any more trouble. Of course now that I've said that they'll probably break today.

[SV Bacchus]

Originally Posted by Captain Bill

Of course now that I've said that they'll probably break today.

Ahhh, I see you have my luck. Every time I brag on something, and I have made myself quit, it would invariably take a flaming nose dive!

[peterp]

Originally Posted by Captain Bill

The SD60 is made by a different company and uses disc clutches instead of cone clutches. I had a disc clutch failure at 2 years which was attributed to a manufacturing defect in the early SD60s. Current units do not have this problem which had to do with the ramp angle on the clutch being ground wrong. I've got almost 1.5 years on the replacement units and have not had any more trouble. Of course now that I've said that they'll probably break today.

Captain Bill, how many hours in the 1.5 years? If you don't mind me asking. My SD 50's were 8 years old with 330 hours prior to having any issues apart from normal maintenance including a set of seals.

[Captain Bill]

Originally Posted by peterp

Captain Bill, how many hours in the 1.5 years? If you don't mind me asking. My SD 50's were 8 years old with 330 hours prior to having any issues apart from normal maintenance including a set of seals.

About 750 hours.