smdude

Hey guys, searched and read all post about BW trans slipping, but have some what different problem! Have 83 Fountain, 10meter, Velvet drive Model 72C trans, have slipping at about 2000-2500 rpm getting on plane. Checked the fluid, seems fine no burnt look or smell, I am using Type F trans fluid (new) this year, checked the dipstick it is the right one for this trans. If you feather the thottle down, is seems to catch up the the other starboard motor-trans fine, at cruise speed it runs OK and the wake looks good, the other trans is fine, no slipping, and the trans in question is the port side reverse rotation prop. This boat is new to me, have no idea how it ran for the other owner! Thanks

Audiofn

You sure it is the tranny slipping and not your prop blowing out?

smdude

Not sure, maybe it is the prop. (I hope so) The props are a 3 blade Mirage. What can I look for, or hear if it is a prop problem? Thanks audiofin

Chris Sunkin

Or the prop spinning on the hub.

When the trans starts to slip, it gets worse and it cooks the fluid. It also will "creep" in neutral from the warped plates. If you put the trans in neutral and the prop continues to turn you have a cooked 72c. (this is something you check tied to a dock.)

smdude

Chris, checked the prop on the drive, everthing is tight and no wear the the thrust washer or anything. When we came into the launch last nite, the boat shifted into forward and reverse just fine, both motors-trans, I'm hoping its a cavition problem, as I don't want to pull the motor again! If its a prop problem, what can I look for next. When we had the boat out on it's trial run the trans worked fine, up on plate in about 4-5 sec. running the throttles easy, and letting the boat run up. I have noticed this problem with the lake at about 2 maybe 3 foot waves, could this be cavition problem, this is my first twin motor boat.

Ratickle

If it only slips coming up on plane, best guess is the prop. Every time I've puked a trans, it has been the most noticeable under hard acceration while already on plane. After a couple of times/gone!! Should be no problem, test by bringing the boat up on plane as slow as possible or once on plane and running barely on plane, hammer it. Others will know better, but if you borrow some four blades and it goes away, or pukes the trans, know for sure.

Chris Sunkin

I'm assuming then you have solid hubs on those props. I was talking about props that have separate hubs.

Raticle is right on all counts there. You may want to call BBBlades or Hydromotive, once you've determined you don't have a smoked trans

smdude

Thanks guys, looks like I have some testing ahead!

spazboz

iTrader: (2)

On a few of the twin engine boats with TRS, I have found that if there is a substantial power difference between the two motors, this can also cause this. I had a 357 this year that was doing the same thing. Turns out he had one of the motors timing at 9 degree's BTDC, and the other set at 2 ATDC. The engine with the timing set correctly would blow out while trying to plane, and at WOT would run 6-700 RPM more. It's easy to check, and costs nothing but a couple of minutes of your time. He assumed the worst and brought it to me for trans rebuild. Turn's out a little simple tuning, and he was on his way. He has put over a 50 hours on the boat since with no issues.
Nick

smdude

Funny you should mention that spazboz, the motor and trans that is blowing out or slipping is more powerful than the other. I bought both motors from the same guy, but he later had problems with the port motor in the repair shop before I picked them up, found out he had to replace one piston and rings, he make everything right, but after turning each motor over with the same starter, the port motor does have more compression. Never thought about that, being a possible problem, but I've never had 2 motors in a boat before!