Yamaha stern drive problems

dave h · 24 July 2001, 19:30

We have a 240 yamaha stern drive with 250 hrs use.The first sign of problems was gear selection becoming difficult,on investigation the selector cylinder was found to be badly scored and there is evidence of swarf on both magnets and the gause filter.The unit is just over a year old.Anyone else got similar problems.

Alan Priddy · 25 July 2001, 07:03

Dave
I would suspect that the lower gears have a problem and need a good look at. It is interesting that you have have this problem at low hours. What type of rib is the unit fitted to? and it will be interesting to know the boats top speed and max revs. I have run this unit for 6 years with no problems and have just finished a very long hour test. What oil do you use? My experiance of failures in this unit are either it has been run for long periods at full revs, the engine is mounted too high or the lower unit spends too much time in the air. Your responce and information would be appriciated
Alan

dave h · 25 July 2001, 18:23

Alan
Thanks for your reply.The boat is a Delta 8.5m,it is running a 23 prop,revs to 3500rpm flat out at which we get 38-39 knots.We would only run flat out for 10mins at a time and usually we cruise at 3000-3200rpm giving 30-32knots.We do not run a commercial operation and the boat is only used for cruising.Oil used is sae90 gear oil as recomended by Yamaha.

Alan Priddy · 06 August 2001, 16:54

Hi Dave

Sorry in the delay in getting back to you.
You have mentioned SAE 90 oil, is it GL4/5 and what make is it? All oils are not the same. We run Spirit on Mobile 1 fully synthetic GL4/5 and although I am touching wood! after 1000 hours I have had no problems. What damage has been done to the lower gears? It would be helpful to know what hight the engine is fitted at. Cheers Alan

a.t.park · 07 August 2001, 17:55

Dave,

Firstly sorry to hear your unit is just over a year old, bad news on the warranty front, good luck with Yamaha!!!!.Just a quick note I have heard rumours that yours may not be the only one, infact I have heard of no less than 4 other similar cases, email me direct and we shall discuss in detail.

dave h · 08 August 2001, 12:14

Alan
The oil used was Texaco GL4 SAE90 semi synthetic gear oil.You were correct the lower gears have a problem,but we are still awaiting a engineers report from yamaha as to the extent of the damage.Once this is recieved i will let you know the outcome.
Do you think fully synthetic oil is the answer? Yamaha tell us only to use semi synthetic! Also do you think running a 23 prop is putting to much stress on the leg?
We have tryed a 21 which gave 3800 rpm and 35 knots.Is it the distance from the bottom of the skeg to the base of the vee you would like to know?
Thanks Dave.

Alan Priddy · 08 August 2001, 15:58

Hi Dave
Who at Yamaha is telling you to use semi synthetic oil? Is it Weybridge or a dealer?
A 23 " prop is fine and not your problem and yes the measurement from the skeg to the V willbe a good indication. When the boat is running hav eyou looked over the stern to see how far th ecavitation plate is out of the water? this would be usefull as well. It was interesting to hear from a.t.park and to hav eonly 4 failures from the numbers of units sold is not a very big problem. Yanmar have had to keep their figures of failures secret until they introduced the new leg at great expence. I need to run our Hydradrive for 1000/1200 hours continuasly next year and I have every confidence that it will do the job.
Cheers

Alan

a.t.park · 20 August 2001, 16:25

Hi Dave,

Well how did you get on with Yamaha and what about the debate on which oil to use.

dave h · 20 August 2001, 18:24

Hi Alan/a.t.
On the oil front Yamaha UK told us that only Yamaha specified ie semi synthetic oil can be used or you have no warranty.The collar for the leg could not physicaly be mounted any lower and the captivation plate is a couple of inches out of the water when running. A new leg has just been purchased and guess what? after 3 hours running and not hard I hasten to add it is showing extreme reluctance to engage gear!
Alan I know you have had no problems,and I hope for your future ventures it remains that way,but if you dont mind me asking is your leg completly standard? or do you have a cooling spray /system? Maybe I am being naive but I would have thought that this sort of product should have had a lifespan of much more than a year at best!

Cheers Dave.

Alan Priddy · 20 August 2001, 19:07

Hi Dave

The legs we have always used on all of our expedition boats are straight out of teh box the same as every ones. We do not belive in teh water spray system as the internal temp of the oil never goes above 75 I know this because we tested a leg for over 500 hours with no problems.I know that soem people are running the plastic cover removed but even then not much water comes up that far. All the heat build up is in the lower leg and then travels up to the top part of the unit.
It would be wrong for me to say who is having problems but it might be worth giving Tom at RedBay boats a call, he sells and fit more units without problems than anyone else ( Except the Marines, who never have problems.)
Keep in touch.

Alan P