Random transmission/engine problem SN200 2016

[Guest]

Hello, new here and hoping for some help.

We have problem at the Ski Club. Sometimes (about 1 of 30 starts) the transmission during start of a skier just goes into neutral for about a second. Most of the times we manage to throttle down, if we don't it goes into gear again quite abruptly. When throttled down, the engine still runs and a new start will go just fine.

This can happen once every other week or sometimes several times on one day, completely random.

 

• Last season the neutral switch on the throttle control failed, we then exchanged the throttle control box for a new one, the problem above then disappeared as well as the faulty neutral switch. The above problem just reappeared after more than half a year , neutral switch still works OK.

 

• Boat SN200 2016, PCM 5.3

 

• Runs at Water Ski club in Sweden, we will still run until the water temp is about 10–15°C (59-59°F)

 

• Oil levels ok (engine 5W30, Transmission Dexron III)

 

• Runs at ski club, so about 10 different drivers.

 

• Seems to be somewhat related to heavier skiers/harder starts but the problem have appeared even with light skier/starts but more unusual.

 

Any ideas would be greatly appreciated!

 

/Kristofer

[BraceMaker]

The thing to realize is that the transmission is always in gear, it is a hydraulic valve that puts pressure into either a forwards or reverse clutch pack.

 

So what it is doing is not holding pressure on the clutch pack.

 

I suspect you are just slipping, I would try a trans fluid change first with possibly a flush - in the US we have a product called seafoam trans tune - but you could also just try new fluid a few times in a row - not sure the recommendation for the PCM transmissions possibly you could flush with kerosene? @Jody_Seal ?

 

I know for a number of older transmissions Kerosene or Diesel were OK to flush the transmissions with, I just suck everything out and run a bottle of seafoam transtune topped up with ATF to the mark and then run it hard for about an hour and replace usually stops slipping.

[Tosse]

thanks for the input!

We have changed the oil, but only once.

Will do a couple of changes and/or look for something to flush with.

 

The thing is that it does not “feel” like slipping, it is so instant and our thoughts are more towards some electronic, even a low voltage have struck our minds although the battery never failed to start i think it is from 2016 (yellow optima).

 

More thougts? Anything appreciated!

 

 

[paul]

Sounds like it could be your electronic shifter malfunctioning at the tranny. With it being fairly infrequent it might be had to test that

[Jody_Seal]

yes check you deutsch connectors at the transmission.

 

[jpwhit]

It can also be the Throttle Base Assembly failing again. How many hours on the boat?

[Tosse]

A bit past 1180 h on the boat now, throttle control replaced at around 1000 h, and everything worked fine for about 100 h after that. Neutral switch still works fine which was another reason for the replacement.

 

Connectors att the tranny have been checked, maybe not so thoroughly, will have another look, any idea on how to measure this intermittent problem at the connectors?

 

Once again, really appreciate all ideas, great forum!

[eyepeeler]

Low tranny fluid? Low tranny fluid is not rare...many people think they are checking it correctly but they aren't.

[Tosse]

Nope, level ok.

[skiinxs]

I would change the throttle box again, they have a high failure rate. (undersized diode burns out) Send the old ones back to Livorsi to have them repaired and keep them for spares.