89 Supra Mariah Dirty Neutral

Hello everybody I am new to the supra boat forum and I was hoping someone could point me in the right direction with some issue that I am having with my boat. 1st off is the other day when I did a oil change and put new spark plugs in I fired up the boat to check everything and I noticed that the transmission was spinning the prop like it was in gear but the throttle was in the neutral position I have been checking around the net to see what I could learn about the issue so far all I have come across is that clutch plates might be warped I was wondering if there are any other solutions or any thing else that might cause this to happen such as out of adjustment on the cable ect. and what I should try and do 1st to see if I can get this resolved before having to take it in. also what would be the worst to happen if I went ahead and ran it like that for the rest of the summer then get it taken care of in the winter. Any help and advise would be great thank you
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Welcome to Supra Forums!

What transmission does your boat have?

How fast is the prop spinning?

My 92 with a PCM 1.23:1 transmission doesn't do it, but dad had a Mastercraft in the 80's with a Borg-Warner transmission that would slowly spin the prop in neutral when running on the trailer.

Thanks for the welcome umm it has the Borg and Warner 1.23:1 transmission in it and it spins quick enough not to see the blades individual also we bought the boat at the end of last summer and it would barely spin then when we took it out twice last season but when we bought it I don't know when the last owner changed the trans fluid in it so I am kinda stumped with it. a transmission shop said they have dealt with velvet drives before and it would cost me 175 just to look at it so I was hoping I could try something before I had to go and drop that coin on it .

https://youtu.be/Ts-Pf2k7kAU

Definitely not normal. The prop on dad's old MC just barely turned. I would not feel safe trying to maneuver that boat around the dock or skiers. Either get it looked at pronto or order the manual and parts and do it yourself if you're mechanically apt and have a good supply of tools.

Just so you know. If it's a 1.23:1 transmission, I don't think BW made one in that ratio for ski boats, just a 1:1 and a 1.52:1. If it's a 1.23:1, it likely a PCM transmission. A pic of the transmission would tell for sure.

Discount Inboard Marine carries that parts and manuals to fix either brand of transmission if you want to go that route. http://www.skidim.com/Transmissions/departments/1098/

Here's a copy of the manual of the PCM 1.23 transmission.
http://engines1.novosolutions.net/re...6&fstore=&SID=

Here is the manual for Borg Warner Velvet-Drive transmissions.
http://www.mikesell.net/mastercraft/Velvet70C&71C.pdf

It's not an uncommon issue. And, in the water under a ton+ of boat it likely doesn't spin as fast. Does it propel the boat in the water in neutral?

Doubtful it's an adjustment as the boat shouldn't start unless the transmission is in neutral but you can try anyway. Disconnect the transmission cable at the transmission. The lever on the transmission should have a noticeable indent when you reach neutral from forward or reverse.